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.

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.

Origin of code: Excalibur.

Version:

$Id: IOUtils.java 481854 2006-12-03 18:30:07Z scolebourne $

Author:

Peter Donald, Jeff Turner, Matthew Hawthorne, Stephen Colebourne, Gareth Davis, Ian Springer, Niall Pemberton, Sandy McArthur

Field Summary

static char	DIR_SEPARATOR The system directory separator character.
static char	DIR_SEPARATOR_UNIX The Unix directory separator character.
static char	DIR_SEPARATOR_WINDOWS The Windows directory separator character.
static String	LINE_SEPARATOR The system line separator string.
static String	LINE_SEPARATOR_UNIX The Unix line separator string.
static String	LINE_SEPARATOR_WINDOWS The Windows line separator string.

Constructor Summary

IOUtils()
Instances should NOT be constructed in standard programming.

Method Summary

static void	closeQuietly(InputStream input) Unconditionally close an InputStream.
static void	closeQuietly(OutputStream output) Unconditionally close an OutputStream.
static void	closeQuietly(Reader input) Unconditionally close an Reader.
static void	closeQuietly(Writer output) Unconditionally close a Writer.
static boolean	contentEquals(InputStream input1, InputStream input2) Compare the contents of two Streams to determine if they are equal or not.
static boolean	contentEquals(Reader input1, Reader input2) Compare the contents of two Readers to determine if they are equal or not.
static int	copy(InputStream input, OutputStream output) Copy bytes from an InputStream to an OutputStream.
static void	copy(InputStream input, Writer output) Copy bytes from an InputStream to chars on a Writer using the default character encoding of the platform.
static void	copy(InputStream input, Writer output, String encoding) Copy bytes from an InputStream to chars on a Writer using the specified character encoding.
static void	copy(Reader input, OutputStream output) Copy chars from a Reader to bytes on an OutputStream using the default character encoding of the platform, and calling flush.
static void	copy(Reader input, OutputStream output, String encoding) Copy chars from a Reader to bytes on an OutputStream using the specified character encoding, and calling flush.
static int	copy(Reader input, Writer output) Copy chars from a Reader to a Writer.
static long	copyLarge(InputStream input, OutputStream output) Copy bytes from a large (over 2GB) InputStream to an OutputStream.
static long	copyLarge(Reader input, Writer output) Copy chars from a large (over 2GB) Reader to a Writer.
static LineIterator	lineIterator(InputStream input, String encoding) Return an Iterator for the lines in an InputStream, using the character encoding specified (or default encoding if null).
static LineIterator	lineIterator(Reader reader) Return an Iterator for the lines in a Reader.
static List	readLines(InputStream input) Get the contents of an InputStream as a list of Strings, one entry per line, using the default character encoding of the platform.
static List	readLines(InputStream input, String encoding) Get the contents of an InputStream as a list of Strings, one entry per line, using the specified character encoding.
static List	readLines(Reader input) Get the contents of a Reader as a list of Strings, one entry per line.
static byte[]	toByteArray(InputStream input) Get the contents of an InputStream as a byte[].
static byte[]	toByteArray(Reader input) Get the contents of a Reader as a byte[] using the default character encoding of the platform.
static byte[]	toByteArray(Reader input, String encoding) Get the contents of a Reader as a byte[] using the specified character encoding.
static byte[]	toByteArray(String input) Deprecated. Use String.getBytes()
static char[]	toCharArray(InputStream is) Get the contents of an InputStream as a character array using the default character encoding of the platform.
static char[]	toCharArray(InputStream is, String encoding) Get the contents of an InputStream as a character array using the specified character encoding.
static char[]	toCharArray(Reader input) Get the contents of a Reader as a character array.
static InputStream	toInputStream(String input) Convert the specified string to an input stream, encoded as bytes using the default character encoding of the platform.
static InputStream	toInputStream(String input, String encoding) Convert the specified string to an input stream, encoded as bytes using the specified character encoding.
static String	toString(byte[] input) Deprecated. Use String.String(byte[])
static String	toString(byte[] input, String encoding) Deprecated. Use String.String(byte[],String)
static String	toString(InputStream input) Get the contents of an InputStream as a String using the default character encoding of the platform.
static String	toString(InputStream input, String encoding) Get the contents of an InputStream as a String using the specified character encoding.
static String	toString(Reader input) Get the contents of a Reader as a String.
static void	write(byte[] data, OutputStream output) Writes bytes from a byte[] to an OutputStream.
static void	write(byte[] data, Writer output) Writes bytes from a byte[] to chars on a Writer using the default character encoding of the platform.
static void	write(byte[] data, Writer output, String encoding) Writes bytes from a byte[] to chars on a Writer using the specified character encoding.
static void	write(char[] data, OutputStream output) Writes chars from a char[] to bytes on an OutputStream.
static void	write(char[] data, OutputStream output, String encoding) Writes chars from a char[] to bytes on an OutputStream using the specified character encoding.
static void	write(char[] data, Writer output) Writes chars from a char[] to a Writer using the default character encoding of the platform.
static void	write(StringBuffer data, OutputStream output) Writes chars from a StringBuffer to bytes on an OutputStream using the default character encoding of the platform.
static void	write(StringBuffer data, OutputStream output, String encoding) Writes chars from a StringBuffer to bytes on an OutputStream using the specified character encoding.
static void	write(StringBuffer data, Writer output) Writes chars from a StringBuffer to a Writer.
static void	write(String data, OutputStream output) Writes chars from a String to bytes on an OutputStream using the default character encoding of the platform.
static void	write(String data, OutputStream output, String encoding) Writes chars from a String to bytes on an OutputStream using the specified character encoding.
static void	write(String data, Writer output) Writes chars from a String to a Writer.
static void	writeLines(Collection lines, String lineEnding, OutputStream output) Writes the toString() value of each item in a collection to an OutputStream line by line, using the default character encoding of the platform and the specified line ending.
static void	writeLines(Collection lines, String lineEnding, OutputStream output, String encoding) Writes the 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 toString() value of each item in a collection to a Writer line by line, using the specified line ending.

Methods inherited from class java.lang.Object

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

Field Detail

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

DIR_SEPARATOR

public static final char DIR_SEPARATOR

The system directory separator character.

LINE_SEPARATOR_UNIX

public static final String LINE_SEPARATOR_UNIX

The Unix line separator string.

See Also:

Constant Field Values

LINE_SEPARATOR_WINDOWS

public static final String LINE_SEPARATOR_WINDOWS

The Windows line separator string.

See Also:

Constant Field Values

LINE_SEPARATOR

public static final String LINE_SEPARATOR

The system line separator string.

Constructor Detail

IOUtils

public IOUtils()

Instances should NOT be constructed in standard programming.

Method Detail

closeQuietly

public static void closeQuietly(Reader input)

Unconditionally close an Reader.

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

Parameters:

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

closeQuietly

public static void closeQuietly(Writer output)

Unconditionally close a Writer.

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

Parameters:

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

closeQuietly

public static void closeQuietly(InputStream input)

Unconditionally close an InputStream.

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

Parameters:

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

closeQuietly

public static void closeQuietly(OutputStream output)

Unconditionally close an OutputStream.

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

Parameters:

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

toByteArray

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

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

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

Parameters:

input - the InputStream to read from

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 input)
                          throws IOException

Get the contents of a Reader as a byte[] using the default character encoding of the platform.

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

Parameters:

input - the Reader to read from

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 input,
                                 String encoding)
                          throws IOException

Get 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:

input - the Reader to read from

encoding - the encoding 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:

Commons IO 1.1

toByteArray

public static byte[] toByteArray(String input)
                          throws IOException

Deprecated. Use String.getBytes()

Get the contents of a String as a byte[] using the default character encoding of the platform.

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

IOException - if an I/O error occurs (never occurs)

toCharArray

public static char[] toCharArray(InputStream is)
                          throws IOException

Get the contents of an InputStream as a character array using the default character encoding of the platform.

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

Parameters:

is - the InputStream to read from

Returns:

the requested character array

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

toCharArray

public static char[] toCharArray(InputStream is,
                                 String encoding)
                          throws IOException

Get 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:

is - the InputStream to read from

encoding - the encoding 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:

Commons IO 1.1

toCharArray

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

Get 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:

input - the Reader to read from

Returns:

the requested character array

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

toString

public static String toString(InputStream input)
                       throws IOException

Get the contents of an InputStream as a String using the default character encoding of the platform.

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

Parameters:

input - the InputStream to read from

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,
                              String encoding)
                       throws IOException

Get 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 from

encoding - the encoding to use, null means platform default

Returns:

the requested String

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

toString

public static String toString(Reader input)
                       throws IOException

Get the contents of a Reader as a String.

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

Parameters:

input - the Reader to read from

Returns:

the requested String

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

toString

public static String toString(byte[] input)
                       throws IOException

Deprecated. Use String.String(byte[])

Get the contents of a byte[] as a String using the default character encoding of the platform.

Parameters:

input - the byte array to read from

Returns:

the requested String

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs (never occurs)

toString

public static String toString(byte[] input,
                              String encoding)
                       throws IOException

Deprecated. Use String.String(byte[],String)

Get 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 from

encoding - the encoding to use, null means platform default

Returns:

the requested String

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs (never occurs)

readLines

public static List readLines(InputStream input)
                      throws IOException

Get the contents of an InputStream as a list of Strings, one entry per line, using the default character encoding of the platform.

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

Parameters:

input - the InputStream to read from, not null

Returns:

the list of Strings, never null

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

readLines

public static List readLines(InputStream input,
                             String encoding)
                      throws IOException

Get 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 from, not null

encoding - the encoding to use, null means platform default

Returns:

the list of Strings, never null

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

readLines

public static List readLines(Reader input)
                      throws IOException

Get 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:

input - the Reader to read from, not null

Returns:

the list of Strings, never null

Throws:

NullPointerException - if the input is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

lineIterator

public static LineIterator lineIterator(Reader reader)

Return 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 closing the reader directly, or by calling LineIterator.close() or LineIterator.closeQuietly(LineIterator).

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 from, not null

Returns:

an Iterator of the lines in the reader, never null

Throws:

IllegalArgumentException - if the reader is null

Since:

Commons IO 1.2

lineIterator

public static LineIterator lineIterator(InputStream input,
                                        String encoding)
                                 throws IOException

Return 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 closing the stream directly, or by calling LineIterator.close() or LineIterator.closeQuietly(LineIterator).

The recommended usage pattern is:

 try {
   LineIterator it = IOUtils.lineIterator(stream, "UTF-8");
   while (it.hasNext()) {
     String line = it.nextLine();
     /// do something with line
   }
 } finally {
   IOUtils.closeQuietly(stream);
 }
 

Parameters:

input - the InputStream to read from, not null

encoding - 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

IOException - if an I/O error occurs, such as if the encoding is invalid

Since:

Commons IO 1.2

toInputStream

public static InputStream toInputStream(String input)

Convert the specified string to an input stream, encoded as bytes using the default character encoding of the platform.

Parameters:

input - the string to convert

Returns:

an input stream

Since:

Commons IO 1.1

toInputStream

public static InputStream toInputStream(String input,
                                        String encoding)
                                 throws IOException

Convert 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

encoding - the encoding to use, null means platform default

Returns:

an input stream

Throws:

IOException - if the encoding is invalid

Since:

Commons IO 1.1

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:

Commons IO 1.1

write

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

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

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

Parameters:

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

output - the Writer to write to

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

public static void write(byte[] data,
                         Writer output,
                         String encoding)
                  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.String(byte[], String).

Parameters:

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

output - the Writer to write to

encoding - the encoding to use, null means platform default

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

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

Writes chars from a char[] to a Writer using the default character encoding of the platform.

Parameters:

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

output - the Writer to write to

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

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

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

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

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:

Commons IO 1.1

write

public static void write(char[] data,
                         OutputStream output,
                         String encoding)
                  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.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

encoding - the encoding to use, null means platform default

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

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

Writes chars from a String to a Writer.

Parameters:

data - the String to write, null ignored

output - the Writer to write to

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

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

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

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:

Commons IO 1.1

write

public static void write(String data,
                         OutputStream output,
                         String encoding)
                  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

encoding - the encoding to use, null means platform default

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

public static void write(StringBuffer data,
                         Writer output)
                  throws IOException

Writes chars from a StringBuffer to a Writer.

Parameters:

data - the StringBuffer to write, null ignored

output - the Writer to write to

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

write

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

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:

Commons IO 1.1

write

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

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

encoding - the encoding to use, null means platform default

Throws:

NullPointerException - if output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

writeLines

public static void writeLines(Collection lines,
                              String lineEnding,
                              OutputStream output)
                       throws IOException

Writes the toString() value of each item in a collection to an OutputStream line by line, using the default character encoding of the platform 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:

Commons IO 1.1

writeLines

public static void writeLines(Collection lines,
                              String lineEnding,
                              OutputStream output,
                              String encoding)
                       throws IOException

Writes the 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

encoding - the encoding to use, null means platform default

Throws:

NullPointerException - if the output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

writeLines

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

Writes the 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:

Commons IO 1.1

copy

public static int copy(InputStream input,
                       OutputStream output)
                throws IOException

Copy 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:

input - the InputStream to read from

output - the OutputStream to write to

Returns:

the number of bytes copied

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

ArithmeticException - if the byte count is too large

Since:

Commons IO 1.1

copyLarge

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

Copy 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.

Parameters:

input - the InputStream to read from

output - the OutputStream to write to

Returns:

the number of bytes copied

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.3

copy

public static void copy(InputStream input,
                        Writer output)
                 throws IOException

Copy bytes from an InputStream to chars on a Writer using the default character encoding of the platform.

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 from

output - the Writer to write to

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

copy

public static void copy(InputStream input,
                        Writer output,
                        String encoding)
                 throws IOException

Copy 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 from

output - the Writer to write to

encoding - the encoding to use, null means platform default

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

copy

public static int copy(Reader input,
                       Writer output)
                throws IOException

Copy 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:

input - the Reader to read from

output - the Writer to write to

Returns:

the number of characters copied

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

ArithmeticException - if the character count is too large

Since:

Commons IO 1.1

copyLarge

public static long copyLarge(Reader input,
                             Writer output)
                      throws IOException

Copy 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.

Parameters:

input - the Reader to read from

output - the Writer to write to

Returns:

the number of characters copied

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.3

copy

public static void copy(Reader input,
                        OutputStream output)
                 throws IOException

Copy chars from a Reader to bytes on an OutputStream using the default character encoding of the platform, 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:

input - the Reader to read from

output - the OutputStream to write to

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

copy

public static void copy(Reader input,
                        OutputStream output,
                        String encoding)
                 throws IOException

Copy 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:

input - the Reader to read from

output - the OutputStream to write to

encoding - the encoding to use, null means platform default

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

contentEquals

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

Compare 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:

NullPointerException - if either input is null

IOException - if an I/O error occurs

contentEquals

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

Compare 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:

Commons IO 1.1