Added in API level 1

Summary: Ctors | Methods | Protected Methods | Inherited Methods

FileOutputStream

public class FileOutputStream
extends OutputStream

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

Known direct subclasses

ParcelFileDescriptor.AutoCloseOutputStream

ParcelFileDescriptor.AutoCloseOutputStream An OutputStream you can create on a ParcelFileDescriptor, which will take care of calling ParcelFileDescriptor.close() for you when the stream is closed.

Known indirect subclasses

AssetFileDescriptor.AutoCloseOutputStream

AssetFileDescriptor.AutoCloseOutputStream An OutputStream you can create on a ParcelFileDescriptor, which will take care of calling ParcelFileDescriptor.close() for you when the stream is closed.

A file output stream is an output stream for writing data to a 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.

See also:

Summary

Public constructors
`FileOutputStream(File file)` Creates a file output stream to write to the file represented by the specified `File` object.
`FileOutputStream(File file, boolean append)` Creates a file output stream to write to the file represented by the specified `File` object.
`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(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.

Public methods
`void`	`close()` Closes this file output stream and releases any system resources associated with this stream.
`FileChannel`	`getChannel()` Returns the unique `FileChannel` object associated with this file output stream.
`final FileDescriptor`	`getFD()` Returns the file descriptor associated with this stream.
`void`	`write(byte[] b)` Writes `b.length` bytes from the specified byte array to this file output stream.
`void`	`write(byte[] b, int off, int len)` Writes `len` bytes from the specified byte array starting at offset `off` to this file output stream.
`void`	`write(int b)` Writes the specified byte to this file output stream.

Protected methods
`void`	`finalize()` Cleans up the connection to the file, and ensures that the `close` method of this file output stream is called when there are no more references to this stream.

Inherited methods

From class


        
          java.io.OutputStream

`void`	`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`	`nullOutputStream()` Returns a new `OutputStream` which discards all bytes.
`void`	`write(byte[] b)` Writes `b.length` bytes from the specified byte array to this output stream.
`void`	`write(byte[] b, int off, int len)` Writes `len` bytes from the specified byte array starting at offset `off` to this output stream.
`abstract void`	`write(int b)` Writes the specified byte to this output stream.

From class


        
          java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long timeoutMillis, int nanos)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait()` Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

From interface


        
          java.io.Closeable


      close()

Closes this stream and releases any system resources associated with it.

From interface


        
          java.io.Flushable


      flush()

Flushes this stream by writing any buffered output to the underlying stream.

From interface


        
          java.lang.AutoCloseable


      close()

Closes this resource, relinquishing any underlying resources.

Public constructors

FileOutputStream

Added in API level 1

public FileOutputStream (File file)

Creates a file output stream to write to the file represented by the specified File object. A new FileDescriptor object is created to represent this file connection.

First, if there is a security manager, its checkWrite method is called with the path represented by the file argument 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 FileNotFoundException is thrown.

Parameters
`file`	`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 `checkWrite` method denies write access to the file.

See also:

FileOutputStream

Added in API level 1

public FileOutputStream (File file, 
                boolean append)

Creates a file output stream to write to the file represented by the specified File object. If the second argument is true, then bytes will be written to the end of the file rather than the beginning. A new FileDescriptor object is created to represent this file connection.

First, if there is a security manager, its checkWrite method is called with the path represented by the file argument 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 FileNotFoundException is thrown.

Parameters
`file`	`File`: the file to be opened for writing.
`append`	`boolean`: 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 `checkWrite` method denies write access to the file.

See also:

FileOutputStream

Added in API level 1

public 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.

First, if there is a security manager, its checkWrite method is called with the file descriptor fdObj argument as its argument.

If fdObj is null then a NullPointerException is thrown.

This constructor does not throw an exception if fdObj is invalid. However, if the methods are invoked on the resulting stream to attempt I/O on the stream, an IOException is thrown.

Android-specific warning: close() method doesn't close the fdObj provided, because this object doesn't own the file descriptor, but the caller does. The caller can call Os.close(FileDescriptor) to close the fd.

Parameters
`fdObj`	`FileDescriptor`: the file descriptor to be opened for writing

Throws
`SecurityException`	if a security manager exists and its `checkWrite` method denies write access to the file descriptor

See also:

SecurityManager.checkWrite(java.io.FileDescriptor)

FileOutputStream

Added in API level 1

public FileOutputStream (String name)

Creates a file output stream to write to the file with the specified name. A new FileDescriptor object is created to represent this file connection.

First, if there is a security manager, its checkWrite method is called with name 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 FileNotFoundException is thrown.

Implementation Requirements:

Invoking this constructor with the parameter name is equivalent to invoking new FileOutputStream(name, false).

Parameters
`name`	`String`: 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 `checkWrite` method denies write access to the file.

See also:

SecurityManager.checkWrite(java.lang.String)

FileOutputStream

Added in API level 1

public FileOutputStream (String name, 
                boolean append)

Creates a file output stream to write to the file with the specified name. If the second argument is true, then bytes will be written to the end of the file rather than the beginning. A new FileDescriptor object is created to represent this file connection.

First, if there is a security manager, its checkWrite method is called with name 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 FileNotFoundException is thrown.

Parameters
`name`	`String`: the system-dependent file name
`append`	`boolean`: 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 `checkWrite` method denies write access to the file.

See also:

SecurityManager.checkWrite(java.lang.String)

Public methods

close

Added in API level 1

public void close ()

Closes 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.

API Note:

Overriding close() to perform cleanup actions is reliable only when called directly or when called by try-with-resources. Do not depend on finalization to invoke close; finalization is not reliable and is deprecated. If cleanup of native resources is needed, other mechanisms such as Cleaner should be used.

Throws
`IOException`	if an I/O error occurs.

getChannel

Added in API level 1

public FileChannel getChannel ()

Returns the unique FileChannel object associated with this file output stream.

The initial position of 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
`FileChannel`	the file channel associated with this file output stream

getFD

Added in API level 1

public final FileDescriptor getFD ()

Returns the file descriptor associated with this stream.

Returns
`FileDescriptor`	the `FileDescriptor` object that represents the connection to the file in the file system being used by this `FileOutputStream` object.

Throws
`IOException`	if an I/O error occurs.

See also:

FileDescriptor

write

Added in API level 1

public void write (byte[] b)

Writes b.length bytes from the specified byte array to this file output stream.

Parameters
`b`	`byte`: the data.

Throws
`IOException`	if an I/O error occurs.

write

Added in API level 1

public void write (byte[] b, 
                int off, 
                int len)

Writes len bytes from the specified byte array starting at offset off to this file output stream.

Parameters
`b`	`byte`: the data.
`off`	`int`: the start offset in the data.
`len`	`int`: the number of bytes to write.

Throws
`IOException`	if an I/O error occurs.

write

Added in API level 1

public void write (int b)

Writes the specified byte to this file output stream. Implements the write method of OutputStream.

Parameters
`b`	`int`: the byte to be written.

Throws
`IOException`	if an I/O error occurs.

Protected methods

finalize

Added in API level 1

protected void finalize ()

Cleans up the connection to the file, and ensures that the close method of this file output stream is called when there are no more references to this stream.

Throws
`IOException`	if an I/O error occurs.

See also:

FileInputStream.close()