Java compact1, compact2, compact3 java.io Class FileOutputStream（JDK8）

Constructor Detail

• FileOutputStream

  public FileOutputStream(String name)
                   throws FileNotFoundException

  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 - 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

  public FileOutputStream(String name,
                          boolean append)
                   throws FileNotFoundException

  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 - 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 checkWrite method denies write access to the file.

  Since:

  JDK1.1

  See Also:

  SecurityManager.checkWrite(java.lang.String)

• FileOutputStream

  public FileOutputStream(File file)
                   throws FileNotFoundException

  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 - 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:

  File.getPath(), SecurityException, SecurityManager.checkWrite(java.lang.String)

• FileOutputStream

  public FileOutputStream(File file,
                          boolean append)
                   throws FileNotFoundException

  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 - 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 checkWrite method denies write access to the file.

  Since:

  1.4

  See Also:

  File.getPath(), SecurityException, SecurityManager.checkWrite(java.lang.String)

• FileOutputStream

  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.

  Parameters:

  fdObj - 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)

Method Detail

• write

  public void write(int b)
             throws IOException

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

  Specified by:

  write in class OutputStream

  Parameters:

  b - the byte to be written.

  Throws:

  IOException - if an I/O error occurs.

• write

  public void write(byte[] b)
             throws IOException

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

  Overrides:

  write in class OutputStream

  Parameters:

  b - the data.

  Throws:

  IOException - if an I/O error occurs.

  See Also:

  OutputStream.write(byte[], int, int)

• write

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

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

  Overrides:

  write in 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.

• close

  public void close()
             throws IOException

  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.

  Specified by:

  close in interface Closeable

  Specified by:

  close in interface AutoCloseable

  Overrides:

  close in class OutputStream

  Throws:

  IOException - if an I/O error occurs.

• getFD

  public final FileDescriptor getFD()
                             throws IOException

  Returns the file descriptor associated with this stream.

  Returns:

  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

• getChannel

  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:

  the file channel associated with this file output stream

  Since:

  1.4

• finalize

  protected void finalize()
                   throws IOException

  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.

  Overrides:

  finalize in class Object

  Throws:

  IOException - if an I/O error occurs.

  See Also:

  FileInputStream.close()