Class OutputStream
- All Implemented Interfaces:
Closeable
,Flushable
,AutoCloseable
- Direct Known Subclasses:
ByteArrayOutputStream
,FileOutputStream
,FilterOutputStream
,ObjectOutputStream
,PipedOutputStream
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:
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionvoid
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
Returns a newOutputStream
which discards all bytes.void
write
(byte[] b) Writesb.length
bytes from the specified byte array to this output stream.void
write
(byte[] b, int off, int len) Writeslen
bytes from the specified byte array starting at offsetoff
to this output stream.abstract void
write
(int b) Writes the specified byte to this output stream.
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Constructor Details
-
OutputStream
public OutputStream()Constructor for subclasses to call.
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Method Details
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nullOutputStream
Returns a newOutputStream
which discards all bytes. The returned stream is initially open. The stream is closed by calling theclose()
method. Subsequent calls toclose()
have no effect.While the stream is open, the
write(int)
,write(byte[])
, andwrite(byte[], int, int)
methods do nothing. After the stream has been closed, these methods all throwIOException
.The
flush()
method does nothing.- Returns:
- an
OutputStream
which discards all bytes - Since:
- 11
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write
Writes the specified byte to this output stream. The general contract forwrite
is that one byte is written to the output stream. The byte to be written is the eight low-order bits of the argumentb
. The 24 high-order bits ofb
are ignored.- Parameters:
b
- thebyte
.- Throws:
IOException
- if an I/O error occurs. In particular, anIOException
may be thrown if the output stream has been closed.
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write
Writesb.length
bytes from the specified byte array to this output stream. The general contract forwrite(b)
is that it should have exactly the same effect as the callwrite(b, 0, b.length)
.- Parameters:
b
- the data.- Throws:
IOException
- if an I/O error occurs.- See Also:
-
write
Writeslen
bytes from the specified byte array starting at offsetoff
to this output stream. The general contract forwrite(b, off, len)
is that some of the bytes in the arrayb
are written to the output stream in order; elementb[off]
is the first byte written andb[off+len-1]
is the last byte written by this operation.If
b
isnull
, aNullPointerException
is thrown.If
off
is negative, orlen
is negative, oroff+len
is greater than the length of the arrayb
, then anIndexOutOfBoundsException
is thrown.- API Note:
- Subclasses are encouraged to override this method and provide a more efficient implementation.
- Implementation Requirements:
- The
write
method ofOutputStream
calls the write method of one argument on each of the bytes to be written out. - 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.IndexOutOfBoundsException
- Ifoff
is negative,len
is negative, orlen
is greater thanb.length - off
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flush
Flushes this output stream and forces any buffered output bytes to be written out. The general contract offlush
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.
- Specified by:
flush
in interfaceFlushable
- Implementation Requirements:
- The
flush
method ofOutputStream
does nothing. - Throws:
IOException
- if an I/O error occurs.
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close
Closes this output stream and releases any system resources associated with this stream. The general contract ofclose
is that it closes the output stream. A closed stream cannot perform output operations and cannot be reopened.- Specified by:
close
in interfaceAutoCloseable
- Specified by:
close
in interfaceCloseable
- Implementation Requirements:
- The
close
method ofOutputStream
does nothing. - Throws:
IOException
- if an I/O error occurs.
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