Chapter 11
The java.io Package

OutputStreamWriter

Name

OutputStreamWriter

Synopsis

Class Name:

java.io.OutputStreamWriter

Superclass:

java.io.Writer

Immediate Subclasses:

java.io.FileWriter

Interfaces Implemented:

None

Availability:

New as of JDK 1.1

The OutputStreamWriter class is a bridge between the byte-oriented world of the OutputStream class and the character-oriented world of the Writer class. The OutputStreamWriter represents a character stream, but it sends its output to an underlying byte stream. A character encoding scheme is responsible for translating the Unicode characters to bytes. An OutputStreamWriter can be created using an explicit encoding scheme or a default encoding scheme.

For example, to write a Unicode character stream as an ISO-8859-5 byte stream, you can construct an OutputStreamWriter with the encoding 8859_5 as follows:

OutputStreamWriter outr = new OutputStreamWriter(out, "8859_5");

Each time you write to an OutputStreamWriter object, bytes may be written to the underlying byte stream. To improve efficiency, you may want to wrap the OutputStreamWriter in a BufferedWriter.

Class Summary

public class java.io.OutputStreamWriter extends java.io.Writer {
  // Constructors
  public OutputStreamWriter(OutputStream out);
  public OutputStreamWriter(OutputStream out, String enc);
  // Instance Methods
  public void close();
  public void flush();
  public String getEncoding();
  public void write(int c);
  public void write(char[] cbuf, int off, int len);
  public void write(String str, int off, int len);
}

Constructors

OutputStreamWriter

public OutputStreamWriter(OutputStream out)

Parameters

out: The output stream to use.

Description

This constructor creates an OutputStreamWriter that writes its data to out and translates characters to bytes using the system's default encoding scheme.

 public OutputStreamWriter(OutputStream out, String enc) throws UnsupportedEncodingException

Parameters

out

The output stream to use.

enc

The name of an encoding scheme.

Throws

UnsupportedEncodingException: If enc is not a supported encoding scheme.

Description

This constructor creates an OutputStreamWriter that writes its data to out and translates characters to bytes using the given encoding scheme.

Instance Methods

close

public void close() throws IOException

Throws

IOException: If any kind of I/O error occurs.

Overrides

Writer.close()

Description

This method calls the close() method of the underlying output stream, which releases any system resources associated with this object.

flush

public void flush() throws IOException

Throws

IOException: If any kind of I/O error occurs.

Overrides

Writer.flush()

Description

This method writes out any buffered data in the internal buffer and calls the flush() method of the underlying output stream, which forces any bytes that may be buffered to be written to the underlying device.

getEncoding

public String getEncoding()

Returns

A String that contains the name of the character encoding scheme of this writer.

Description

This method returns the name of the character encoding scheme this OutputStreamWriter is currently using.

write

public void write(int c) throws IOException

Parameters

c: The value to write.

Throws

IOException: If any kind of I/O error occurs.

Overrides

Writer.write(int)

Description

This method converts the given character to bytes using the current encoding scheme and places the converted bytes into an internal buffer. When the buffer fills up, it is written to the underlying byte stream.

 public void write(char[] cbuf, int off, int len) throws IOException

Parameters

cbuf

An array of characters to write.

off

An offset into the character array.

len

The number of characters to write.

Throws

IOException: If any kind of I/O error occurs.

Overrides

Writer.write(char[], int, int)

Description

This method converts len characters from the array cbuf to bytes, starting at offset off, using the current encoding scheme. The method places the converted bytes into an internal buffer. When the buffer fills up, it is written to the underlying byte stream.

public void write(String str, int off, int len) throws IOException

Parameters

str

The string to be written.

off

An offset into start in the string.

len

The number of characters to write.

Throws

IOException: If any kind of I/O error occurs.

Overrides

Writer.write(String, int, int)

Description

This method converts len characters from the string str to bytes, starting at offset off, using the current encoding scheme. The method places the converted bytes into an internal buffer. When the buffer fills up, it is written to the underlying byte stream.

Inherited Methods

Method	Inherited From	Method	Inherited From
`clone()`	`Object`	`equals(Object)`	`Object`
`finalize()`	`Object`	`getClass()`	`Object`
`hashCode()`	`Object`	`notify()`	`Object`
`notifyAll()`	`Object`	`toString()`	`Object`
`wait()`	`Object`	`wait(long)`	`Object`
`wait(long, int)`	`Object`	`write(char[])`	`Writer`
`write(String)`	`Writer`