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OutputStreamWriter (Java SE 26 & JDK 26)

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java.lang.Object

java.io.Writer

java.io.OutputStreamWriter

All Implemented Interfaces: Closeable, Flushable, Appendable, AutoCloseable 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 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. 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:

Copy Writer out = new BufferedWriter(new OutputStreamWriter(anOutputStream));

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: 1.1 See Also:

Field Summary

Fields declared in class Writer
lock

Modifier and Type

Field

Description

protected Object

lock

The object used to synchronize operations on this stream.
Constructor Summary

Constructors

Constructor

Description

OutputStreamWriter(OutputStream out)

Creates an OutputStreamWriter that uses the default character encoding, or where out is a PrintStream, the charset used by the print stream.

OutputStreamWriter(OutputStream out, String charsetName)

Creates an OutputStreamWriter that uses the named charset.

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.
Method Summary

All MethodsInstance MethodsConcrete Methods

Modifier and Type

Method

Description

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 declared in class Writer
append, append, append, nullWriter, write, write

Modifier and Type

Method

Description

Writer

append(char c)

Appends the specified character to this writer.

Writer

append(CharSequence csq)

Appends the specified character sequence to this writer.

Writer

append(CharSequence csq, int start, int end)

Appends a subsequence of the specified character sequence to this writer.

static Writer

nullWriter()

Returns a new Writer which discards all characters.

void

write(char[] cbuf)

Writes an array of characters.

void

write(String str)

Writes a string.

Methods declared in class Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Modifier and Type

Method

Description

protected Object

clone()

Creates and returns a copy of this object.

boolean

equals(Object obj)

Indicates whether some other object is "equal to" this one.

protected void

finalize()

Deprecated, for removal: This API element is subject to removal in a future version.
Finalization is deprecated and subject to removal in a future release.

final Class<?>

getClass()

Returns the runtime class of this Object.

int

hashCode()

Returns a hash code value for this object.

final void

notify()

Wakes up a single thread that is waiting on this object's monitor.

final void

notifyAll()

Wakes up all threads that are waiting on this object's monitor.

String

toString()

Returns a string representation of the object.

final void

wait()

Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

final void

wait(long timeoutMillis)

Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

final void

wait(long timeoutMillis, int nanos)

Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Constructor Details
- 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, or where out is a PrintStream, the charset used by the print stream.
  Parameters: out - An OutputStream See Also:
  - Charset.defaultCharset()
- 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 Details
- 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: IndexOutOfBoundsException - If off is negative, or len is negative, or off + len is negative or greater than the length of the given array 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: IndexOutOfBoundsException - If off is negative, or len is negative, or off + len is negative or greater than the length of the given string 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 AutoCloseable Specified by: close in interface Closeable Specified by: close in class Writer Throws: IOException - If an I/O error occurs

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Class OutputStreamWriter

Field Summary

Fields declared in class Writer

Constructor Summary

Method Summary

Methods declared in class Writer

Methods declared in class Object

Constructor Details

OutputStreamWriter

OutputStreamWriter

OutputStreamWriter

OutputStreamWriter

Method Details

getEncoding

write

write

write

flush

close