java.io
Class FileOutputStream

java.lang.Object
  java.io.OutputStream
      java.io.FileOutputStream

public class FileOutputStream
extends OutputStream

FileOutputStream is a class whose underlying stream is represented by a file in the operating system. The bytes that are written to this stream are passed directly to the underlying operating system equivalent function. Since overhead may be high in writing to the OS, FileOutputStreams are usually wrapped with a BufferedOutputStream to reduce the number of times the OS is called.

BufferedOutputStream buf = new BufferedOutputStream(new FileOutputStream("aFile.txt"));

See Also:

FileInputStream

Constructor Summary

FileOutputStream(File file)
Constructs a new FileOutputStream on the File file.

FileOutputStream(File file, boolean append)
Constructs a new FileOutputStream on the File file.

FileOutputStream(FileDescriptor fd)
Constructs a new FileOutputStream on the FileDescriptor fd.

FileOutputStream(String filename)
Constructs a new FileOutputStream on the file named fileName.

FileOutputStream(String filename, boolean append)
Constructs a new FileOutputStream on the file named filename.

Method Summary

void	close() Close the FileOutputStream.
protected void	finalize() Frees any resources allocated to represent this FileOutputStream before it is garbage collected.
FileChannel	getChannel() Answers the FileChannel equivalent to this output stream.
FileDescriptor	getFD() Answers a FileDescriptor which represents the lowest level representation of a OS stream resource.
void	write(byte[] buffer) Writes the entire contents of the byte array buffer to this FileOutputStream.
void	write(byte[] buffer, int offset, int count) Writes count bytes from the byte array buffer starting at offset to this FileOutputStream.
void	write(int oneByte) Writes the specified byte oneByte to this FileOutputStream.

Methods inherited from class java.io.OutputStream

flush

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FileOutputStream

public FileOutputStream(File file)
                 throws FileNotFoundException

Constructs a new FileOutputStream on the File file. If the file exists, it is written over. See the constructor which can append to the file if so desired.

Parameters:

file - the File on which to stream reads.

Throws:

FileNotFoundException - If the file cannot be opened for writing.

See Also:

SecurityManager.checkWrite(FileDescriptor)

FileOutputStream

public FileOutputStream(File file,
                        boolean append)
                 throws FileNotFoundException

Constructs a new FileOutputStream on the File file. If the file exists, it is written over. The parameter append determines whether or not the file is opened and appended to or just opened empty.

Parameters:

file - the File on which to stream reads.

append - a boolean indicating whether or not to append to an existing file.

Throws:

FileNotFoundException - If the file cannot be opened for writing.

See Also:

SecurityManager.checkWrite(FileDescriptor), SecurityManager.checkWrite(String)

FileOutputStream

public FileOutputStream(FileDescriptor fd)

Constructs a new FileOutputStream on the FileDescriptor fd. The file must already be open, therefore no FileIOException will be thrown.

Parameters:

fd - the FileDescriptor on which to stream writes.

See Also:

SecurityManager.checkWrite(FileDescriptor)

FileOutputStream

public FileOutputStream(String filename)
                 throws FileNotFoundException

Constructs a new FileOutputStream on the file named fileName. If the file exists, it is written over. See the constructor which can append to the file if so desired. The fileName may be absolute or relative to the System property "user.dir".

Parameters:

filename - the file on which to stream writes.

Throws:

FileNotFoundException - If the filename cannot be opened for writing.

FileOutputStream

public FileOutputStream(String filename,
                        boolean append)
                 throws FileNotFoundException

Constructs a new FileOutputStream on the file named filename. If the file exists, it is written over. The parameter append determines whether or not the file is opened and appended to or just opened empty. The filename may be absolute or relative to the System property "user.dir".

Parameters:

filename - the file on which to stream writes.

append - a boolean indicating whether or not to append to an existing file.

Throws:

FileNotFoundException - If the filename cannot be opened for writing.

Method Detail

close

public void close()
           throws IOException

Close the FileOutputStream. This implementation closes the underlying OS resources allocated to represent this stream.

Overrides:

close in class OutputStream

Throws:

IOException - If an error occurs attempting to close this FileOutputStream.

finalize

protected void finalize()
                 throws IOException

Frees any resources allocated to represent this FileOutputStream before it is garbage collected. This method is called from the Java Virtual Machine.

Overrides:

finalize in class Object

Throws:

IOException - If an error occurs attempting to finalize this FileOutputStream.

getChannel

public FileChannel getChannel()

Answers the FileChannel equivalent to this output stream.

The file channel is write-only and has an initial position within the file that is the same as the current position of this FileOutputStream within the file. All changes made to the underlying file descriptor state via the channel are visible by the output stream and vice versa.

Returns:

the file channel representation for this FileOutputStream.

getFD

public final FileDescriptor getFD()
                           throws IOException

Answers a FileDescriptor which represents the lowest level representation of a OS stream resource.

Returns:

a FileDescriptor representing this FileOutputStream.

Throws:

IOException - If the Stream is already closed and there is no FileDescriptor.

write

public void write(byte[] buffer)
           throws IOException

Writes the entire contents of the byte array buffer to this FileOutputStream.

Overrides:

write in class OutputStream

Parameters:

buffer - the buffer to be written

Throws:

IOException - If an error occurs attempting to write to this FileOutputStream.

write

public void write(byte[] buffer,
                  int offset,
                  int count)
           throws IOException

Writes count bytes from the byte array buffer starting at offset to this FileOutputStream.

Overrides:

write in class OutputStream

Parameters:

buffer - the buffer to be written

offset - offset in buffer to get bytes

count - number of bytes in buffer to write

Throws:

IOException - If an error occurs attempting to write to this FileOutputStream.

IndexOutOfBoundsException - If offset or count are outside of bounds.

NullPointerException - If buffer is null.

write

public void write(int oneByte)
           throws IOException

Writes the specified byte oneByte to this FileOutputStream. Only the low order byte of oneByte is written.

Specified by:

write in class OutputStream

Parameters:

oneByte - the byte to be written

Throws:

IOException - If an error occurs attempting to write to this FileOutputStream.