Package org.apache.commons.io

Class IOUtils

java.lang.Object

org.apache.commons.io.IOUtils

public class IOUtils
extends Object

General IO stream manipulation utilities.

This class provides static utility methods for input/output operations.

• closeQuietly - these methods close a stream ignoring nulls and exceptions
• toXxx/read - these methods read data from a stream
• write - these methods write data to a stream
• copy - these methods copy all the data from one stream to another
• contentEquals - these methods compare the content of two streams

The byte-to-char methods and char-to-byte methods involve a conversion step. Two methods are provided in each case, one that uses the platform default encoding and the other which allows you to specify an encoding. You are encouraged to always specify an encoding because relying on the platform default can lead to unexpected results, for example when moving from development to production.

All the methods in this class that read a stream are buffered internally. This means that there is no cause to use a BufferedInputStream or BufferedReader. The default buffer size of 4K has been shown to be efficient in tests.

The various copy methods all delegate the actual copying to one of the following methods:

• copyLarge(InputStream, OutputStream, byte[])
• copyLarge(InputStream, OutputStream, long, long, byte[])
• copyLarge(Reader, Writer, char[])
• copyLarge(Reader, Writer, long, long, char[])

For example, copy(InputStream, OutputStream) calls copyLarge(InputStream, OutputStream) which calls copy(InputStream, OutputStream, int) which creates the buffer and calls copyLarge(InputStream, OutputStream, byte[]).

Applications can re-use buffers by using the underlying methods directly. This may improve performance for applications that need to do a lot of copying.

Wherever possible, the methods in this class do not flush or close the stream. This is to avoid making non-portable assumptions about the streams' origin and further use. Thus the caller is still responsible for closing streams after use.

Provenance: Excalibur.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	CR	CR char '13'.
static final int	DEFAULT_BUFFER_SIZE	The default buffer size (8192) to use in copy methods.
static final char	DIR_SEPARATOR	The system directory separator character.
static final char	DIR_SEPARATOR_UNIX	The Unix directory separator character ''/''.
static final char	DIR_SEPARATOR_WINDOWS	The Windows directory separator character ''\\''.
static final byte[]	EMPTY_BYTE_ARRAY	A singleton empty byte array.
static final int	EOF	Represents the end-of-file (or stream) value -1.
static final int	LF	LF char '10'.
static final String	LINE_SEPARATOR	Deprecated. Use System.lineSeparator().
static final String	LINE_SEPARATOR_UNIX	The Unix line separator string.
static final String	LINE_SEPARATOR_WINDOWS	The Windows line separator string.

Constructor Summary

Constructors

Constructor	Description
IOUtils()	Deprecated. TODO Make private in 3.0.

Method Summary

Modifier and Type	Method	Description
static BufferedInputStream	buffer(InputStream inputStream)	Returns the given InputStream if it is already a BufferedInputStream, otherwise creates a BufferedInputStream from the given InputStream.
static BufferedInputStream	buffer(InputStream inputStream, int size)	Returns the given InputStream if it is already a BufferedInputStream, otherwise creates a BufferedInputStream from the given InputStream.
static BufferedOutputStream	buffer(OutputStream outputStream)	Returns the given OutputStream if it is already a BufferedOutputStream, otherwise creates a BufferedOutputStream from the given OutputStream.
static BufferedOutputStream	buffer(OutputStream outputStream, int size)	Returns the given OutputStream if it is already a BufferedOutputStream, otherwise creates a BufferedOutputStream from the given OutputStream.
static BufferedReader	buffer(Reader reader)	Returns the given reader if it is already a BufferedReader, otherwise creates a BufferedReader from the given reader.
static BufferedReader	buffer(Reader reader, int size)	Returns the given reader if it is already a BufferedReader, otherwise creates a BufferedReader from the given reader.
static BufferedWriter	buffer(Writer writer)	Returns the given Writer if it is already a BufferedWriter, otherwise creates a BufferedWriter from the given Writer.
static BufferedWriter	buffer(Writer writer, int size)	Returns the given Writer if it is already a BufferedWriter, otherwise creates a BufferedWriter from the given Writer.
static byte[]	byteArray()	Returns a new byte array of size DEFAULT_BUFFER_SIZE.
static byte[]	byteArray(int size)	Returns a new byte array of the given size.
static void	close(Closeable closeable)	Closes the given Closeable as a null-safe operation.
static void	close(Closeable... closeables)	Closes the given Closeables as null-safe operations.
static void	close(Closeable closeable, IOConsumer<IOException> consumer)	Closes the given Closeable as a null-safe operation.
static void	close(URLConnection conn)	Closes a URLConnection.
static void	closeQuietly(Closeable closeable)	Closes a Closeable unconditionally.
static void	closeQuietly(Closeable... closeables)	Closes a Closeable unconditionally.
static void	closeQuietly(Closeable closeable, Consumer<Exception> consumer)	Closes the given Closeable as a null-safe operation while consuming IOException by the given consumer.
static void	closeQuietly(InputStream input)	Closes an InputStream unconditionally.
static void	closeQuietly(OutputStream output)	Closes an OutputStream unconditionally.
static void	closeQuietly(Reader reader)	Closes an Reader unconditionally.
static void	closeQuietly(Writer writer)	Closes an Writer unconditionally.
static void	closeQuietly(Iterable<Closeable> closeables)	Closes an iterable of Closeable unconditionally.
static void	closeQuietly(ServerSocket serverSocket)	Closes a ServerSocket unconditionally.
static void	closeQuietly(Socket socket)	Closes a Socket unconditionally.
static void	closeQuietly(Selector selector)	Closes a Selector unconditionally.
static void	closeQuietly(Stream<Closeable> closeables)	Closes a stream of Closeable unconditionally.
static long	consume(InputStream input)	Consumes bytes from a InputStream and ignores them.
static long	consume(Reader input)	Consumes characters from a Reader and ignores them.
static boolean	contentEquals(InputStream input1, InputStream input2)	Compares the contents of two Streams to determine if they are equal or not.
static boolean	contentEquals(Reader input1, Reader input2)	Compares the contents of two Readers to determine if they are equal or not.
static boolean	contentEqualsIgnoreEOL(Reader reader1, Reader reader2)	Compares the contents of two Readers to determine if they are equal or not, ignoring EOL characters.
static QueueInputStream	copy(ByteArrayOutputStream outputStream)	Copies bytes from a ByteArrayOutputStream to a QueueInputStream.
static int	copy(InputStream inputStream, OutputStream outputStream)	Copies bytes from an InputStream to an OutputStream.
static long	copy(InputStream inputStream, OutputStream outputStream, int bufferSize)	Copies bytes from an InputStream to an OutputStream using an internal buffer of the given size.
static void	copy(InputStream input, Writer writer)	Deprecated. Use copy(InputStream, Writer, Charset) instead
static void	copy(InputStream input, Writer writer, String inputCharsetName)	Copies bytes from an InputStream to chars on a Writer using the specified character encoding.
static void	copy(InputStream input, Writer writer, Charset inputCharset)	Copies bytes from an InputStream to chars on a Writer using the specified character encoding.
static void	copy(Reader reader, OutputStream output)	Deprecated. Use copy(Reader, OutputStream, Charset) instead
static void	copy(Reader reader, OutputStream output, String outputCharsetName)	Copies chars from a Reader to bytes on an OutputStream using the specified character encoding, and calling flush.
static void	copy(Reader reader, OutputStream output, Charset outputCharset)	Copies chars from a Reader to bytes on an OutputStream using the specified character encoding, and calling flush.
static int	copy(Reader reader, Writer writer)	Copies chars from a Reader to a Writer.
static long	copy(Reader reader, Appendable output)	Copies chars from a Reader to a Appendable.
static long	copy(Reader reader, Appendable output, CharBuffer buffer)	Copies chars from a Reader to an Appendable.
static long	copy(URL url, File file)	Copies bytes from a URL to an OutputStream.
static long	copy(URL url, OutputStream outputStream)	Copies bytes from a URL to an OutputStream.
static long	copyLarge(InputStream inputStream, OutputStream outputStream)	Copies bytes from a large (over 2GB) InputStream to an OutputStream.
static long	copyLarge(InputStream inputStream, OutputStream outputStream, byte[] buffer)	Copies bytes from a large (over 2GB) InputStream to an OutputStream.
static long	copyLarge(InputStream input, OutputStream output, long inputOffset, long length)	Copies some or all bytes from a large (over 2GB) InputStream to an OutputStream, optionally skipping input bytes.
static long	copyLarge(InputStream input, OutputStream output, long inputOffset, long length, byte[] buffer)	Copies some or all bytes from a large (over 2GB) InputStream to an OutputStream, optionally skipping input bytes.
static long	copyLarge(Reader reader, Writer writer)	Copies chars from a large (over 2GB) Reader to a Writer.
static long	copyLarge(Reader reader, Writer writer, char[] buffer)	Copies chars from a large (over 2GB) Reader to a Writer.
static long	copyLarge(Reader reader, Writer writer, long inputOffset, long length)	Copies some or all chars from a large (over 2GB) InputStream to an OutputStream, optionally skipping input chars.
static long	copyLarge(Reader reader, Writer writer, long inputOffset, long length, char[] buffer)	Copies some or all chars from a large (over 2GB) InputStream to an OutputStream, optionally skipping input chars.
static int	length(byte[] array)	Returns the length of the given array in a null-safe manner.
static int	length(char[] array)	Returns the length of the given array in a null-safe manner.
static int	length(CharSequence csq)	Returns the length of the given CharSequence in a null-safe manner.
static int	length(Object[] array)	Returns the length of the given array in a null-safe manner.
static LineIterator	lineIterator(InputStream input, String charsetName)	Returns an Iterator for the lines in an InputStream, using the character encoding specified (or default encoding if null).
static LineIterator	lineIterator(InputStream input, Charset charset)	Returns an Iterator for the lines in an InputStream, using the character encoding specified (or default encoding if null).
static LineIterator	lineIterator(Reader reader)	Returns an Iterator for the lines in a Reader.
static int	read(InputStream input, byte[] buffer)	Reads bytes from an input stream.
static int	read(InputStream input, byte[] buffer, int offset, int length)	Reads bytes from an input stream.
static int	read(Reader reader, char[] buffer)	Reads characters from an input character stream.
static int	read(Reader reader, char[] buffer, int offset, int length)	Reads characters from an input character stream.
static int	read(ReadableByteChannel input, ByteBuffer buffer)	Reads bytes from a ReadableByteChannel.
static void	readFully(InputStream input, byte[] buffer)	Reads the requested number of bytes or fail if there are not enough left.
static void	readFully(InputStream input, byte[] buffer, int offset, int length)	Reads the requested number of bytes or fail if there are not enough left.
static byte[]	readFully(InputStream input, int length)	Reads the requested number of bytes or fail if there are not enough left.
static void	readFully(Reader reader, char[] buffer)	Reads the requested number of characters or fail if there are not enough left.
static void	readFully(Reader reader, char[] buffer, int offset, int length)	Reads the requested number of characters or fail if there are not enough left.
static void	readFully(ReadableByteChannel input, ByteBuffer buffer)	Reads the requested number of bytes or fail if there are not enough left.
static List<String>	readLines(InputStream input)	Deprecated. Use readLines(InputStream, Charset) instead
static List<String>	readLines(InputStream input, String charsetName)	Gets the contents of an InputStream as a list of Strings, one entry per line, using the specified character encoding.
static List<String>	readLines(InputStream input, Charset charset)	Gets the contents of an InputStream as a list of Strings, one entry per line, using the specified character encoding.
static List<String>	readLines(Reader reader)	Gets the contents of a Reader as a list of Strings, one entry per line.
static List<String>	readLines(CharSequence csq)	Gets the contents of a CharSequence as a list of Strings, one entry per line.
static byte[]	resourceToByteArray(String name)	Gets the contents of a resource as a byte array.
static byte[]	resourceToByteArray(String name, ClassLoader classLoader)	Gets the contents of a resource as a byte array.
static String	resourceToString(String name, Charset charset)	Gets the contents of a resource as a String using the specified character encoding.
static String	resourceToString(String name, Charset charset, ClassLoader classLoader)	Gets the contents of a resource as a String using the specified character encoding.
static URL	resourceToURL(String name)	Gets a URL pointing to the given resource.
static URL	resourceToURL(String name, ClassLoader classLoader)	Gets a URL pointing to the given resource.
static long	skip(InputStream input, long skip)	Skips bytes from an input byte stream.
static long	skip(InputStream input, long skip, Supplier<byte[]> skipBufferSupplier)	Skips bytes from an input byte stream.
static long	skip(Reader reader, long toSkip)	Skips characters from an input character stream.
static long	skip(ReadableByteChannel input, long toSkip)	Skips bytes from a ReadableByteChannel.
static void	skipFully(InputStream input, long toSkip)	Skips the requested number of bytes or fail if there are not enough left.
static void	skipFully(InputStream input, long toSkip, Supplier<byte[]> skipBufferSupplier)	Skips the requested number of bytes or fail if there are not enough left.
static void	skipFully(Reader reader, long toSkip)	Skips the requested number of characters or fail if there are not enough left.
static void	skipFully(ReadableByteChannel input, long toSkip)	Skips the requested number of bytes or fail if there are not enough left.
static InputStream	toBufferedInputStream(InputStream input)	Fetches entire contents of an InputStream and represent same data as result InputStream.
static InputStream	toBufferedInputStream(InputStream input, int size)	Fetches entire contents of an InputStream and represent same data as result InputStream.
static BufferedReader	toBufferedReader(Reader reader)	Returns the given reader if it is a BufferedReader, otherwise creates a BufferedReader from the given reader.
static BufferedReader	toBufferedReader(Reader reader, int size)	Returns the given reader if it is a BufferedReader, otherwise creates a BufferedReader from the given reader.
static byte[]	toByteArray(InputStream inputStream)	Gets the contents of an InputStream as a byte[].
static byte[]	toByteArray(InputStream input, int size)	Gets the contents of an InputStream as a byte[].
static byte[]	toByteArray(InputStream input, long size)	Gets contents of an InputStream as a byte[].
static byte[]	toByteArray(Reader reader)	Deprecated. Use toByteArray(Reader, Charset) instead
static byte[]	toByteArray(Reader reader, String charsetName)	Gets the contents of a Reader as a byte[] using the specified character encoding.
static byte[]	toByteArray(Reader reader, Charset charset)	Gets the contents of a Reader as a byte[] using the specified character encoding.
static byte[]	toByteArray(String input)	Deprecated. Use String.getBytes() instead
static byte[]	toByteArray(URI uri)	Gets the contents of a URI as a byte[].
static byte[]	toByteArray(URL url)	Gets the contents of a URL as a byte[].
static byte[]	toByteArray(URLConnection urlConnection)	Gets the contents of a URLConnection as a byte[].
static char[]	toCharArray(InputStream inputStream)	Deprecated. Use toCharArray(InputStream, Charset) instead
static char[]	toCharArray(InputStream inputStream, String charsetName)	Gets the contents of an InputStream as a character array using the specified character encoding.
static char[]	toCharArray(InputStream inputStream, Charset charset)	Gets the contents of an InputStream as a character array using the specified character encoding.
static char[]	toCharArray(Reader reader)	Gets the contents of a Reader as a character array.
static InputStream	toInputStream(CharSequence input)	Deprecated. Use toInputStream(CharSequence, Charset) instead
static InputStream	toInputStream(CharSequence input, String charsetName)	Converts the specified CharSequence to an input stream, encoded as bytes using the specified character encoding.
static InputStream	toInputStream(CharSequence input, Charset charset)	Converts the specified CharSequence to an input stream, encoded as bytes using the specified character encoding.
static InputStream	toInputStream(String input)	Deprecated. Use toInputStream(String, Charset) instead
static InputStream	toInputStream(String input, String charsetName)	Converts the specified string to an input stream, encoded as bytes using the specified character encoding.
static InputStream	toInputStream(String input, Charset charset)	Converts the specified string to an input stream, encoded as bytes using the specified character encoding.
static String	toString(byte[] input)	Deprecated. Use String(byte[]) instead
static String	toString(byte[] input, String charsetName)	Gets the contents of a byte[] as a String using the specified character encoding.
static String	toString(InputStream input)	Deprecated. Use toString(InputStream, Charset) instead
static String	toString(InputStream input, String charsetName)	Gets the contents of an InputStream as a String using the specified character encoding.
static String	toString(InputStream input, Charset charset)	Gets the contents of an InputStream as a String using the specified character encoding.
static String	toString(Reader reader)	Gets the contents of a Reader as a String.
static String	toString(URI uri)	Deprecated. Use toString(URI, Charset) instead
static String	toString(URI uri, String charsetName)	Gets the contents at the given URI.
static String	toString(URI uri, Charset encoding)	Gets the contents at the given URI.
static String	toString(URL url)	Deprecated. Use toString(URL, Charset) instead
static String	toString(URL url, String charsetName)	Gets the contents at the given URL.
static String	toString(URL url, Charset encoding)	Gets the contents at the given URL.
static String	toString(IOSupplier<InputStream> input, Charset charset)	Gets the contents of an InputStream from a supplier as a String using the specified character encoding.
static String	toString(IOSupplier<InputStream> input, Charset charset, IOSupplier<String> defaultString)	Gets the contents of an InputStream from a supplier as a String using the specified character encoding.
static void	write(byte[] data, OutputStream output)	Writes bytes from a byte[] to an OutputStream.
static void	write(byte[] data, Writer writer)	Deprecated. Use write(byte[], Writer, Charset) instead
static void	write(byte[] data, Writer writer, String charsetName)	Writes bytes from a byte[] to chars on a Writer using the specified character encoding.
static void	write(byte[] data, Writer writer, Charset charset)	Writes bytes from a byte[] to chars on a Writer using the specified character encoding.
static void	write(char[] data, OutputStream output)	Deprecated. Use write(char[], OutputStream, Charset) instead
static void	write(char[] data, OutputStream output, String charsetName)	Writes chars from a char[] to bytes on an OutputStream using the specified character encoding.
static void	write(char[] data, OutputStream output, Charset charset)	Writes chars from a char[] to bytes on an OutputStream using the specified character encoding.
static void	write(char[] data, Writer writer)	Writes chars from a char[] to a Writer
static void	write(CharSequence data, OutputStream output)	Deprecated. Use write(CharSequence, OutputStream, Charset) instead
static void	write(CharSequence data, OutputStream output, String charsetName)	Writes chars from a CharSequence to bytes on an OutputStream using the specified character encoding.
static void	write(CharSequence data, OutputStream output, Charset charset)	Writes chars from a CharSequence to bytes on an OutputStream using the specified character encoding.
static void	write(CharSequence data, Writer writer)	Writes chars from a CharSequence to a Writer.
static void	write(StringBuffer data, OutputStream output)	Deprecated. Use write(CharSequence, OutputStream)
static void	write(StringBuffer data, OutputStream output, String charsetName)	Deprecated. Use write(CharSequence, OutputStream, String).
static void	write(StringBuffer data, Writer writer)	Deprecated. Use write(CharSequence, Writer)
static void	write(String data, OutputStream output)	Deprecated. Use write(String, OutputStream, Charset) instead
static void	write(String data, OutputStream output, String charsetName)	Writes chars from a String to bytes on an OutputStream using the specified character encoding.
static void	write(String data, OutputStream output, Charset charset)	Writes chars from a String to bytes on an OutputStream using the specified character encoding.
static void	write(String data, Writer writer)	Writes chars from a String to a Writer.
static void	writeChunked(byte[] data, OutputStream output)	Writes bytes from a byte[] to an OutputStream using chunked writes.
static void	writeChunked(char[] data, Writer writer)	Writes chars from a char[] to a Writer using chunked writes.
static void	writeLines(Collection<?> lines, String lineEnding, OutputStream output)	Deprecated. Use writeLines(Collection, String, OutputStream, Charset) instead
static void	writeLines(Collection<?> lines, String lineEnding, OutputStream output, String charsetName)	Writes the Object.toString() value of each item in a collection to an OutputStream line by line, using the specified character encoding and the specified line ending.
static void	writeLines(Collection<?> lines, String lineEnding, OutputStream output, Charset charset)	Writes the Object.toString() value of each item in a collection to an OutputStream line by line, using the specified character encoding and the specified line ending.
static void	writeLines(Collection<?> lines, String lineEnding, Writer writer)	Writes the Object.toString() value of each item in a collection to a Writer line by line, using the specified line ending.
static Writer	writer(Appendable appendable)	Returns the given Appendable if it is already a Writer, otherwise creates a Writer wrapper around the given Appendable.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

CR

public static final int CR

CR char '13'.

Since:

2.9.0

See Also:

• Constant Field Values

DEFAULT_BUFFER_SIZE

public static final int DEFAULT_BUFFER_SIZE

The default buffer size (8192) to use in copy methods.

See Also:

• Constant Field Values

DIR_SEPARATOR

public static final char DIR_SEPARATOR

The system directory separator character.

DIR_SEPARATOR_UNIX

public static final char DIR_SEPARATOR_UNIX

The Unix directory separator character ''/''.

See Also:

• Constant Field Values

DIR_SEPARATOR_WINDOWS

public static final char DIR_SEPARATOR_WINDOWS

The Windows directory separator character ''\\''.

See Also:

• Constant Field Values

EMPTY_BYTE_ARRAY

public static final byte[] EMPTY_BYTE_ARRAY

A singleton empty byte array.

Since:

2.9.0

EOF

public static final int EOF

Represents the end-of-file (or stream) value -1.

Since:

2.5 (made public)

See Also:

• Constant Field Values

LF

public static final int LF

LF char '10'.

Since:

2.9.0

See Also:

• Constant Field Values

LINE_SEPARATOR

@Deprecated
public static final String LINE_SEPARATOR

Deprecated.

Use System.lineSeparator().

The system line separator string.

LINE_SEPARATOR_UNIX

public static final String LINE_SEPARATOR_UNIX

The Unix line separator string.

See Also:

• StandardLineSeparator.LF

LINE_SEPARATOR_WINDOWS

public static final String LINE_SEPARATOR_WINDOWS

The Windows line separator string.

See Also:

• StandardLineSeparator.CRLF

Constructor Details

IOUtils

@Deprecated
public IOUtils()

Deprecated.

TODO Make private in 3.0.

Instances should NOT be constructed in standard programming.

Method Details

buffer

public static BufferedInputStream buffer(InputStream inputStream)

Returns the given InputStream if it is already a BufferedInputStream, otherwise creates a BufferedInputStream from the given InputStream.

Parameters:

inputStream - the InputStream to wrap or return (not null)

Returns:

the given InputStream or a new BufferedInputStream for the given InputStream

Throws:

NullPointerException - if the input parameter is null

Since:

2.5

buffer

public static BufferedInputStream buffer(InputStream inputStream,
 int size)

Returns the given InputStream if it is already a BufferedInputStream, otherwise creates a BufferedInputStream from the given InputStream.

Parameters:

inputStream - the InputStream to wrap or return (not null)

size - the buffer size, if a new BufferedInputStream is created.

Returns:

the given InputStream or a new BufferedInputStream for the given InputStream

Throws:

NullPointerException - if the input parameter is null

Since:

2.5

buffer

public static BufferedOutputStream buffer(OutputStream outputStream)

Returns the given OutputStream if it is already a BufferedOutputStream, otherwise creates a BufferedOutputStream from the given OutputStream.

Parameters:

outputStream - the OutputStream to wrap or return (not null)

Returns:

the given OutputStream or a new BufferedOutputStream for the given OutputStream

Throws:

NullPointerException - if the input parameter is null

Since:

2.5

buffer

public static BufferedOutputStream buffer(OutputStream outputStream,
 int size)

Returns the given OutputStream if it is already a BufferedOutputStream, otherwise creates a BufferedOutputStream from the given OutputStream.

Parameters:

outputStream - the OutputStream to wrap or return (not null)

size - the buffer size, if a new BufferedOutputStream is created.

Returns:

the given OutputStream or a new BufferedOutputStream for the given OutputStream

Throws:

NullPointerException - if the input parameter is null

Since:

2.5

buffer

public static BufferedReader buffer(Reader reader)

Returns the given reader if it is already a BufferedReader, otherwise creates a BufferedReader from the given reader.

Parameters:

reader - the reader to wrap or return (not null)

Returns:

the given reader or a new BufferedReader for the given reader

Throws:

NullPointerException - if the input parameter is null

Since:

2.5

buffer

public static BufferedReader buffer(Reader reader,
 int size)

Returns the given reader if it is already a BufferedReader, otherwise creates a BufferedReader from the given reader.

Parameters:

reader - the reader to wrap or return (not null)

size - the buffer size, if a new BufferedReader is created.

Returns:

the given reader or a new BufferedReader for the given reader

Throws:

NullPointerException - if the input parameter is null

Since:

2.5

buffer

public static BufferedWriter buffer(Writer writer)

Returns the given Writer if it is already a BufferedWriter, otherwise creates a BufferedWriter from the given Writer.

Parameters:

writer - the Writer to wrap or return (not null)

Returns:

the given Writer or a new BufferedWriter for the given Writer

Throws:

NullPointerException - if the input parameter is null

Since:

2.5

buffer

public static BufferedWriter buffer(Writer writer,
 int size)

Returns the given Writer if it is already a BufferedWriter, otherwise creates a BufferedWriter from the given Writer.

Parameters:

writer - the Writer to wrap or return (not null)

size - the buffer size, if a new BufferedWriter is created.

Returns:

the given Writer or a new BufferedWriter for the given Writer

Throws:

NullPointerException - if the input parameter is null

Since:

2.5

byteArray

public static byte[] byteArray()

Returns a new byte array of size DEFAULT_BUFFER_SIZE.

Returns:

a new byte array of size DEFAULT_BUFFER_SIZE.

Since:

2.9.0

byteArray

public static byte[] byteArray(int size)

Returns a new byte array of the given size. TODO Consider guarding or warning against large allocations...

Parameters:

size - array size.

Returns:

a new byte array of the given size.

Throws:

NegativeArraySizeException - if the size is negative.

Since:

2.9.0

close

public static void close(Closeable closeable)
                  throws IOException

Closes the given Closeable as a null-safe operation.

Parameters:

closeable - The resource to close, may be null.

Throws:

IOException - if an I/O error occurs.

Since:

2.7

close

public static void close(Closeable... closeables)
                  throws IOExceptionList

Closes the given Closeables as null-safe operations.

Parameters:

closeables - The resource(s) to close, may be null.

Throws:

IOExceptionList - if an I/O error occurs.

Since:

2.8.0

close

public static void close(Closeable closeable,
 IOConsumer<IOException> consumer)
                  throws IOException

Closes the given Closeable as a null-safe operation.

Parameters:

closeable - The resource to close, may be null.

consumer - Consume the IOException thrown by Closeable.close().

Throws:

IOException - if an I/O error occurs.

Since:

2.7

close

public static void close(URLConnection conn)

Closes a URLConnection.

Parameters:

conn - the connection to close.

Since:

2.4

closeQuietly

public static void closeQuietly(Closeable closeable)

Closes a Closeable unconditionally.

Equivalent to Closeable.close(), except any exceptions will be ignored. This is typically used in finally blocks.

Example code:

 Closeable closeable = null;
 try {
     closeable = new FileReader("foo.txt");
     // process closeable
     closeable.close();
 } catch (Exception e) {
     // error handling
 } finally {
     IOUtils.closeQuietly(closeable);
 }
 

Closing all streams:

 try {
     return IOUtils.copy(inputStream, outputStream);
 } finally {
     IOUtils.closeQuietly(inputStream);
     IOUtils.closeQuietly(outputStream);
 }
 

Also consider using a try-with-resources statement where appropriate.

Parameters:

closeable - the objects to close, may be null or already closed

Since:

2.0

See Also:

• Throwable.addSuppressed(Throwable)

closeQuietly

public static void closeQuietly(Closeable... closeables)

Closes a Closeable unconditionally.

Equivalent to Closeable.close(), except any exceptions will be ignored.

This is typically used in finally blocks to ensure that the closeable is closed even if an Exception was thrown before the normal close statement was reached.
It should not be used to replace the close statement(s) which should be present for the non-exceptional case.
It is only intended to simplify tidying up where normal processing has already failed and reporting close failure as well is not necessary or useful.

Example code:

 Closeable closeable = null;
 try {
     closeable = new FileReader("foo.txt");
     // processing using the closeable; may throw an Exception
     closeable.close(); // Normal close - exceptions not ignored
 } catch (Exception e) {
     // error handling
 } finally {
     IOUtils.closeQuietly(closeable); // In case normal close was skipped due to Exception
 }
 

Closing all streams:

 try {
     return IOUtils.copy(inputStream, outputStream);
 } finally {
     IOUtils.closeQuietly(inputStream, outputStream);
 }
 

Also consider using a try-with-resources statement where appropriate.

Parameters:

closeables - the objects to close, may be null or already closed

Since:

2.5

See Also:

• closeQuietly(Closeable)
• Throwable.addSuppressed(Throwable)

closeQuietly

public static void closeQuietly(Closeable closeable,
 Consumer<Exception> consumer)

Closes the given Closeable as a null-safe operation while consuming IOException by the given consumer.

Parameters:

closeable - The resource to close, may be null.

consumer - Consumes the Exception thrown by Closeable.close().

Since:

2.7

closeQuietly

public static void closeQuietly(InputStream input)

Closes an InputStream unconditionally.

Equivalent to InputStream.close(), except any exceptions will be ignored. This is typically used in finally blocks.

Example code:

   byte[] data = new byte[1024];
   InputStream in = null;
   try {
       in = new FileInputStream("foo.txt");
       in.read(data);
       in.close(); //close errors are handled
   } catch (Exception e) {
       // error handling
   } finally {
       IOUtils.closeQuietly(in);
   }
 

Also consider using a try-with-resources statement where appropriate.

Parameters:

input - the InputStream to close, may be null or already closed

See Also:

• Throwable.addSuppressed(Throwable)

closeQuietly

public static void closeQuietly(Iterable<Closeable> closeables)

Closes an iterable of Closeable unconditionally.

Equivalent calling Closeable.close() on each element, except any exceptions will be ignored.

Parameters:

closeables - the objects to close, may be null or already closed

Since:

2.12.0

See Also:

• closeQuietly(Closeable)

closeQuietly

public static void closeQuietly(OutputStream output)

Closes an OutputStream unconditionally.

Equivalent to OutputStream.close(), except any exceptions will be ignored. This is typically used in finally blocks.

Example code:

 byte[] data = "Hello, World".getBytes();

 OutputStream out = null;
 try {
     out = new FileOutputStream("foo.txt");
     out.write(data);
     out.close(); //close errors are handled
 } catch (IOException e) {
     // error handling
 } finally {
     IOUtils.closeQuietly(out);
 }
 

Also consider using a try-with-resources statement where appropriate.

Parameters:

output - the OutputStream to close, may be null or already closed

See Also:

• Throwable.addSuppressed(Throwable)

closeQuietly

public static void closeQuietly(Reader reader)

Closes an Reader unconditionally.

Equivalent to Reader.close(), except any exceptions will be ignored. This is typically used in finally blocks.

Example code:

   char[] data = new char[1024];
   Reader in = null;
   try {
       in = new FileReader("foo.txt");
       in.read(data);
       in.close(); //close errors are handled
   } catch (Exception e) {
       // error handling
   } finally {
       IOUtils.closeQuietly(in);
   }
 

Also consider using a try-with-resources statement where appropriate.

Parameters:

reader - the Reader to close, may be null or already closed

See Also:

• Throwable.addSuppressed(Throwable)

closeQuietly

public static void closeQuietly(Selector selector)

Closes a Selector unconditionally.

Equivalent to Selector.close(), except any exceptions will be ignored. This is typically used in finally blocks.

Example code:

   Selector selector = null;
   try {
       selector = Selector.open();
       // process socket

   } catch (Exception e) {
       // error handling
   } finally {
       IOUtils.closeQuietly(selector);
   }
 

Also consider using a try-with-resources statement where appropriate.

Parameters:

selector - the Selector to close, may be null or already closed

Since:

2.2

See Also:

• Throwable.addSuppressed(Throwable)

closeQuietly

public static void closeQuietly(ServerSocket serverSocket)

Closes a ServerSocket unconditionally.

Equivalent to ServerSocket.close(), except any exceptions will be ignored. This is typically used in finally blocks.

Example code:

   ServerSocket socket = null;
   try {
       socket = new ServerSocket();
       // process socket
       socket.close();
   } catch (Exception e) {
       // error handling
   } finally {
       IOUtils.closeQuietly(socket);
   }
 

Also consider using a try-with-resources statement where appropriate.

Parameters:

serverSocket - the ServerSocket to close, may be null or already closed

Since:

2.2

See Also:

• Throwable.addSuppressed(Throwable)

closeQuietly

public static void closeQuietly(Socket socket)

Closes a Socket unconditionally.

Equivalent to Socket.close(), except any exceptions will be ignored. This is typically used in finally blocks.

Example code:

   Socket socket = null;
   try {
       socket = new Socket("http://www.foo.com/", 80);
       // process socket
       socket.close();
   } catch (Exception e) {
       // error handling
   } finally {
       IOUtils.closeQuietly(socket);
   }
 

Also consider using a try-with-resources statement where appropriate.

Parameters:

socket - the Socket to close, may be null or already closed

Since:

2.0

See Also:

• Throwable.addSuppressed(Throwable)

closeQuietly

public static void closeQuietly(Stream<Closeable> closeables)

Closes a stream of Closeable unconditionally.

Equivalent calling Closeable.close() on each element, except any exceptions will be ignored.

Parameters:

closeables - the objects to close, may be null or already closed

Since:

2.12.0

See Also:

• closeQuietly(Closeable)

closeQuietly

public static void closeQuietly(Writer writer)

Closes an Writer unconditionally.

Equivalent to Writer.close(), except any exceptions will be ignored. This is typically used in finally blocks.

Example code:

   Writer out = null;
   try {
       out = new StringWriter();
       out.write("Hello World");
       out.close(); //close errors are handled
   } catch (Exception e) {
       // error handling
   } finally {
       IOUtils.closeQuietly(out);
   }
 

Also consider using a try-with-resources statement where appropriate.

Parameters:

writer - the Writer to close, may be null or already closed

See Also:

• Throwable.addSuppressed(Throwable)

consume

public static long consume(InputStream input)
                    throws IOException

Consumes bytes from a InputStream and ignores them.

The buffer size is given by DEFAULT_BUFFER_SIZE.

Parameters:

input - the InputStream to read.

Returns:

the number of bytes copied. or 0 if input is null.

Throws:

NullPointerException - if the InputStream is null.

IOException - if an I/O error occurs.

Since:

2.8.0

consume

public static long consume(Reader input)
                    throws IOException

Consumes characters from a Reader and ignores them.

The buffer size is given by DEFAULT_BUFFER_SIZE.

Parameters:

input - the Reader to read.

Returns:

the number of bytes copied. or 0 if input is null.

Throws:

NullPointerException - if the Reader is null.

IOException - if an I/O error occurs.

Since:

2.12.0

contentEquals

public static boolean contentEquals(InputStream input1,
 InputStream input2)
                             throws IOException

Compares the contents of two Streams to determine if they are equal or not.

This method buffers the input internally using BufferedInputStream if they are not already buffered.

Parameters:

input1 - the first stream

input2 - the second stream

Returns:

true if the content of the streams are equal or they both don't exist, false otherwise

Throws:

IOException - if an I/O error occurs

contentEquals

public static boolean contentEquals(Reader input1,
 Reader input2)
                             throws IOException

Compares the contents of two Readers to determine if they are equal or not.

This method buffers the input internally using BufferedReader if they are not already buffered.

Parameters:

input1 - the first reader

input2 - the second reader

Returns:

true if the content of the readers are equal or they both don't exist, false otherwise

Throws:

NullPointerException - if either input is null

IOException - if an I/O error occurs

Since:

1.1

contentEqualsIgnoreEOL

public static boolean contentEqualsIgnoreEOL(Reader reader1,
 Reader reader2)
                                      throws UncheckedIOException

Compares the contents of two Readers to determine if they are equal or not, ignoring EOL characters.

This method buffers the input internally using BufferedReader if they are not already buffered.

Parameters:

reader1 - the first reader

reader2 - the second reader

Returns:

true if the content of the readers are equal (ignoring EOL differences), false otherwise

Throws:

NullPointerException - if either input is null

UncheckedIOException - if an I/O error occurs

Since:

2.2

copy

public static int copy(InputStream inputStream,
 OutputStream outputStream)
                throws IOException

Copies bytes from an InputStream to an OutputStream.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Large streams (over 2GB) will return a bytes copied value of -1 after the copy has completed since the correct number of bytes cannot be returned as an int. For large streams use the copyLarge(InputStream, OutputStream) method.

Parameters:

inputStream - the InputStream to read.

outputStream - the OutputStream to write.

Returns:

the number of bytes copied, or -1 if greater than Integer.MAX_VALUE.

Throws:

NullPointerException - if the InputStream is null.

NullPointerException - if the OutputStream is null.

IOException - if an I/O error occurs.

Since:

1.1

copy

public static long copy(InputStream inputStream,
 OutputStream outputStream,
 int bufferSize)
                 throws IOException

Copies bytes from an InputStream to an OutputStream using an internal buffer of the given size.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

inputStream - the InputStream to read.

outputStream - the OutputStream to write to

bufferSize - the bufferSize used to copy from the input to the output

Returns:

the number of bytes copied.

Throws:

NullPointerException - if the InputStream is null.

NullPointerException - if the OutputStream is null.

IOException - if an I/O error occurs.

Since:

2.5

copy

@Deprecated
public static void copy(InputStream input,
 Writer writer)
                 throws IOException

Deprecated.

Use copy(InputStream, Writer, Charset) instead

Copies bytes from an InputStream to chars on a Writer using the virtual machine's default charset.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

This method uses InputStreamReader.

Parameters:

input - the InputStream to read

writer - the Writer to write to

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

1.1

copy

public static void copy(InputStream input,
 Writer writer,
 Charset inputCharset)
                 throws IOException

Copies bytes from an InputStream to chars on a Writer using the specified character encoding.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

This method uses InputStreamReader.

Parameters:

input - the InputStream to read

writer - the Writer to write to

inputCharset - the charset to use for the input stream, null means platform default

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

2.3

copy

public static void copy(InputStream input,
 Writer writer,
 String inputCharsetName)
                 throws IOException

Copies bytes from an InputStream to chars on a Writer using the specified character encoding.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Character encoding names can be found at IANA.

This method uses InputStreamReader.

Parameters:

input - the InputStream to read

writer - the Writer to write to

inputCharsetName - the name of the requested charset for the InputStream, null means platform default

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

UnsupportedCharsetException - if the encoding is not supported

Since:

1.1

copy

public static QueueInputStream copy(ByteArrayOutputStream outputStream)
                             throws IOException

Copies bytes from a ByteArrayOutputStream to a QueueInputStream.

Unlike using JDK PipedInputStream and PipedOutputStream for this, this solution works safely in a single thread environment.

Example usage:

 ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
 outputStream.writeBytes("hello world".getBytes(StandardCharsets.UTF_8));

 InputStream inputStream = IOUtils.copy(outputStream);
 

Parameters:

outputStream - the ByteArrayOutputStream to read.

Returns:

the QueueInputStream filled with the content of the outputStream.

Throws:

NullPointerException - if the ByteArrayOutputStream is null.

IOException - if an I/O error occurs.

Since:

2.12

copy

public static long copy(Reader reader,
 Appendable output)
                 throws IOException

Copies chars from a Reader to a Appendable.

This method buffers the input internally, so there is no need to use a BufferedReader.

Large streams (over 2GB) will return a chars copied value of -1 after the copy has completed since the correct number of chars cannot be returned as an int. For large streams use the copyLarge(Reader, Writer) method.

Parameters:

reader - the Reader to read

output - the Appendable to write to

Returns:

the number of characters copied, or -1 if > Integer.MAX_VALUE

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

2.7

copy

public static long copy(Reader reader,
 Appendable output,
 CharBuffer buffer)
                 throws IOException

Copies chars from a Reader to an Appendable.

This method uses the provided buffer, so there is no need to use a BufferedReader.

Parameters:

reader - the Reader to read

output - the Appendable to write to

buffer - the buffer to be used for the copy

Returns:

the number of characters copied

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

2.7

copy

@Deprecated
public static void copy(Reader reader,
 OutputStream output)
                 throws IOException

Deprecated.

Use copy(Reader, OutputStream, Charset) instead

Copies chars from a Reader to bytes on an OutputStream using the the virtual machine's default charset, and calling flush.

This method buffers the input internally, so there is no need to use a BufferedReader.

Due to the implementation of OutputStreamWriter, this method performs a flush.

This method uses OutputStreamWriter.

Parameters:

reader - the Reader to read

output - the OutputStream to write to

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

1.1

copy

public static void copy(Reader reader,
 OutputStream output,
 Charset outputCharset)
                 throws IOException

Copies chars from a Reader to bytes on an OutputStream using the specified character encoding, and calling flush.

This method buffers the input internally, so there is no need to use a BufferedReader.

Due to the implementation of OutputStreamWriter, this method performs a flush.

This method uses OutputStreamWriter.

Parameters:

reader - the Reader to read

output - the OutputStream to write to

outputCharset - the charset to use for the OutputStream, null means platform default

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

2.3

copy

public static void copy(Reader reader,
 OutputStream output,
 String outputCharsetName)
                 throws IOException

Copies chars from a Reader to bytes on an OutputStream using the specified character encoding, and calling flush.

This method buffers the input internally, so there is no need to use a BufferedReader.

Character encoding names can be found at IANA.

Due to the implementation of OutputStreamWriter, this method performs a flush.

This method uses OutputStreamWriter.

Parameters:

reader - the Reader to read

output - the OutputStream to write to

outputCharsetName - the name of the requested charset for the OutputStream, null means platform default

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

UnsupportedCharsetException - if the encoding is not supported

Since:

1.1

copy

public static int copy(Reader reader,
 Writer writer)
                throws IOException

Copies chars from a Reader to a Writer.

This method buffers the input internally, so there is no need to use a BufferedReader.

Large streams (over 2GB) will return a chars copied value of -1 after the copy has completed since the correct number of chars cannot be returned as an int. For large streams use the copyLarge(Reader, Writer) method.

Parameters:

reader - the Reader to read.

writer - the Writer to write.

Returns:

the number of characters copied, or -1 if > Integer.MAX_VALUE

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

1.1

copy

public static long copy(URL url,
 File file)
                 throws IOException

Copies bytes from a URL to an OutputStream.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

The buffer size is given by DEFAULT_BUFFER_SIZE.

Parameters:

url - the URL to read.

file - the OutputStream to write.

Returns:

the number of bytes copied.

Throws:

NullPointerException - if the URL is null.

NullPointerException - if the OutputStream is null.

IOException - if an I/O error occurs.

Since:

2.9.0

copy

public static long copy(URL url,
 OutputStream outputStream)
                 throws IOException

Copies bytes from a URL to an OutputStream.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

The buffer size is given by DEFAULT_BUFFER_SIZE.

Parameters:

url - the URL to read.

outputStream - the OutputStream to write.

Returns:

the number of bytes copied.

Throws:

NullPointerException - if the URL is null.

NullPointerException - if the OutputStream is null.

IOException - if an I/O error occurs.

Since:

2.9.0

copyLarge

public static long copyLarge(InputStream inputStream,
 OutputStream outputStream)
                      throws IOException

Copies bytes from a large (over 2GB) InputStream to an OutputStream.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

The buffer size is given by DEFAULT_BUFFER_SIZE.

Parameters:

inputStream - the InputStream to read.

outputStream - the OutputStream to write.

Returns:

the number of bytes copied.

Throws:

NullPointerException - if the InputStream is null.

NullPointerException - if the OutputStream is null.

IOException - if an I/O error occurs.

Since:

1.3

copyLarge

public static long copyLarge(InputStream inputStream,
 OutputStream outputStream,
 byte[] buffer)
                      throws IOException

Copies bytes from a large (over 2GB) InputStream to an OutputStream.

This method uses the provided buffer, so there is no need to use a BufferedInputStream.

Parameters:

inputStream - the InputStream to read.

outputStream - the OutputStream to write.

buffer - the buffer to use for the copy

Returns:

the number of bytes copied.

Throws:

NullPointerException - if the InputStream is null.

NullPointerException - if the OutputStream is null.

IOException - if an I/O error occurs.

Since:

2.2

copyLarge

public static long copyLarge(InputStream input,
 OutputStream output,
 long inputOffset,
 long length)
                      throws IOException

Copies some or all bytes from a large (over 2GB) InputStream to an OutputStream, optionally skipping input bytes.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Note that the implementation uses skip(InputStream, long). This means that the method may be considerably less efficient than using the actual skip implementation, this is done to guarantee that the correct number of characters are skipped.

The buffer size is given by DEFAULT_BUFFER_SIZE.

Parameters:

input - the InputStream to read.

output - the OutputStream to write.

inputOffset - number of bytes to skip from input before copying, these bytes are ignored.

length - number of bytes to copy.

Returns:

the number of bytes copied.

Throws:

NullPointerException - if the input or output is null.

IOException - if an I/O error occurs.

Since:

2.2

copyLarge

public static long copyLarge(InputStream input,
 OutputStream output,
 long inputOffset,
 long length,
 byte[] buffer)
                      throws IOException

Copies some or all bytes from a large (over 2GB) InputStream to an OutputStream, optionally skipping input bytes.

This method uses the provided buffer, so there is no need to use a BufferedInputStream.

Note that the implementation uses skip(InputStream, long). This means that the method may be considerably less efficient than using the actual skip implementation, this is done to guarantee that the correct number of characters are skipped.

Parameters:

input - the InputStream to read.

output - the OutputStream to write.

inputOffset - number of bytes to skip from input before copying, these bytes are ignored.

length - number of bytes to copy.

buffer - the buffer to use for the copy.

Returns:

the number of bytes copied.

Throws:

NullPointerException - if the input or output is null.

IOException - if an I/O error occurs.

Since:

2.2

copyLarge

public static long copyLarge(Reader reader,
 Writer writer)
                      throws IOException

Copies chars from a large (over 2GB) Reader to a Writer.

This method buffers the input internally, so there is no need to use a BufferedReader.

The buffer size is given by DEFAULT_BUFFER_SIZE.

Parameters:

reader - the Reader to source.

writer - the Writer to target.

Returns:

the number of characters copied

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

1.3

copyLarge

public static long copyLarge(Reader reader,
 Writer writer,
 char[] buffer)
                      throws IOException

Copies chars from a large (over 2GB) Reader to a Writer.

This method uses the provided buffer, so there is no need to use a BufferedReader.

Parameters:

reader - the Reader to source.

writer - the Writer to target.

buffer - the buffer to be used for the copy

Returns:

the number of characters copied

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

2.2

copyLarge

public static long copyLarge(Reader reader,
 Writer writer,
 long inputOffset,
 long length)
                      throws IOException

Copies some or all chars from a large (over 2GB) InputStream to an OutputStream, optionally skipping input chars.

This method buffers the input internally, so there is no need to use a BufferedReader.

The buffer size is given by DEFAULT_BUFFER_SIZE.

Parameters:

reader - the Reader to read

writer - the Writer to write to

inputOffset - number of chars to skip from input before copying -ve values are ignored

length - number of chars to copy. -ve means all

Returns:

the number of chars copied

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

2.2

copyLarge

public static long copyLarge(Reader reader,
 Writer writer,
 long inputOffset,
 long length,
 char[] buffer)
                      throws IOException

Copies some or all chars from a large (over 2GB) InputStream to an OutputStream, optionally skipping input chars.

This method uses the provided buffer, so there is no need to use a BufferedReader.

Parameters:

reader - the Reader to read

writer - the Writer to write to

inputOffset - number of chars to skip from input before copying -ve values are ignored

length - number of chars to copy. -ve means all

buffer - the buffer to be used for the copy

Returns:

the number of chars copied

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

2.2

length

public static int length(byte[] array)

Returns the length of the given array in a null-safe manner.

Parameters:

array - an array or null

Returns:

the array length, or 0 if the given array is null.

Since:

2.7

length

public static int length(char[] array)

Returns the length of the given array in a null-safe manner.

Parameters:

array - an array or null

Returns:

the array length, or 0 if the given array is null.

Since:

2.7

length

public static int length(CharSequence csq)

Returns the length of the given CharSequence in a null-safe manner.

Parameters:

csq - a CharSequence or null

Returns:

the CharSequence length, or 0 if the given CharSequence is null.

Since:

2.7

length

public static int length(Object[] array)

Returns the length of the given array in a null-safe manner.

Parameters:

array - an array or null

Returns:

the array length, or 0 if the given array is null.

Since:

2.7

lineIterator

public static LineIterator lineIterator(InputStream input,
 Charset charset)

Returns an Iterator for the lines in an InputStream, using the character encoding specified (or default encoding if null).

LineIterator holds a reference to the open InputStream specified here. When you have finished with the iterator you should close the stream to free internal resources. This can be done by using a try-with-resources block, closing the stream directly, or by calling LineIterator.close().

The recommended usage pattern is:

 try {
   LineIterator it = IOUtils.lineIterator(stream, charset);
   while (it.hasNext()) {
     String line = it.nextLine();
     /// do something with line
   }
 } finally {
   IOUtils.closeQuietly(stream);
 }
 

Parameters:

input - the InputStream to read, not null

charset - the charset to use, null means platform default

Returns:

an Iterator of the lines in the reader, never null

Throws:

IllegalArgumentException - if the input is null

Since:

2.3

lineIterator

public static LineIterator lineIterator(InputStream input,
 String charsetName)

Returns an Iterator for the lines in an InputStream, using the character encoding specified (or default encoding if null).

LineIterator holds a reference to the open InputStream specified here. When you have finished with the iterator you should close the stream to free internal resources. This can be done by using a try-with-resources block, closing the stream directly, or by calling LineIterator.close().

The recommended usage pattern is:

 try {
   LineIterator it = IOUtils.lineIterator(stream, StandardCharsets.UTF_8.name());
   while (it.hasNext()) {
     String line = it.nextLine();
     /// do something with line
   }
 } finally {
   IOUtils.closeQuietly(stream);
 }
 

Parameters:

input - the InputStream to read, not null

charsetName - the encoding to use, null means platform default

Returns:

an Iterator of the lines in the reader, never null

Throws:

IllegalArgumentException - if the input is null

UnsupportedCharsetException - if the encoding is not supported

Since:

1.2

lineIterator

public static LineIterator lineIterator(Reader reader)

Returns an Iterator for the lines in a Reader.

LineIterator holds a reference to the open Reader specified here. When you have finished with the iterator you should close the reader to free internal resources. This can be done by using a try-with-resources block, closing the reader directly, or by calling LineIterator.close().

The recommended usage pattern is:

 try {
   LineIterator it = IOUtils.lineIterator(reader);
   while (it.hasNext()) {
     String line = it.nextLine();
     /// do something with line
   }
 } finally {
   IOUtils.closeQuietly(reader);
 }
 

Parameters:

reader - the Reader to read, not null

Returns:

an Iterator of the lines in the reader, never null

Throws:

NullPointerException - if the reader is null

Since:

1.2

read

public static int read(InputStream input,
 byte[] buffer)
                throws IOException

Reads bytes from an input stream. This implementation guarantees that it will read as many bytes as possible before giving up; this may not always be the case for subclasses of InputStream.

Parameters:

input - where to read input from

buffer - destination

Returns:

actual length read; may be less than requested if EOF was reached

Throws:

IOException - if a read error occurs

Since:

2.2

read

public static int read(InputStream input,
 byte[] buffer,
 int offset,
 int length)
                throws IOException

Reads bytes from an input stream. This implementation guarantees that it will read as many bytes as possible before giving up; this may not always be the case for subclasses of InputStream.

Parameters:

input - where to read input

buffer - destination

offset - initial offset into buffer

length - length to read, must be >= 0

Returns:

actual length read; may be less than requested if EOF was reached

Throws:

IllegalArgumentException - if length is negative

IOException - if a read error occurs

Since:

2.2

read

public static int read(ReadableByteChannel input,
 ByteBuffer buffer)
                throws IOException

Reads bytes from a ReadableByteChannel.

This implementation guarantees that it will read as many bytes as possible before giving up; this may not always be the case for subclasses of ReadableByteChannel.

Parameters:

input - the byte channel to read

buffer - byte buffer destination

Returns:

the actual length read; may be less than requested if EOF was reached

Throws:

IOException - if a read error occurs

Since:

2.5

read

public static int read(Reader reader,
 char[] buffer)
                throws IOException

Reads characters from an input character stream. This implementation guarantees that it will read as many characters as possible before giving up; this may not always be the case for subclasses of Reader.

Parameters:

reader - where to read input from

buffer - destination

Returns:

actual length read; may be less than requested if EOF was reached

Throws:

IOException - if a read error occurs

Since:

2.2

read

public static int read(Reader reader,
 char[] buffer,
 int offset,
 int length)
                throws IOException

Reads characters from an input character stream. This implementation guarantees that it will read as many characters as possible before giving up; this may not always be the case for subclasses of Reader.

Parameters:

reader - where to read input from

buffer - destination

offset - initial offset into buffer

length - length to read, must be >= 0

Returns:

actual length read; may be less than requested if EOF was reached

Throws:

IllegalArgumentException - if length is negative

IOException - if a read error occurs

Since:

2.2

readFully

public static void readFully(InputStream input,
 byte[] buffer)
                      throws IOException

Reads the requested number of bytes or fail if there are not enough left.

This allows for the possibility that InputStream.read(byte[], int, int) may not read as many bytes as requested (most likely because of reaching EOF).

Parameters:

input - where to read input from

buffer - destination

Throws:

IOException - if there is a problem reading the file

IllegalArgumentException - if length is negative

EOFException - if the number of bytes read was incorrect

Since:

2.2

readFully

public static void readFully(InputStream input,
 byte[] buffer,
 int offset,
 int length)
                      throws IOException

Reads the requested number of bytes or fail if there are not enough left.

This allows for the possibility that InputStream.read(byte[], int, int) may not read as many bytes as requested (most likely because of reaching EOF).

Parameters:

input - where to read input from

buffer - destination

offset - initial offset into buffer

length - length to read, must be >= 0

Throws:

IOException - if there is a problem reading the file

IllegalArgumentException - if length is negative

EOFException - if the number of bytes read was incorrect

Since:

2.2

readFully

public static byte[] readFully(InputStream input,
 int length)
                        throws IOException

Reads the requested number of bytes or fail if there are not enough left.

This allows for the possibility that InputStream.read(byte[], int, int) may not read as many bytes as requested (most likely because of reaching EOF).

Parameters:

input - where to read input from

length - length to read, must be >= 0

Returns:

the bytes read from input

Throws:

IOException - if there is a problem reading the file

IllegalArgumentException - if length is negative

EOFException - if the number of bytes read was incorrect

Since:

2.5

readFully

public static void readFully(ReadableByteChannel input,
 ByteBuffer buffer)
                      throws IOException

Reads the requested number of bytes or fail if there are not enough left.

This allows for the possibility that ReadableByteChannel.read(ByteBuffer) may not read as many bytes as requested (most likely because of reaching EOF).

Parameters:

input - the byte channel to read

buffer - byte buffer destination

Throws:

IOException - if there is a problem reading the file

EOFException - if the number of bytes read was incorrect

Since:

2.5

readFully

public static void readFully(Reader reader,
 char[] buffer)
                      throws IOException

Reads the requested number of characters or fail if there are not enough left.

This allows for the possibility that Reader.read(char[], int, int) may not read as many characters as requested (most likely because of reaching EOF).

Parameters:

reader - where to read input from

buffer - destination

Throws:

IOException - if there is a problem reading the file

IllegalArgumentException - if length is negative

EOFException - if the number of characters read was incorrect

Since:

2.2

readFully

public static void readFully(Reader reader,
 char[] buffer,
 int offset,
 int length)
                      throws IOException

Reads the requested number of characters or fail if there are not enough left.

This allows for the possibility that Reader.read(char[], int, int) may not read as many characters as requested (most likely because of reaching EOF).

Parameters:

reader - where to read input from

buffer - destination

offset - initial offset into buffer

length - length to read, must be >= 0

Throws:

IOException - if there is a problem reading the file

IllegalArgumentException - if length is negative

EOFException - if the number of characters read was incorrect

Since:

2.2

readLines

public static List<String> readLines(CharSequence csq)
                              throws UncheckedIOException

Gets the contents of a CharSequence as a list of Strings, one entry per line.

Parameters:

csq - the CharSequence to read, not null

Returns:

the list of Strings, never null

Throws:

UncheckedIOException - if an I/O error occurs

Since:

2.18.0

readLines

@Deprecated
public static List<String> readLines(InputStream input)
                              throws UncheckedIOException

Deprecated.

Use readLines(InputStream, Charset) instead

Gets the contents of an InputStream as a list of Strings, one entry per line, using the virtual machine's default charset.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - the InputStream to read, not null

Returns:

the list of Strings, never null

Throws:

NullPointerException - if the input is null

UncheckedIOException - if an I/O error occurs

Since:

1.1

readLines

public static List<String> readLines(InputStream input,
 Charset charset)
                              throws UncheckedIOException

Gets the contents of an InputStream as a list of Strings, one entry per line, using the specified character encoding.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - the InputStream to read, not null

charset - the charset to use, null means platform default

Returns:

the list of Strings, never null

Throws:

NullPointerException - if the input is null

UncheckedIOException - if an I/O error occurs

Since:

2.3

readLines

public static List<String> readLines(InputStream input,
 String charsetName)
                              throws UncheckedIOException

Gets the contents of an InputStream as a list of Strings, one entry per line, using the specified character encoding.

Character encoding names can be found at IANA.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - the InputStream to read, not null

charsetName - the name of the requested charset, null means platform default

Returns:

the list of Strings, never null

Throws:

NullPointerException - if the input is null

UncheckedIOException - if an I/O error occurs

UnsupportedCharsetException - if the encoding is not supported

Since:

1.1

readLines

public static List<String> readLines(Reader reader)
                              throws UncheckedIOException

Gets the contents of a Reader as a list of Strings, one entry per line.

This method buffers the input internally, so there is no need to use a BufferedReader.

Parameters:

reader - the Reader to read, not null

Returns:

the list of Strings, never null

Throws:

NullPointerException - if the input is null

UncheckedIOException - if an I/O error occurs

Since:

1.1

resourceToByteArray

public static byte[] resourceToByteArray(String name)
                                  throws IOException

Gets the contents of a resource as a byte array.

Delegates to resourceToByteArray(String, null).

Parameters:

name - The resource name.

Returns:

the requested byte array

Throws:

IOException - if an I/O error occurs or the resource is not found.

Since:

2.6

See Also:

• resourceToByteArray(String, ClassLoader)

resourceToByteArray

public static byte[] resourceToByteArray(String name,
 ClassLoader classLoader)
                                  throws IOException

Gets the contents of a resource as a byte array.

Delegates to resourceToURL(String, ClassLoader).

Parameters:

name - The resource name.

classLoader - the class loader that the resolution of the resource is delegated to

Returns:

the requested byte array

Throws:

IOException - if an I/O error occurs or the resource is not found.

Since:

2.6

See Also:

• resourceToURL(String, ClassLoader)

resourceToString

public static String resourceToString(String name,
 Charset charset)
                               throws IOException

Gets the contents of a resource as a String using the specified character encoding.

Delegates to resourceToString(String, Charset, null).

Parameters:

name - The resource name.

charset - the charset to use, null means platform default

Returns:

the requested String

Throws:

IOException - if an I/O error occurs or the resource is not found.

Since:

2.6

See Also:

• resourceToString(String, Charset, ClassLoader)

resourceToString

public static String resourceToString(String name,
 Charset charset,
 ClassLoader classLoader)
                               throws IOException

Gets the contents of a resource as a String using the specified character encoding.

Delegates to resourceToURL(String, ClassLoader).

Parameters:

name - The resource name.

charset - the Charset to use, null means platform default

classLoader - the class loader that the resolution of the resource is delegated to

Returns:

the requested String

Throws:

IOException - if an I/O error occurs.

Since:

2.6

See Also:

• resourceToURL(String, ClassLoader)

resourceToURL

public static URL resourceToURL(String name)
                         throws IOException

Gets a URL pointing to the given resource.

Delegates to resourceToURL(String, null).

Parameters:

name - The resource name.

Returns:

A URL object for reading the resource.

Throws:

IOException - if the resource is not found.

Since:

2.6

resourceToURL

public static URL resourceToURL(String name,
 ClassLoader classLoader)
                         throws IOException

Gets a URL pointing to the given resource.

If the classLoader is not null, call ClassLoader.getResource(String), otherwise call IOUtils.class.getResource(name).

Parameters:

name - The resource name.

classLoader - Delegate to this class loader if not null

Returns:

A URL object for reading the resource.

Throws:

IOException - if the resource is not found.

Since:

2.6

skip

public static long skip(InputStream input,
 long skip)
                 throws IOException

Skips bytes from an input byte stream. This implementation guarantees that it will read as many bytes as possible before giving up; this may not always be the case for skip() implementations in subclasses of InputStream.

Note that the implementation uses InputStream.read(byte[], int, int) rather than delegating to InputStream.skip(long). This means that the method may be considerably less efficient than using the actual skip implementation, this is done to guarantee that the correct number of bytes are skipped.

Parameters:

input - byte stream to skip

skip - number of bytes to skip.

Returns:

number of bytes actually skipped.

Throws:

IOException - if there is a problem reading the file

IllegalArgumentException - if toSkip is negative

Since:

2.0

See Also:

• InputStream.skip(long)
• IO-203 - Add skipFully() method for InputStreams

skip

public static long skip(InputStream input,
 long skip,
 Supplier<byte[]> skipBufferSupplier)
                 throws IOException

Skips bytes from an input byte stream.

Intended for special cases when customization of the temporary buffer is needed because, for example, a nested input stream has requirements for the bytes read. For example, when using InflaterInputStreams from multiple threads.

This implementation guarantees that it will read as many bytes as possible before giving up; this may not always be the case for skip() implementations in subclasses of InputStream.

Note that the implementation uses InputStream.read(byte[], int, int) rather than delegating to InputStream.skip(long). This means that the method may be considerably less efficient than using the actual skip implementation, this is done to guarantee that the correct number of bytes are skipped.

Parameters:

input - byte stream to skip

skip - number of bytes to skip.

skipBufferSupplier - Supplies the buffer to use for reading.

Returns:

number of bytes actually skipped.

Throws:

IOException - if there is a problem reading the file

IllegalArgumentException - if toSkip is negative

Since:

2.14.0

See Also:

• InputStream.skip(long)
• IO-203 - Add skipFully() method for InputStreams

skip

public static long skip(ReadableByteChannel input,
 long toSkip)
                 throws IOException

Skips bytes from a ReadableByteChannel. This implementation guarantees that it will read as many bytes as possible before giving up.

Parameters:

input - ReadableByteChannel to skip

toSkip - number of bytes to skip.

Returns:

number of bytes actually skipped.

Throws:

IOException - if there is a problem reading the ReadableByteChannel

IllegalArgumentException - if toSkip is negative

Since:

2.5

skip

public static long skip(Reader reader,
 long toSkip)
                 throws IOException

Skips characters from an input character stream. This implementation guarantees that it will read as many characters as possible before giving up; this may not always be the case for skip() implementations in subclasses of Reader.

Note that the implementation uses Reader.read(char[], int, int) rather than delegating to Reader.skip(long). This means that the method may be considerably less efficient than using the actual skip implementation, this is done to guarantee that the correct number of characters are skipped.

Parameters:

reader - character stream to skip

toSkip - number of characters to skip.

Returns:

number of characters actually skipped.

Throws:

IOException - if there is a problem reading the file

IllegalArgumentException - if toSkip is negative

Since:

2.0

See Also:

• Reader.skip(long)
• IO-203 - Add skipFully() method for InputStreams

skipFully

public static void skipFully(InputStream input,
 long toSkip)
                      throws IOException

Skips the requested number of bytes or fail if there are not enough left.

This allows for the possibility that InputStream.skip(long) may not skip as many bytes as requested (most likely because of reaching EOF).

Note that the implementation uses skip(InputStream, long). This means that the method may be considerably less efficient than using the actual skip implementation, this is done to guarantee that the correct number of characters are skipped.

Parameters:

input - stream to skip

toSkip - the number of bytes to skip

Throws:

IOException - if there is a problem reading the file

IllegalArgumentException - if toSkip is negative

EOFException - if the number of bytes skipped was incorrect

Since:

2.0

See Also:

• InputStream.skip(long)

skipFully

public static void skipFully(InputStream input,
 long toSkip,
 Supplier<byte[]> skipBufferSupplier)
                      throws IOException

Skips the requested number of bytes or fail if there are not enough left.

Intended for special cases when customization of the temporary buffer is needed because, for example, a nested input stream has requirements for the bytes read. For example, when using InflaterInputStreams from multiple threads.

This allows for the possibility that InputStream.skip(long) may not skip as many bytes as requested (most likely because of reaching EOF).

Note that the implementation uses skip(InputStream, long). This means that the method may be considerably less efficient than using the actual skip implementation, this is done to guarantee that the correct number of characters are skipped.

Parameters:

input - stream to skip

toSkip - the number of bytes to skip

skipBufferSupplier - Supplies the buffer to use for reading.

Throws:

IOException - if there is a problem reading the file

IllegalArgumentException - if toSkip is negative

EOFException - if the number of bytes skipped was incorrect

Since:

2.14.0

See Also:

• InputStream.skip(long)

skipFully

public static void skipFully(ReadableByteChannel input,
 long toSkip)
                      throws IOException

Skips the requested number of bytes or fail if there are not enough left.

Parameters:

input - ReadableByteChannel to skip

toSkip - the number of bytes to skip

Throws:

IOException - if there is a problem reading the ReadableByteChannel

IllegalArgumentException - if toSkip is negative

EOFException - if the number of bytes skipped was incorrect

Since:

2.5

skipFully

public static void skipFully(Reader reader,
 long toSkip)
                      throws IOException

Skips the requested number of characters or fail if there are not enough left.

This allows for the possibility that Reader.skip(long) may not skip as many characters as requested (most likely because of reaching EOF).

Note that the implementation uses skip(Reader, long). This means that the method may be considerably less efficient than using the actual skip implementation, this is done to guarantee that the correct number of characters are skipped.

Parameters:

reader - stream to skip

toSkip - the number of characters to skip

Throws:

IOException - if there is a problem reading the file

IllegalArgumentException - if toSkip is negative

EOFException - if the number of characters skipped was incorrect

Since:

2.0

See Also:

• Reader.skip(long)

toBufferedInputStream

public static InputStream toBufferedInputStream(InputStream input)
                                         throws IOException

Fetches entire contents of an InputStream and represent same data as result InputStream.

This method is useful where,

• Source InputStream is slow.
• It has network resources associated, so we cannot keep it open for long time.
• It has network timeout associated.

It can be used in favor of toByteArray(InputStream), since it avoids unnecessary allocation and copy of byte[].
This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - Stream to be fully buffered.

Returns:

A fully buffered stream.

Throws:

IOException - if an I/O error occurs.

Since:

2.0

toBufferedInputStream

public static InputStream toBufferedInputStream(InputStream input,
 int size)
                                         throws IOException

Fetches entire contents of an InputStream and represent same data as result InputStream.

This method is useful where,

• Source InputStream is slow.
• It has network resources associated, so we cannot keep it open for long time.
• It has network timeout associated.

It can be used in favor of toByteArray(InputStream), since it avoids unnecessary allocation and copy of byte[].
This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - Stream to be fully buffered.

size - the initial buffer size

Returns:

A fully buffered stream.

Throws:

IOException - if an I/O error occurs.

Since:

2.5

toBufferedReader

public static BufferedReader toBufferedReader(Reader reader)

Returns the given reader if it is a BufferedReader, otherwise creates a BufferedReader from the given reader.

Parameters:

reader - the reader to wrap or return (not null)

Returns:

the given reader or a new BufferedReader for the given reader

Throws:

NullPointerException - if the input parameter is null

Since:

2.2

See Also:

• buffer(Reader)

toBufferedReader

public static BufferedReader toBufferedReader(Reader reader,
 int size)

Returns the given reader if it is a BufferedReader, otherwise creates a BufferedReader from the given reader.

Parameters:

reader - the reader to wrap or return (not null)

size - the buffer size, if a new BufferedReader is created.

Returns:

the given reader or a new BufferedReader for the given reader

Throws:

NullPointerException - if the input parameter is null

Since:

2.5

See Also:

• buffer(Reader)

toByteArray

public static byte[] toByteArray(InputStream inputStream)
                          throws IOException

Gets the contents of an InputStream as a byte[].

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

inputStream - the InputStream to read.

Returns:

the requested byte array.

Throws:

NullPointerException - if the InputStream is null.

IOException - if an I/O error occurs or reading more than Integer.MAX_VALUE occurs.

toByteArray

public static byte[] toByteArray(InputStream input,
 int size)
                          throws IOException

Gets the contents of an InputStream as a byte[]. Use this method instead of toByteArray(InputStream) when InputStream size is known.

Parameters:

input - the InputStream to read.

size - the size of InputStream to read, where 0 < size <= length of input stream.

Returns:

byte [] of length size.

Throws:

IOException - if an I/O error occurs or InputStream length is smaller than parameter size.

IllegalArgumentException - if size is less than zero.

Since:

2.1

toByteArray

public static byte[] toByteArray(InputStream input,
 long size)
                          throws IOException

Gets contents of an InputStream as a byte[]. Use this method instead of toByteArray(InputStream) when InputStream size is known. NOTE: the method checks that the length can safely be cast to an int without truncation before using toByteArray(InputStream, int) to read into the byte array. (Arrays can have no more than Integer.MAX_VALUE entries anyway)

Parameters:

input - the InputStream to read

size - the size of InputStream to read, where 0 < size <= min(Integer.MAX_VALUE, length of input stream).

Returns:

byte [] the requested byte array, of length size

Throws:

IOException - if an I/O error occurs or InputStream length is less than size

IllegalArgumentException - if size is less than zero or size is greater than Integer.MAX_VALUE

Since:

2.1

See Also:

• toByteArray(InputStream, int)

toByteArray

@Deprecated
public static byte[] toByteArray(Reader reader)
                          throws IOException

Deprecated.

Use toByteArray(Reader, Charset) instead

Gets the contents of a Reader as a byte[] using the virtual machine's default charset.

This method buffers the input internally, so there is no need to use a BufferedReader.

Parameters:

reader - the Reader to read

Returns:

the requested byte array

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

toByteArray

public static byte[] toByteArray(Reader reader,
 Charset charset)
                          throws IOException

Gets the contents of a Reader as a byte[] using the specified character encoding.

This method buffers the input internally, so there is no need to use a BufferedReader.

Parameters:

reader - the Reader to read

charset - the charset to use, null means platform default

Returns:

the requested byte array

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

Since:

2.3

toByteArray

public static byte[] toByteArray(Reader reader,
 String charsetName)
                          throws IOException

Gets the contents of a Reader as a byte[] using the specified character encoding.

Character encoding names can be found at IANA.

This method buffers the input internally, so there is no need to use a BufferedReader.

Parameters:

reader - the Reader to read

charsetName - the name of the requested charset, null means platform default

Returns:

the requested byte array

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

UnsupportedCharsetException - if the encoding is not supported

Since:

1.1

toByteArray

@Deprecated
public static byte[] toByteArray(String input)

Deprecated.

Use String.getBytes() instead

Gets the contents of a String as a byte[] using the virtual machine's default charset.

This is the same as String.getBytes().

Parameters:

input - the String to convert

Returns:

the requested byte array

Throws:

NullPointerException - if the input is null

toByteArray

public static byte[] toByteArray(URI uri)
                          throws IOException

Gets the contents of a URI as a byte[].

Parameters:

uri - the URI to read

Returns:

the requested byte array

Throws:

NullPointerException - if the uri is null

IOException - if an I/O exception occurs

Since:

2.4

toByteArray

public static byte[] toByteArray(URL url)
                          throws IOException

Gets the contents of a URL as a byte[].

Parameters:

url - the URL to read

Returns:

the requested byte array

Throws:

NullPointerException - if the input is null

IOException - if an I/O exception occurs

Since:

2.4

toByteArray

public static byte[] toByteArray(URLConnection urlConnection)
                          throws IOException

Gets the contents of a URLConnection as a byte[].

Parameters:

urlConnection - the URLConnection to read.

Returns:

the requested byte array.

Throws:

NullPointerException - if the urlConn is null.

IOException - if an I/O exception occurs.

Since:

2.4

toCharArray

@Deprecated
public static char[] toCharArray(InputStream inputStream)
                          throws IOException

Deprecated.

Use toCharArray(InputStream, Charset) instead

Gets the contents of an InputStream as a character array using the virtual machine's default charset.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

inputStream - the InputStream to read

Returns:

the requested character array

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

Since:

1.1

toCharArray

public static char[] toCharArray(InputStream inputStream,
 Charset charset)
                          throws IOException

Gets the contents of an InputStream as a character array using the specified character encoding.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

inputStream - the InputStream to read

charset - the charset to use, null means platform default

Returns:

the requested character array

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

Since:

2.3

toCharArray

public static char[] toCharArray(InputStream inputStream,
 String charsetName)
                          throws IOException

Gets the contents of an InputStream as a character array using the specified character encoding.

Character encoding names can be found at IANA.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

inputStream - the InputStream to read

charsetName - the name of the requested charset, null means platform default

Returns:

the requested character array

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

UnsupportedCharsetException - if the encoding is not supported

Since:

1.1

toCharArray

public static char[] toCharArray(Reader reader)
                          throws IOException

Gets the contents of a Reader as a character array.

This method buffers the input internally, so there is no need to use a BufferedReader.

Parameters:

reader - the Reader to read

Returns:

the requested character array

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

Since:

1.1

toInputStream

@Deprecated
public static InputStream toInputStream(CharSequence input)

Deprecated.

Use toInputStream(CharSequence, Charset) instead

Converts the specified CharSequence to an input stream, encoded as bytes using the virtual machine's default charset.

Parameters:

input - the CharSequence to convert

Returns:

an input stream

Since:

2.0

toInputStream

public static InputStream toInputStream(CharSequence input,
 Charset charset)

Converts the specified CharSequence to an input stream, encoded as bytes using the specified character encoding.

Parameters:

input - the CharSequence to convert

charset - the charset to use, null means platform default

Returns:

an input stream

Since:

2.3

toInputStream

public static InputStream toInputStream(CharSequence input,
 String charsetName)

Converts the specified CharSequence to an input stream, encoded as bytes using the specified character encoding.

Character encoding names can be found at IANA.

Parameters:

input - the CharSequence to convert

charsetName - the name of the requested charset, null means platform default

Returns:

an input stream

Throws:

UnsupportedCharsetException - if the encoding is not supported

Since:

2.0

toInputStream

@Deprecated
public static InputStream toInputStream(String input)

Deprecated.

Use toInputStream(String, Charset) instead

Converts the specified string to an input stream, encoded as bytes using the virtual machine's default charset.

Parameters:

input - the string to convert

Returns:

an input stream

Since:

1.1

toInputStream

public static InputStream toInputStream(String input,
 Charset charset)

Converts the specified string to an input stream, encoded as bytes using the specified character encoding.

Parameters:

input - the string to convert

charset - the charset to use, null means platform default

Returns:

an input stream

Since:

2.3

toInputStream

public static InputStream toInputStream(String input,
 String charsetName)

Converts the specified string to an input stream, encoded as bytes using the specified character encoding.

Character encoding names can be found at IANA.

Parameters:

input - the string to convert

charsetName - the name of the requested charset, null means platform default

Returns:

an input stream

Throws:

UnsupportedCharsetException - if the encoding is not supported

Since:

1.1

toString

@Deprecated
public static String toString(byte[] input)

Deprecated.

Use String(byte[]) instead

Gets the contents of a byte[] as a String using the virtual machine's default charset.

Parameters:

input - the byte array to read

Returns:

the requested String

Throws:

NullPointerException - if the input is null

toString

public static String toString(byte[] input,
 String charsetName)

Gets the contents of a byte[] as a String using the specified character encoding.

Character encoding names can be found at IANA.

Parameters:

input - the byte array to read

charsetName - the name of the requested charset, null means platform default

Returns:

the requested String

Throws:

NullPointerException - if the input is null

toString

@Deprecated
public static String toString(InputStream input)
                       throws IOException

Deprecated.

Use toString(InputStream, Charset) instead

Gets the contents of an InputStream as a String using the virtual machine's default charset.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - the InputStream to read

Returns:

the requested String

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

toString

public static String toString(InputStream input,
 Charset charset)
                       throws IOException

Gets the contents of an InputStream as a String using the specified character encoding.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - the InputStream to read

charset - the charset to use, null means platform default

Returns:

the requested String

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

Since:

2.3

toString

public static String toString(InputStream input,
 String charsetName)
                       throws IOException

Gets the contents of an InputStream as a String using the specified character encoding.

Character encoding names can be found at IANA.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - the InputStream to read

charsetName - the name of the requested charset, null means platform default

Returns:

the requested String

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

UnsupportedCharsetException - if the encoding is not supported

toString

public static String toString(IOSupplier<InputStream> input,
 Charset charset)
                       throws IOException

Gets the contents of an InputStream from a supplier as a String using the specified character encoding.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - supplies the InputStream to read

charset - the charset to use, null means platform default

Returns:

the requested String

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

Since:

2.12.0

toString

public static String toString(IOSupplier<InputStream> input,
 Charset charset,
 IOSupplier<String> defaultString)
                       throws IOException

Gets the contents of an InputStream from a supplier as a String using the specified character encoding.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - supplies the InputStream to read

charset - the charset to use, null means platform default

defaultString - the default return value if the supplier or its value is null.

Returns:

the requested String

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

Since:

2.12.0

toString

public static String toString(Reader reader)
                       throws IOException

Gets the contents of a Reader as a String.

This method buffers the input internally, so there is no need to use a BufferedReader.

Parameters:

reader - the Reader to read

Returns:

the requested String

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

toString

@Deprecated
public static String toString(URI uri)
                       throws IOException

Deprecated.

Use toString(URI, Charset) instead

Gets the contents at the given URI using the virtual machine's default charset.

Parameters:

uri - The URI source.

Returns:

The contents of the URL as a String.

Throws:

IOException - if an I/O exception occurs.

Since:

2.1

toString

public static String toString(URI uri,
 Charset encoding)
                       throws IOException

Gets the contents at the given URI.

Parameters:

uri - The URI source.

encoding - The encoding name for the URL contents.

Returns:

The contents of the URL as a String.

Throws:

IOException - if an I/O exception occurs.

Since:

2.3.

toString

public static String toString(URI uri,
 String charsetName)
                       throws IOException

Gets the contents at the given URI.

Parameters:

uri - The URI source.

charsetName - The encoding name for the URL contents.

Returns:

The contents of the URL as a String.

Throws:

IOException - if an I/O exception occurs.

UnsupportedCharsetException - if the encoding is not supported

Since:

2.1

toString

@Deprecated
public static String toString(URL url)
                       throws IOException

Deprecated.

Use toString(URL, Charset) instead

Gets the contents at the given URL using the virtual machine's default charset.

Parameters:

url - The URL source.

Returns:

The contents of the URL as a String.

Throws:

IOException - if an I/O exception occurs.

Since:

2.1

toString

public static String toString(URL url,
 Charset encoding)
                       throws IOException

Gets the contents at the given URL.

Parameters:

url - The URL source.

encoding - The encoding name for the URL contents.

Returns:

The contents of the URL as a String.

Throws:

IOException - if an I/O exception occurs.

Since:

2.3

toString

public static String toString(URL url,
 String charsetName)
                       throws IOException

Gets the contents at the given URL.

Parameters:

url - The URL source.

charsetName - The encoding name for the URL contents.

Returns:

The contents of the URL as a String.

Throws:

IOException - if an I/O exception occurs.

UnsupportedCharsetException - if the encoding is not supported

Since:

2.1

write

public static void write(byte[] data,
 OutputStream output)
                  throws IOException

Writes bytes from a byte[] to an OutputStream.

Parameters:

data - the byte array to write, do not modify during output, null ignored

output - the OutputStream to write to

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

1.1

write

@Deprecated
public static void write(byte[] data,
 Writer writer)
                  throws IOException

Deprecated.

Use write(byte[], Writer, Charset) instead

Writes bytes from a byte[] to chars on a Writer using the virtual machine's default charset.

This method uses String(byte[]).

Parameters:

data - the byte array to write, do not modify during output, null ignored

writer - the Writer to write to

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

1.1

write

public static void write(byte[] data,
 Writer writer,
 Charset charset)
                  throws IOException

Writes bytes from a byte[] to chars on a Writer using the specified character encoding.

This method uses String(byte[], String).

Parameters:

data - the byte array to write, do not modify during output, null ignored

writer - the Writer to write to

charset - the charset to use, null means platform default

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

2.3

write

public static void write(byte[] data,
 Writer writer,
 String charsetName)
                  throws IOException

Writes bytes from a byte[] to chars on a Writer using the specified character encoding.

Character encoding names can be found at IANA.

This method uses String(byte[], String).

Parameters:

data - the byte array to write, do not modify during output, null ignored

writer - the Writer to write to

charsetName - the name of the requested charset, null means platform default

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

UnsupportedCharsetException - if the encoding is not supported

Since:

1.1

write

@Deprecated
public static void write(char[] data,
 OutputStream output)
                  throws IOException

Deprecated.

Use write(char[], OutputStream, Charset) instead

Writes chars from a char[] to bytes on an OutputStream.

This method uses the virtual machine's default charset.

Parameters:

data - the char array to write, do not modify during output, null ignored

output - the OutputStream to write to

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

1.1

write

public static void write(char[] data,
 OutputStream output,
 Charset charset)
                  throws IOException

Writes chars from a char[] to bytes on an OutputStream using the specified character encoding.

This method uses String(char[]) and String.getBytes(String).

Parameters:

data - the char array to write, do not modify during output, null ignored

output - the OutputStream to write to

charset - the charset to use, null means platform default

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

2.3

write

public static void write(char[] data,
 OutputStream output,
 String charsetName)
                  throws IOException

Writes chars from a char[] to bytes on an OutputStream using the specified character encoding.

Character encoding names can be found at IANA.

This method uses String(char[]) and String.getBytes(String).

Parameters:

data - the char array to write, do not modify during output, null ignored

output - the OutputStream to write to

charsetName - the name of the requested charset, null means platform default

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

UnsupportedCharsetException - if the encoding is not supported

Since:

1.1

write

public static void write(char[] data,
 Writer writer)
                  throws IOException

Writes chars from a char[] to a Writer

Parameters:

data - the char array to write, do not modify during output, null ignored

writer - the Writer to write to

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

1.1

write

@Deprecated
public static void write(CharSequence data,
 OutputStream output)
                  throws IOException

Deprecated.

Use write(CharSequence, OutputStream, Charset) instead

Writes chars from a CharSequence to bytes on an OutputStream using the virtual machine's default charset.

This method uses String.getBytes().

Parameters:

data - the CharSequence to write, null ignored

output - the OutputStream to write to

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

2.0

write

public static void write(CharSequence data,
 OutputStream output,
 Charset charset)
                  throws IOException

Writes chars from a CharSequence to bytes on an OutputStream using the specified character encoding.

This method uses String.getBytes(String).

Parameters:

data - the CharSequence to write, null ignored

output - the OutputStream to write to

charset - the charset to use, null means platform default

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

2.3

write

public static void write(CharSequence data,
 OutputStream output,
 String charsetName)
                  throws IOException

Writes chars from a CharSequence to bytes on an OutputStream using the specified character encoding.

Character encoding names can be found at IANA.

This method uses String.getBytes(String).

Parameters:

data - the CharSequence to write, null ignored

output - the OutputStream to write to

charsetName - the name of the requested charset, null means platform default

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

UnsupportedCharsetException - if the encoding is not supported

Since:

2.0

write

public static void write(CharSequence data,
 Writer writer)
                  throws IOException

Writes chars from a CharSequence to a Writer.

Parameters:

data - the CharSequence to write, null ignored

writer - the Writer to write to

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

2.0

write

@Deprecated
public static void write(String data,
 OutputStream output)
                  throws IOException

Deprecated.

Use write(String, OutputStream, Charset) instead

Writes chars from a String to bytes on an OutputStream using the virtual machine's default charset.

This method uses String.getBytes().

Parameters:

data - the String to write, null ignored

output - the OutputStream to write to

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

1.1

write

public static void write(String data,
 OutputStream output,
 Charset charset)
                  throws IOException

Writes chars from a String to bytes on an OutputStream using the specified character encoding.

This method uses String.getBytes(String).

Parameters:

data - the String to write, null ignored

output - the OutputStream to write to

charset - the charset to use, null means platform default

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

2.3

write

public static void write(String data,
 OutputStream output,
 String charsetName)
                  throws IOException

Writes chars from a String to bytes on an OutputStream using the specified character encoding.

Character encoding names can be found at IANA.

This method uses String.getBytes(String).

Parameters:

data - the String to write, null ignored

output - the OutputStream to write to

charsetName - the name of the requested charset, null means platform default

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

UnsupportedCharsetException - if the encoding is not supported

Since:

1.1

write

public static void write(String data,
 Writer writer)
                  throws IOException

Writes chars from a String to a Writer.

Parameters:

data - the String to write, null ignored

writer - the Writer to write to

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

1.1

write

@Deprecated
public static void write(StringBuffer data,
 OutputStream output)
                  throws IOException

Deprecated.

Use write(CharSequence, OutputStream)

Writes chars from a StringBuffer to bytes on an OutputStream using the default character encoding of the platform.

This method uses String.getBytes().

Parameters:

data - the StringBuffer to write, null ignored

output - the OutputStream to write to

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

1.1

write

@Deprecated
public static void write(StringBuffer data,
 OutputStream output,
 String charsetName)
                  throws IOException

Deprecated.

Use write(CharSequence, OutputStream, String).

Writes chars from a StringBuffer to bytes on an OutputStream using the specified character encoding.

Character encoding names can be found at IANA.

This method uses String.getBytes(String).

Parameters:

data - the StringBuffer to write, null ignored

output - the OutputStream to write to

charsetName - the name of the requested charset, null means platform default

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

UnsupportedCharsetException - if the encoding is not supported

Since:

1.1

write

@Deprecated
public static void write(StringBuffer data,
 Writer writer)
                  throws IOException

Deprecated.

Use write(CharSequence, Writer)

Writes chars from a StringBuffer to a Writer.

Parameters:

data - the StringBuffer to write, null ignored

writer - the Writer to write to

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

1.1

writeChunked

public static void writeChunked(byte[] data,
 OutputStream output)
                         throws IOException

Writes bytes from a byte[] to an OutputStream using chunked writes. This is intended for writing very large byte arrays which might otherwise cause excessive memory usage if the native code has to allocate a copy.

Parameters:

data - the byte array to write, do not modify during output, null ignored

output - the OutputStream to write to

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

2.5

writeChunked

public static void writeChunked(char[] data,
 Writer writer)
                         throws IOException

Writes chars from a char[] to a Writer using chunked writes. This is intended for writing very large byte arrays which might otherwise cause excessive memory usage if the native code has to allocate a copy.

Parameters:

data - the char array to write, do not modify during output, null ignored

writer - the Writer to write to

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

2.5

writeLines

@Deprecated
public static void writeLines(Collection<?> lines,
 String lineEnding,
 OutputStream output)
                       throws IOException

Deprecated.

Use writeLines(Collection, String, OutputStream, Charset) instead

Writes the Object.toString() value of each item in a collection to an OutputStream line by line, using the virtual machine's default charset and the specified line ending.

Parameters:

lines - the lines to write, null entries produce blank lines

lineEnding - the line separator to use, null is system default

output - the OutputStream to write to, not null, not closed

Throws:

NullPointerException - if the output is null

IOException - if an I/O error occurs

Since:

1.1

writeLines

public static void writeLines(Collection<?> lines,
 String lineEnding,
 OutputStream output,
 Charset charset)
                       throws IOException

Writes the Object.toString() value of each item in a collection to an OutputStream line by line, using the specified character encoding and the specified line ending.

UTF-16 is written big-endian with no byte order mark. For little-endian, use UTF-16LE. For a BOM, write it to the stream before calling this method.

Parameters:

lines - the lines to write, null entries produce blank lines

lineEnding - the line separator to use, null is system default

output - the OutputStream to write to, not null, not closed

charset - the charset to use, null means platform default

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

2.3

writeLines

public static void writeLines(Collection<?> lines,
 String lineEnding,
 OutputStream output,
 String charsetName)
                       throws IOException

Writes the Object.toString() value of each item in a collection to an OutputStream line by line, using the specified character encoding and the specified line ending.

Character encoding names can be found at IANA.

Parameters:

lines - the lines to write, null entries produce blank lines

lineEnding - the line separator to use, null is system default

output - the OutputStream to write to, not null, not closed

charsetName - the name of the requested charset, null means platform default

Throws:

NullPointerException - if the output is null

IOException - if an I/O error occurs

UnsupportedCharsetException - if the encoding is not supported

Since:

1.1

writeLines

public static void writeLines(Collection<?> lines,
 String lineEnding,
 Writer writer)
                       throws IOException

Writes the Object.toString() value of each item in a collection to a Writer line by line, using the specified line ending.

Parameters:

lines - the lines to write, null entries produce blank lines

lineEnding - the line separator to use, null is system default

writer - the Writer to write to, not null, not closed

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

Since:

1.1

writer

public static Writer writer(Appendable appendable)

Returns the given Appendable if it is already a Writer, otherwise creates a Writer wrapper around the given Appendable.

Parameters:

appendable - the Appendable to wrap or return (not null)

Returns:

the given Appendable or a Writer wrapper around the given Appendable

Throws:

NullPointerException - if the input parameter is null

Since:

2.7