Java™ Platform
Standard Ed. 6

java.io
Class OutputStreamWriter

java.lang.Object
  extended by java.io.Writer
      extended by java.io.OutputStreamWriter
All Implemented Interfaces:
Closeable, Flushable, Appendable
Direct Known Subclasses:
FileWriter

public class OutputStreamWriter
extends Writer

An OutputStreamWriter is a bridge from character streams to byte streams: Characters written to it are encoded into bytes using a specified charset. The charset that it uses may be specified by name or may be given explicitly, or the platform's default charset may be accepted.

Each invocation of a write() method causes the encoding converter to be invoked on the given character(s). The resulting bytes are accumulated in a buffer before being written to the underlying output stream. The size of this buffer may be specified, but by default it is large enough for most purposes. Note that the characters passed to the write() methods are not buffered.

For top efficiency, consider wrapping an OutputStreamWriter within a BufferedWriter so as to avoid frequent converter invocations. For example:

 Writer out
   = new BufferedWriter(new OutputStreamWriter(System.out));
 

A surrogate pair is a character represented by a sequence of two char values: A high surrogate in the range '\uD800' to '\uDBFF' followed by a low surrogate in the range '\uDC00' to '\uDFFF'.

A malformed surrogate element is a high surrogate that is not followed by a low surrogate or a low surrogate that is not preceded by a high surrogate.

This class always replaces malformed surrogate elements and unmappable character sequences with the charset's default substitution sequence. The CharsetEncoder class should be used when more control over the encoding process is required.

Since:
JDK1.1
See Also:
BufferedWriter, OutputStream, Charset

Field Summary
 
Fields inherited from class java.io.Writer
lock
 
Constructor Summary
OutputStreamWriter(OutputStream out)
          Creates an OutputStreamWriter that uses the default character encoding.
OutputStreamWriter(OutputStream out, Charset cs)
          Creates an OutputStreamWriter that uses the given charset.
OutputStreamWriter(OutputStream out, CharsetEncoder enc)
          Creates an OutputStreamWriter that uses the given charset encoder.
OutputStreamWriter(OutputStream out, String charsetName)
          Creates an OutputStreamWriter that uses the named charset.
 
Method Summary
 void close()
          Closes the stream, flushing it first.
 void flush()
          Flushes the stream.
 String getEncoding()
          Returns the name of the character encoding being used by this stream.
 void write(char[] cbuf, int off, int len)
          Writes a portion of an array of characters.
 void write(int c)
          Writes a single character.
 void write(String str, int off, int len)
          Writes a portion of a string.
 
Methods inherited from class java.io.Writer
append, append, append, write, write
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

OutputStreamWriter

public OutputStreamWriter(OutputStream out,
                          String charsetName)
                   throws UnsupportedEncodingException
Creates an OutputStreamWriter that uses the named charset.

Parameters:
out - An OutputStream
charsetName - The name of a supported charset
Throws:
UnsupportedEncodingException - If the named encoding is not supported

OutputStreamWriter

public OutputStreamWriter(OutputStream out)
Creates an OutputStreamWriter that uses the default character encoding.

Parameters:
out - An OutputStream

OutputStreamWriter

public OutputStreamWriter(OutputStream out,
                          Charset cs)
Creates an OutputStreamWriter that uses the given charset.

Parameters:
out - An OutputStream
cs - A charset
Since:
1.4

OutputStreamWriter

public OutputStreamWriter(OutputStream out,
                          CharsetEncoder enc)
Creates an OutputStreamWriter that uses the given charset encoder.

Parameters:
out - An OutputStream
enc - A charset encoder
Since:
1.4
Method Detail

getEncoding

public String getEncoding()
Returns the name of the character encoding being used by this stream.

If the encoding has an historical name then that name is returned; otherwise the encoding's canonical name is returned.

If this instance was created with the OutputStreamWriter(OutputStream, String) constructor then the returned name, being unique for the encoding, may differ from the name passed to the constructor. This method may return null if the stream has been closed.

Returns:
The historical name of this encoding, or possibly null if the stream has been closed
See Also:
Charset

write

public void write(int c)
           throws IOException
Writes a single character.

Overrides:
write in class Writer
Parameters:
c - int specifying a character to be written
Throws:
IOException - If an I/O error occurs

write

public void write(char[] cbuf,
                  int off,
                  int len)
           throws IOException
Writes a portion of an array of characters.

Specified by:
write in class Writer
Parameters:
cbuf - Buffer of characters
off - Offset from which to start writing characters
len - Number of characters to write
Throws:
IOException - If an I/O error occurs

write

public void write(String str,
                  int off,
                  int len)
           throws IOException
Writes a portion of a string.

Overrides:
write in class Writer
Parameters:
str - A String
off - Offset from which to start writing characters
len - Number of characters to write
Throws:
IOException - If an I/O error occurs

flush

public void flush()
           throws IOException
Flushes the stream.

Specified by:
flush in interface Flushable
Specified by:
flush in class Writer
Throws:
IOException - If an I/O error occurs

close

public void close()
           throws IOException
Description copied from class: Writer
Closes the stream, flushing it first. Once the stream has been closed, further write() or flush() invocations will cause an IOException to be thrown. Closing a previously closed stream has no effect.

Specified by:
close in interface Closeable
Specified by:
close in class Writer
Throws:
IOException - If an I/O error occurs

Java™ Platform
Standard Ed. 6

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For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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