Package java.io

Class FileOutputStream

java.lang.Object

java.io.OutputStream

java.io.FileOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

Direct Known Subclasses:

ParcelFileDescriptor.AutoCloseOutputStream

public class FileOutputStream
extends OutputStream

An output stream that writes bytes to a file. If the output file exists, it can be replaced or appended to. If it does not exist, a new file will be created.

   
   File file = ...
   OutputStream out = null;
   try {
     out = new BufferedOutputStream(new FileOutputStream(file));
     ...
   } finally {
     if (out != null) {
       out.close();
     }
   }
 

This stream is not buffered. Most callers should wrap this stream with a BufferedOutputStream.

Use FileWriter to write characters, as opposed to bytes, to a file.

See Also:

BufferedOutputStream, FileInputStream

Constructor Summary

Constructors

Constructor	Description
FileOutputStream(File file)	Constructs a new FileOutputStream that writes to file.
FileOutputStream(FileDescriptor fd)	Constructs a new FileOutputStream that writes to fd.
FileOutputStream(File file, boolean append)	Constructs a new FileOutputStream that writes to file.
FileOutputStream(String path)	Constructs a new FileOutputStream that writes to path.
FileOutputStream(String path, boolean append)	Constructs a new FileOutputStream that writes to path.

Method Summary

Modifier and Type	Method	Description
void	close()	Closes this stream.
protected void	finalize()	Invoked when the garbage collector has detected that this instance is no longer reachable.
FileChannel	getChannel()	Returns a write-only FileChannel that shares its position with this stream.
FileDescriptor	getFD()	Returns the underlying file descriptor.
void	write(byte[] buffer, int byteOffset, int byteCount)	Writes count bytes from the byte array buffer starting at position offset to this stream.
void	write(int oneByte)	Writes a single byte to this stream.

Methods inherited from class java.io.OutputStream

flush, write

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 that writes to file. The file will be truncated if it exists, and created if it doesn't exist.

Throws:

FileNotFoundException - if file cannot be opened for writing.

FileOutputStream

public FileOutputStream(File file,
                        boolean append)
                 throws FileNotFoundException

Constructs a new FileOutputStream that writes to file. If append is true and the file already exists, it will be appended to; otherwise it will be truncated. The file will be created if it does not exist.

Throws:

FileNotFoundException - if the file cannot be opened for writing.

FileOutputStream

public FileOutputStream(FileDescriptor fd)

Constructs a new FileOutputStream that writes to fd.

Throws:

NullPointerException - if fd is null.

FileOutputStream

public FileOutputStream(String path)
                 throws FileNotFoundException

Constructs a new FileOutputStream that writes to path. The file will be truncated if it exists, and created if it doesn't exist.

Throws:

FileNotFoundException - if file cannot be opened for writing.

FileOutputStream

public FileOutputStream(String path,
                        boolean append)
                 throws FileNotFoundException

Constructs a new FileOutputStream that writes to path. If append is true and the file already exists, it will be appended to; otherwise it will be truncated. The file will be created if it does not exist.

Throws:

FileNotFoundException - if the file cannot be opened for writing.

Method Detail

close

public void close()
           throws IOException

Description copied from class: OutputStream

Closes this stream. Implementations of this method should free any resources used by the stream. This implementation does nothing.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class OutputStream

Throws:

IOException - if an error occurs while closing this stream.

finalize

protected void finalize()
                 throws IOException

Description copied from class: Object

Invoked when the garbage collector has detected that this instance is no longer reachable. The default implementation does nothing, but this method can be overridden to free resources.

Note that objects that override finalize are significantly more expensive than objects that don't. Finalizers may be run a long time after the object is no longer reachable, depending on memory pressure, so it's a bad idea to rely on them for cleanup. Note also that finalizers are run on a single VM-wide finalizer thread, so doing blocking work in a finalizer is a bad idea. A finalizer is usually only necessary for a class that has a native peer and needs to call a native method to destroy that peer. Even then, it's better to provide an explicit close method (and implement Closeable), and insist that callers manually dispose of instances. This works well for something like files, but less well for something like a BigInteger where typical calling code would have to deal with lots of temporaries. Unfortunately, code that creates lots of temporaries is the worst kind of code from the point of view of the single finalizer thread.

If you must use finalizers, consider at least providing your own ReferenceQueue and having your own thread process that queue.

Unlike constructors, finalizers are not automatically chained. You are responsible for calling super.finalize() yourself.

Uncaught exceptions thrown by finalizers are ignored and do not terminate the finalizer thread. See Effective Java Item 7, "Avoid finalizers" for more.

Overrides:

finalize in class Object

Throws:

IOException

getChannel

public FileChannel getChannel()

Returns a write-only FileChannel that shares its position with this stream.

getFD

public final FileDescriptor getFD()
                           throws IOException

Returns the underlying file descriptor.

Throws:

IOException

write

public void write(byte[] buffer,
                  int byteOffset,
                  int byteCount)
           throws IOException

Description copied from class: OutputStream

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

Overrides:

write in class OutputStream

Parameters:

buffer - the buffer to be written.

byteOffset - the start position in buffer from where to get bytes.

byteCount - the number of bytes from buffer to write to this stream.

Throws:

IOException - if an error occurs while writing to this stream.

write

public void write(int oneByte)
           throws IOException

Description copied from class: OutputStream

Writes a single byte to this stream. Only the least significant byte of the integer oneByte is written to the stream.

Specified by:

write in class OutputStream

Parameters:

oneByte - the byte to be written.

Throws:

IOException - if an error occurs while writing to this stream.