- java.lang.Object
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- java.io.OutputStream
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- 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
OutputStreammust always provide at least a method that writes one byte of output.- Since:
- 1.0
- See Also:
BufferedOutputStream,ByteArrayOutputStream,DataOutputStream,FilterOutputStream,InputStream,write(int)
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Constructor Summary
Constructors Constructor Description OutputStream()
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Method Summary
All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description voidclose()Closes this output stream and releases any system resources associated with this stream.voidflush()Flushes this output stream and forces any buffered output bytes to be written out.static OutputStreamnullOutputStream()Returns a newOutputStreamwhich discards all bytes.voidwrite(byte[] b)Writesb.lengthbytes from the specified byte array to this output stream.voidwrite(byte[] b, int off, int len)Writeslenbytes from the specified byte array starting at offsetoffto this output stream.abstract voidwrite(int b)Writes the specified byte to this output stream.
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Method Detail
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nullOutputStream
public static OutputStream nullOutputStream()
Returns a newOutputStreamwhich 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
OutputStreamwhich discards all bytes - Since:
- 11
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write
public abstract void write(int b) throws IOExceptionWrites the specified byte to this output stream. The general contract forwriteis 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 ofbare ignored.Subclasses of
OutputStreammust provide an implementation for this method.- Parameters:
b- thebyte.- Throws:
IOException- if an I/O error occurs. In particular, anIOExceptionmay be thrown if the output stream has been closed.
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write
public void write(byte[] b) throws IOExceptionWritesb.lengthbytes 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(byte[], int, int)
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write
public void write(byte[] b, int off, int len) throws IOExceptionWriteslenbytes from the specified byte array starting at offsetoffto this output stream. The general contract forwrite(b, off, len)is that some of the bytes in the arraybare 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.The
writemethod ofOutputStreamcalls 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
bisnull, aNullPointerExceptionis thrown.If
offis negative, orlenis negative, oroff+lenis greater than the length of the arrayb, then anIndexOutOfBoundsExceptionis 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, anIOExceptionis thrown if the output stream is closed.
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flush
public void flush() throws IOExceptionFlushes this output stream and forces any buffered output bytes to be written out. The general contract offlushis 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
flushmethod ofOutputStreamdoes nothing.- Specified by:
flushin interfaceFlushable- Throws:
IOException- if an I/O error occurs.
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close
public void close() throws IOExceptionCloses this output stream and releases any system resources associated with this stream. The general contract ofcloseis that it closes the output stream. A closed stream cannot perform output operations and cannot be reopened.The
closemethod ofOutputStreamdoes nothing.- Specified by:
closein interfaceAutoCloseable- Specified by:
closein interfaceCloseable- Throws:
IOException- if an I/O error occurs.
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