Class java.io.FilterOutputStream - JDK 5 Documentation v1.1.8, Java 2 SDK 英文文档

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Class java.io.FilterOutputStream

java.lang.Object
   |
   +----java.io.OutputStream
           |
           +----java.io.FilterOutputStream

public class FilterOutputStream
extends OutputStream

This class is the superclass of all classes that filter output streams. These streams sit on top of an already existing output stream (the underlying output stream), but provide additional functionality.

The class FilterOutputStream itself simply overrides all methods of OutputStream with versions that pass all requests to the underlying output stream. Subclasses of FilterOutputStream may further override some of these methods as well as provide additional methods and fields.

out: The underlying output stream.

FilterOutputStream(OutputStream): Creates an output stream filter built on top of the specified underlying output stream.

close(): Closes this output stream and releases any system resources associated with the stream.
flush(): Flushes this output stream and forces any buffered output bytes to be written out to the stream.
write(byte[]): Writes b.length bytes to this output stream.
write(byte[], int, int): Writes len bytes from the specified byte array starting at offset off to this output stream.
write(int): Writes the specified byte to this output stream.

out

 protected OutputStream out

The underlying output stream.

FilterOutputStream

 public FilterOutputStream(OutputStream out)

Creates an output stream filter built on top of the specified underlying output stream.

Parameters:: out - the underlying output stream.

write

 public void write(int b) throws IOException

Writes the specified byte to this output stream.

The write method of FilterOutputStream calls the write method of its underlying output stream.

Parameters:: b - the byte.
Throws: IOException: if an I/O error occurs.
Overrides:: write in class OutputStream

write

 public void write(byte b[]) throws IOException

Writes b.length bytes to this output stream.

The write method of FilterOutputStream calls its write method of three arguments with the arguments b, 0, and b.length.

Note that this method does not call the one-argument write method of its underlying stream with the single argument b.

Parameters:: b - the data to be written.
Throws: IOException: if an I/O error occurs.
Overrides:: write in class OutputStream
See Also:: write

write

 public void write(byte b[],
                   int off,
                   int len) throws IOException

Writes len bytes from the specified byte array starting at offset off to this output stream.

The write method of FilterOutputStream calls the write method of one argument on each byte to output.

Note that this method does not call the write method of its underlying input stream with the same arguments. Subclasses of FilterOutputStream should provide a more efficient implementation of this method.

Parameters:: b - the data.; off - the start offset in the data.; len - the number of bytes to write.
Throws: IOException: if an I/O error occurs.
Overrides:: write in class OutputStream
See Also:: write

flush

 public void flush() throws IOException

Flushes this output stream and forces any buffered output bytes to be written out to the stream.

The flush method of FilterOutputStream calls the flush method of its underlying output stream.

Throws: IOException: if an I/O error occurs.
Overrides:: flush in class OutputStream
See Also:: out

close

 public void close() throws IOException

Closes this output stream and releases any system resources associated with the stream.

The close method of FilterOutputStream calls its flush method, and then calls the close method of its underlying output stream.

Throws: IOException: if an I/O error occurs.
Overrides:: close in class OutputStream
See Also:: flush, out

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