Class OutputStream
- java.lang.Object
-
- java.io.OutputStream
- All Implemented Interfaces:
-
Closeable
,Flushable
,AutoCloseable
- Direct Known Subclasses:
-
ByteArrayOutputStream
,FileOutputStream
,FilterOutputStream
,ObjectOutputStream
,PipedOutputStream
public abstract class OutputStream extends Object implements Closeable, Flushable
This abstract class is the superclass of all classes representing an output stream of bytes. An output stream accepts output bytes and sends them to some sink.
Applications that need to define a subclass of OutputStream
must always provide at least a method that writes one byte of output.
- Since:
- 1.0
- See Also:
-
BufferedOutputStream
,ByteArrayOutputStream
,DataOutputStream
,FilterOutputStream
,InputStream
,write(int)
Constructor Summary
Constructor | Description |
---|---|
OutputStream() |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
void | close() | Closes this output stream and releases any system resources associated with this stream. |
void | flush() | Flushes this output stream and forces any buffered output bytes to be written out. |
static OutputStream | nullOutputStream() | Returns a new |
void | write(byte[] b) | Writes |
void | write(byte[] b,
int off,
int len) | Writes |
abstract void | write(int b) | Writes the specified byte to this output stream. |
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Constructor Detail
OutputStream
public OutputStream()
Method Detail
nullOutputStream
public static OutputStream nullOutputStream()
Returns a new OutputStream
which discards all bytes. The returned stream is initially open. The stream is closed by calling the close()
method. Subsequent calls to close()
have no effect.
While the stream is open, the write(int)
,
write(byte[])
, and write(byte[], int, int)
methods do nothing. After the stream has been closed, these methods all throw
IOException
.
The flush()
method does nothing.
- Returns:
- an
OutputStream
which discards all bytes - Since:
- 11
write
public abstract void write(int b) throws IOException
Writes the specified byte to this output stream. The general contract for write
is that one byte is written to the output stream. The byte to be written is the eight low-order bits of the argument b
. The 24 high-order bits of b
are ignored.
Subclasses of OutputStream
must provide an implementation for this method.
- Parameters:
-
b
- thebyte
. - Throws:
-
IOException
- if an I/O error occurs. In particular, anIOException
may be thrown if the output stream has been closed.
write
public void write(byte[] b) throws IOException
Writes b.length
bytes from the specified byte array to this output stream. The general contract for write(b)
is that it should have exactly the same effect as the call write(b, 0, b.length)
.
- Parameters:
-
b
- the data. - Throws:
-
IOException
- if an I/O error occurs. - See Also:
write(byte[], int, int)
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 general contract for write(b, off, len)
is that some of the bytes in the array b
are written to the output stream in order; element b[off]
is the first byte written and b[off+len-1]
is the last byte written by this operation.
The write
method of OutputStream
calls the write method of one argument on each of the bytes to be written out. Subclasses are encouraged to override this method and provide a more efficient implementation.
If b
is null
, a NullPointerException
is thrown.
If off
is negative, or len
is negative, or off+len
is greater than the length of the array b
, then an IndexOutOfBoundsException
is thrown.
- 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. In particular, anIOException
is thrown if the output stream is closed.
flush
public void flush() throws IOException
Flushes this output stream and forces any buffered output bytes to be written out. The general contract of flush
is that calling it is an indication that, if any bytes previously written have been buffered by the implementation of the output stream, such bytes should immediately be written to their intended destination.
If the intended destination of this stream is an abstraction provided by the underlying operating system, for example a file, then flushing the stream guarantees only that bytes previously written to the stream are passed to the operating system for writing; it does not guarantee that they are actually written to a physical device such as a disk drive.
The flush
method of OutputStream
does nothing.
- Specified by:
-
flush
in interfaceFlushable
- Throws:
-
IOException
- if an I/O error occurs.
close
public void close() throws IOException
Closes this output stream and releases any system resources associated with this stream. The general contract of close
is that it closes the output stream. A closed stream cannot perform output operations and cannot be reopened.
The close
method of OutputStream
does nothing.
- Specified by:
-
close
in interfaceAutoCloseable
- Specified by:
-
close
in interfaceCloseable
- Throws:
-
IOException
- if an I/O error occurs.