- All Implemented Interfaces:
- Closeable,- Flushable,- AutoCloseable
File or to a FileDescriptor. Whether or not
 a file is available or may be created depends upon the underlying
 platform.  Some platforms, in particular, allow a file to be opened
 for writing by only one FileOutputStream (or other
 file-writing object) at a time.  In such situations the constructors in
 this class will fail if the file involved is already open.
 FileOutputStream is meant for writing streams of raw bytes
 such as image data. For writing streams of characters, consider using
 FileWriter.
- API Note:
- The close()method should be called to release resources used by this stream, either directly, or with thetry-with-resources statement.
- Implementation Requirements:
- Subclasses are responsible for the cleanup of resources acquired by the subclass.
 Subclasses requiring that resource cleanup take place after a stream becomes
 unreachable should use Cleaneror some other mechanism.
- Since:
- 1.0
- See Also:
- 
Constructor SummaryConstructorsConstructorDescriptionFileOutputStream(File file) Creates a file output stream to write to the file represented by the specifiedFileobject.FileOutputStream(FileDescriptor fdObj) Creates a file output stream to write to the specified file descriptor, which represents an existing connection to an actual file in the file system.FileOutputStream(File file, boolean append) Creates a file output stream to write to the file represented by the specifiedFileobject.FileOutputStream(String name) Creates a file output stream to write to the file with the specified name.FileOutputStream(String name, boolean append) Creates a file output stream to write to the file with the specified name.
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Method SummaryModifier and TypeMethodDescriptionvoidclose()Closes this file output stream and releases any system resources associated with this stream.Returns the uniqueFileChannelobject associated with this file output stream.final FileDescriptorgetFD()Returns the file descriptor associated with this stream.voidwrite(byte[] b) Writesb.lengthbytes from the specified byte array to this file output stream.voidwrite(byte[] b, int off, int len) Writeslenbytes from the specified byte array starting at offsetoffto this file output stream.voidwrite(int b) Writes the specified byte to this file output stream.Methods declared in class java.io.OutputStreamflush, nullOutputStream
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Constructor Details- 
FileOutputStreamCreates a file output stream to write to the file with the specified name. A newFileDescriptorobject is created to represent this file connection.First, if there is a security manager, its checkWritemethod is called withnameas its argument.If the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason then a FileNotFoundExceptionis thrown.- Implementation Requirements:
- Invoking this constructor with the parameter nameis equivalent to invokingnew FileOutputStream(name, false).
- Parameters:
- name- the system-dependent filename
- Throws:
- FileNotFoundException- if the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason
- SecurityException- if a security manager exists and its- checkWritemethod denies write access to the file.
- See Also:
 
- 
FileOutputStreamCreates a file output stream to write to the file with the specified name. If the second argument istrue, then bytes will be written to the end of the file rather than the beginning. A newFileDescriptorobject is created to represent this file connection.First, if there is a security manager, its checkWritemethod is called withnameas its argument.If the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason then a FileNotFoundExceptionis thrown.- Parameters:
- name- the system-dependent file name
- append- if- true, then bytes will be written to the end of the file rather than the beginning
- Throws:
- FileNotFoundException- if the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason.
- SecurityException- if a security manager exists and its- checkWritemethod denies write access to the file.
- Since:
- 1.1
- See Also:
 
- 
FileOutputStreamCreates a file output stream to write to the file represented by the specifiedFileobject. A newFileDescriptorobject is created to represent this file connection.First, if there is a security manager, its checkWritemethod is called with the path represented by thefileargument as its argument.If the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason then a FileNotFoundExceptionis thrown.- Parameters:
- file- the file to be opened for writing.
- Throws:
- FileNotFoundException- if the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason
- SecurityException- if a security manager exists and its- checkWritemethod denies write access to the file.
- See Also:
 
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FileOutputStreamCreates a file output stream to write to the file represented by the specifiedFileobject. If the second argument istrue, then bytes will be written to the end of the file rather than the beginning. A newFileDescriptorobject is created to represent this file connection.First, if there is a security manager, its checkWritemethod is called with the path represented by thefileargument as its argument.If the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason then a FileNotFoundExceptionis thrown.- Parameters:
- file- the file to be opened for writing.
- append- if- true, then bytes will be written to the end of the file rather than the beginning
- Throws:
- FileNotFoundException- if the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason
- SecurityException- if a security manager exists and its- checkWritemethod denies write access to the file.
- Since:
- 1.4
- See Also:
 
- 
FileOutputStreamCreates a file output stream to write to the specified file descriptor, which represents an existing connection to an actual file in the file system.First, if there is a security manager, its checkWritemethod is called with the file descriptorfdObjargument as its argument.If fdObjis null then aNullPointerExceptionis thrown.This constructor does not throw an exception if fdObjisinvalid. However, if the methods are invoked on the resulting stream to attempt I/O on the stream, anIOExceptionis thrown.- Parameters:
- fdObj- the file descriptor to be opened for writing
- Throws:
- SecurityException- if a security manager exists and its- checkWritemethod denies write access to the file descriptor
- See Also:
 
 
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Method Details- 
writeWrites the specified byte to this file output stream. Implements thewritemethod ofOutputStream.- Specified by:
- writein class- OutputStream
- Parameters:
- b- the byte to be written.
- Throws:
- IOException- if an I/O error occurs.
 
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writeWritesb.lengthbytes from the specified byte array to this file output stream.- Overrides:
- writein class- OutputStream
- Parameters:
- b- the data.
- Throws:
- IOException- if an I/O error occurs.
- See Also:
 
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writeWriteslenbytes from the specified byte array starting at offsetoffto this file output stream.- Overrides:
- writein class- OutputStream
- 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.
- IndexOutOfBoundsException- If- offis negative,- lenis negative, or- lenis greater than- b.length - off
 
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closeCloses this file output stream and releases any system resources associated with this stream. This file output stream may no longer be used for writing bytes.If this stream has an associated channel then the channel is closed as well. - Specified by:
- closein interface- AutoCloseable
- Specified by:
- closein interface- Closeable
- Overrides:
- closein class- OutputStream
- API Note:
- Overriding close()to perform cleanup actions is reliable only when called directly or when called by try-with-resources.
- Implementation Requirements:
- Subclasses requiring that resource cleanup take place after a stream becomes
 unreachable should use the Cleanermechanism.If this stream has an associated channel then this method will close the channel, which in turn will close this stream. Subclasses that override this method should be prepared to handle possible reentrant invocation. 
- Throws:
- IOException- if an I/O error occurs.
 
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getFDReturns the file descriptor associated with this stream.- Returns:
- the FileDescriptorobject that represents the connection to the file in the file system being used by thisFileOutputStreamobject.
- Throws:
- IOException- if an I/O error occurs.
- See Also:
 
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getChannelReturns the uniqueFileChannelobject associated with this file output stream.The initial positionof the returned channel will be equal to the number of bytes written to the file so far unless this stream is in append mode, in which case it will be equal to the size of the file. Writing bytes to this stream will increment the channel's position accordingly. Changing the channel's position, either explicitly or by writing, will change this stream's file position.- Returns:
- the file channel associated with this file output stream
- Since:
- 1.4
 
 
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