@Deprecated public class CopyUtils extends Object
InputStream, Reader,
String and byte[]) and destinations
(OutputStream, Writer, String and
byte[]).
Unless otherwise noted, these copy methods do not
flush or close the streams. Often doing so would require making non-portable
assumptions about the streams' origin and further use. This means that both
streams' close() methods must be called after copying. if one
omits this step, then the stream resources (sockets, file descriptors) are
released when the associated Stream is garbage-collected. It is not a good
idea to rely on this mechanism. For a good overview of the distinction
between "memory management" and "resource management", see
this
UnixReview article.
For byte-to-char methods, a copy variant allows the encoding
to be selected (otherwise the platform default is used). We would like to
encourage you to always specify the encoding because relying on the platform
default can lead to unexpected results.
We don't provide special variants for the copy methods that
let you specify the buffer size because in modern VMs the impact on speed
seems to be minimal. We're using a default buffer size of 4 KB.
The copy methods use an internal buffer when copying. It is
therefore advisable not to deliberately wrap the stream arguments
to the copy methods in Buffered* streams. For
example, don't do the following:
copy( new BufferedInputStream( in ), new BufferedOutputStream( out ) );The rationale is as follows:
Imagine that an InputStream's read() is a very expensive operation, which
would usually suggest wrapping in a BufferedInputStream. The
BufferedInputStream works by issuing infrequent
InputStream.read(byte[] b, int off, int len) requests on the
underlying InputStream, to fill an internal buffer, from which further
read requests can inexpensively get their data (until the buffer
runs out).
However, the copy methods do the same thing, keeping an
internal buffer, populated by
InputStream.read(byte[] b, int off, int len) requests. Having two
buffers (or three if the destination stream is also buffered) is pointless,
and the unnecessary buffer management hurts performance slightly (about 3%,
according to some simple experiments).
Behold, intrepid explorers; a map of this class:
Method Input Output Dependency
------ ----- ------ -------
1 copy InputStream OutputStream (primitive)
2 copy Reader Writer (primitive)
3 copy InputStream Writer 2
4 copy Reader OutputStream 2
5 copy String OutputStream 2
6 copy String Writer (trivial)
7 copy byte[] Writer 3
8 copy byte[] OutputStream (trivial)
Note that only the first two methods shuffle bytes; the rest use these two, or (if possible) copy using native Java copy methods. As there are method variants to specify the encoding, each row may correspond to up to 2 methods.
Origin of code: Excalibur.
| Constructor and Description |
|---|
CopyUtils()
Deprecated.
Instances should NOT be constructed in standard programming.
|
| Modifier and Type | Method and Description |
|---|---|
static void |
copy(byte[] input,
OutputStream output)
Deprecated.
Copy bytes from a
byte[] to an OutputStream. |
static void |
copy(byte[] input,
Writer output)
Deprecated.
2.5 use
copy(byte[], Writer, String) instead |
static void |
copy(byte[] input,
Writer output,
String encoding)
Deprecated.
Copy and convert bytes from a
byte[] to chars on a
Writer, using the specified encoding. |
static int |
copy(InputStream input,
OutputStream output)
Deprecated.
Copy bytes from an
InputStream to an
OutputStream. |
static void |
copy(InputStream input,
Writer output)
Deprecated.
2.5 use
copy(InputStream, Writer, String) instead |
static void |
copy(InputStream input,
Writer output,
String encoding)
Deprecated.
Copy and convert bytes from an
InputStream to chars on a
Writer, using the specified encoding. |
static void |
copy(Reader input,
OutputStream output)
Deprecated.
2.5 use
copy(Reader, OutputStream, String) instead |
static void |
copy(Reader input,
OutputStream output,
String encoding)
Deprecated.
Serialize chars from a
Reader to bytes on an
OutputStream, and flush the OutputStream. |
static int |
copy(Reader input,
Writer output)
Deprecated.
Copy chars from a
Reader to a Writer. |
static void |
copy(String input,
OutputStream output)
Deprecated.
2.5 use
copy(String, OutputStream, String) instead |
static void |
copy(String input,
OutputStream output,
String encoding)
Deprecated.
Serialize chars from a
String to bytes on an
OutputStream, and
flush the OutputStream. |
static void |
copy(String input,
Writer output)
Deprecated.
Copy chars from a
String to a Writer. |
public CopyUtils()
public static void copy(byte[] input, OutputStream output) throws IOException
byte[] to an OutputStream.input - the byte array to read fromoutput - the OutputStream to write toIOException - In case of an I/O problem@Deprecated public static void copy(byte[] input, Writer output) throws IOException
copy(byte[], Writer, String) insteadbyte[] to chars on a
Writer.
The platform's default encoding is used for the byte-to-char conversion.input - the byte array to read fromoutput - the Writer to write toIOException - In case of an I/O problempublic static void copy(byte[] input, Writer output, String encoding) throws IOException
byte[] to chars on a
Writer, using the specified encoding.input - the byte array to read fromoutput - the Writer to write toencoding - The name of a supported character encoding. See the
IANA
Charset Registry for a list of valid encoding types.IOException - In case of an I/O problempublic static int copy(InputStream input, OutputStream output) throws IOException
InputStream to an
OutputStream.input - the InputStream to read fromoutput - the OutputStream to write toIOException - In case of an I/O problempublic static int copy(Reader input, Writer output) throws IOException
Reader to a Writer.input - the Reader to read fromoutput - the Writer to write toIOException - In case of an I/O problem@Deprecated public static void copy(InputStream input, Writer output) throws IOException
copy(InputStream, Writer, String) insteadInputStream to chars on a
Writer.
The platform's default encoding is used for the byte-to-char conversion.input - the InputStream to read fromoutput - the Writer to write toIOException - In case of an I/O problempublic static void copy(InputStream input, Writer output, String encoding) throws IOException
InputStream to chars on a
Writer, using the specified encoding.input - the InputStream to read fromoutput - the Writer to write toencoding - The name of a supported character encoding. See the
IANA
Charset Registry for a list of valid encoding types.IOException - In case of an I/O problem@Deprecated public static void copy(Reader input, OutputStream output) throws IOException
copy(Reader, OutputStream, String) insteadReader to bytes on an
OutputStream, and flush the OutputStream.
Uses the default platform encoding.input - the Reader to read fromoutput - the OutputStream to write toIOException - In case of an I/O problempublic static void copy(Reader input, OutputStream output, String encoding) throws IOException
Reader to bytes on an
OutputStream, and flush the OutputStream.input - the Reader to read fromoutput - the OutputStream to write toencoding - The name of a supported character encoding. See the
IANA
Charset Registry for a list of valid encoding types.IOException - In case of an I/O problem@Deprecated public static void copy(String input, OutputStream output) throws IOException
copy(String, OutputStream, String) insteadString to bytes on an
OutputStream, and
flush the OutputStream.
Uses the platform default encoding.input - the String to read fromoutput - the OutputStream to write toIOException - In case of an I/O problempublic static void copy(String input, OutputStream output, String encoding) throws IOException
String to bytes on an
OutputStream, and
flush the OutputStream.input - the String to read fromoutput - the OutputStream to write toencoding - The name of a supported character encoding. See the
IANA
Charset Registry for a list of valid encoding types.IOException - In case of an I/O problempublic static void copy(String input, Writer output) throws IOException
String to a Writer.input - the String to read fromoutput - the Writer to write toIOException - In case of an I/O problemCopyright © 2002–2016 The Apache Software Foundation. All rights reserved.