Added in API level 1

FileOutputStream

open class FileOutputStream : OutputStream

kotlin.Any
↳	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 android.

Known Indirect Subclasses AssetFileDescriptor.AutoCloseOutputStream AssetFileDescriptor.AutoCloseOutputStream An OutputStream you can create on a ParcelFileDescriptor, which will take care of calling android.

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.

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!, append: Boolean) Creates a file output stream to write to the file represented by the specified File object.
FileOutputStream(fdObj: FileDescriptor!) 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(name: String!) Creates a file output stream to write to the file with the specified name.
FileOutputStream(name: String!, append: Boolean) Creates a file output stream to write to the file with the specified name.

Public methods
open Unit	close() Closes this file output stream and releases any system resources associated with this stream.
open FileChannel!	getChannel() Returns the unique FileChannel object associated with this file output stream.
FileDescriptor!	getFD() Returns the file descriptor associated with this stream.
open Unit	write(b: ByteArray!) Writes b.length bytes from the specified byte array to this file output stream.
open Unit	write(b: ByteArray!, off: Int, len: Int) Writes len bytes from the specified byte array starting at offset off to this file output stream.
open Unit	write(b: Int) Writes the specified byte to this file output stream.

Protected methods
open Unit	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 functions

From class OutputStream Unit flush() Flushes this output stream and forces any buffered output bytes to be written out. The general contract of flush is 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 flush method of OutputStream does nothing. OutputStream! nullOutputStream() Returns a new OutputStream which discards all bytes. The returned stream is initially open. The stream is closed by calling the close() method. Subsequent calls to close() have no effect. While the stream is open, the write(int), write(byte[]), and write(byte[], int, int) methods do nothing. After the stream has been closed, these methods all throw IOException. The flush() method does nothing.

Public constructors

FileOutputStream

Added in API level 1

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.

Exceptions
java.io.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
java.lang.SecurityException	if a security manager exists and its checkWrite method denies write access to the file.

See Also

• java.io.File#getPath()
• java.lang.SecurityException
• java.lang.SecurityManager#checkWrite(java.lang.String)

FileOutputStream

Added in API level 1

FileOutputStream(
    file: File!, 
    append: Boolean)

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

Exceptions
java.io.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
java.lang.SecurityException	if a security manager exists and its checkWrite method denies write access to the file.

See Also

• java.io.File#getPath()
• java.lang.SecurityException
• java.lang.SecurityManager#checkWrite(java.lang.String)

FileOutputStream

Added in API level 1

FileOutputStream(fdObj: FileDescriptor!)

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.

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

Exceptions
java.lang.SecurityException	if a security manager exists and its checkWrite method denies write access to the file descriptor

See Also

• java.lang.SecurityManager#checkWrite(java.io.FileDescriptor)

FileOutputStream

Added in API level 1

FileOutputStream(name: String!)

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.

Parameters
name	String!: the system-dependent filename

Exceptions
java.io.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
java.lang.SecurityException	if a security manager exists and its checkWrite method denies write access to the file.

See Also

• java.lang.SecurityManager#checkWrite(java.lang.String)

FileOutputStream

Added in API level 1

FileOutputStream(
    name: String!, 
    append: Boolean)

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

Exceptions
java.io.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.
java.lang.SecurityException	if a security manager exists and its checkWrite method denies write access to the file.

See Also

• java.lang.SecurityManager#checkWrite(java.lang.String)

Public methods

close

Added in API level 1

open fun close(): Unit

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.

Exceptions
java.lang.Exception	if this resource cannot be closed
java.io.IOException	if an I/O error occurs.

getChannel

Added in API level 1

open fun getChannel(): FileChannel!

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.

Return
FileChannel!	the file channel associated with this file output stream

getFD

Added in API level 1

fun getFD(): FileDescriptor!

Returns the file descriptor associated with this stream.

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

Exceptions
java.io.IOException	if an I/O error occurs.

See Also

• java.io.FileDescriptor

write

Added in API level 1

open fun write(b: ByteArray!): Unit

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

Parameters
b	ByteArray!: the data.

Exceptions
java.io.IOException	if an I/O error occurs.

write

Added in API level 1

open fun write(
    b: ByteArray!, 
    off: Int, 
    len: Int
): Unit

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

Parameters
b	ByteArray!: the data.
off	Int: the start offset in the data.
len	Int: the number of bytes to write.

Exceptions
java.io.IOException	if an I/O error occurs.

write

Added in API level 1

open fun write(b: Int): Unit

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

Parameters
b	Int: the byte to be written.

Exceptions
java.io.IOException	if an I/O error occurs.

Protected methods

finalize

Added in API level 1

protected open fun finalize(): Unit

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.

Exceptions
java.lang.Throwable	the Exception raised by this method
java.io.IOException	if an I/O error occurs.

See Also