## org.apache.hadoop.io
Class IOUtils

    java.lang.Object
      org.apache.hadoop.io.IOUtils

    public class IOUtils

extends Object

An utility class for I/O related functionality.

Nested Class Summary
`static class` `IOUtils.NullOutputStream` /dev/null of OutputStreams.

Constructor Summary
`IOUtils()`

Method Summary
`static void` `cleanup(org.apache.commons.logging.Log log, Closeable... closeables)` Close the Closeable objects and ignore any `IOException` or null pointers.
`static void` `closeSocket(Socket sock)` Closes the socket ignoring `IOException`
`static void` `closeStream(Closeable stream)` Closes the stream ignoring `IOException`.
`static void` `copyBytes(InputStream in, OutputStream out, Configuration conf)` Copies from one stream to another.
`static void` `copyBytes(InputStream in, OutputStream out, Configuration conf, boolean close)` Copies from one stream to another.
`static void` `copyBytes(InputStream in, OutputStream out, int buffSize)` Copies from one stream to another.
`static void` `copyBytes(InputStream in, OutputStream out, int buffSize, boolean close)` Copies from one stream to another.
`static void` `copyBytes(InputStream in, OutputStream out, long length, int bufferSize, boolean close)` Copies the specified length of bytes from in to out.
`static void` `readFileChannelFully(FileChannel fileChannel, byte[] buf, int off, int len)` Reads len bytes in a loop using the channel of the stream
`static void` `readFully(InputStream in, byte[] buf, int off, int len)` Reads len bytes in a loop.
`static void` `skipFully(InputStream in, long len)` Similar to readFully().
`static int` `wrappedReadForCompressedData(InputStream is, byte[] buf, int off, int len)` Utility wrapper for reading from `InputStream`.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### IOUtils

    public IOUtils()

Method Detail

### copyBytes

    public static void copyBytes(InputStream in,
                                 OutputStream out,
                                 int buffSize,
                                 boolean close)
                          throws IOException

  Copies from one stream to another.

  Parameters:
    `in` - InputStrem to read from
    `out` - OutputStream to write to
    `buffSize` - the size of the buffer
    `close` - whether or not close the InputStream and OutputStream at the end. The streams are closed in the finally clause.
  Throws:
    `IOException`

### copyBytes

    public static void copyBytes(InputStream in,
                                 OutputStream out,
                                 int buffSize)
                          throws IOException

  Copies from one stream to another.

  Parameters:
    `in` - InputStrem to read from
    `out` - OutputStream to write to
    `buffSize` - the size of the buffer
  Throws:
    `IOException`

### copyBytes

    public static void copyBytes(InputStream in,
                                 OutputStream out,
                                 Configuration conf)
                          throws IOException

  Copies from one stream to another. closes the input and output streams at the end.

  Parameters:
    `in` - InputStrem to read from
    `out` - OutputStream to write to
    `conf` - the Configuration object
  Throws:
    `IOException`

### copyBytes

    public static void copyBytes(InputStream in,
                                 OutputStream out,
                                 Configuration conf,
                                 boolean close)
                          throws IOException

  Copies from one stream to another.

  Parameters:
    `in` - InputStrem to read from
    `out` - OutputStream to write to
    `conf` - the Configuration object
    `close` - whether or not close the InputStream and OutputStream at the end. The streams are closed in the finally clause.
  Throws:
    `IOException`

### copyBytes

    public static void copyBytes(InputStream in,
                                 OutputStream out,
                                 long length,
                                 int bufferSize,
                                 boolean close)
                          throws IOException

  Copies the specified length of bytes from in to out.

  Parameters:
    `in` - InputStream to read from
    `out` - OutputStream to write to
    `length` - number of bytes to copy
    `bufferSize` - the size of the buffer
    `close` - whether to close the streams
  Throws:
    `IOException` - if bytes can not be read or written

### wrappedReadForCompressedData

    public static int wrappedReadForCompressedData(InputStream is,
                                                   byte[] buf,
                                                   int off,
                                                   int len)
                                            throws IOException

  Utility wrapper for reading from `InputStream`. It catches any errors thrown by the underlying stream (either IO or decompression-related), and re-throws as an IOException.

  Parameters:
    `is` - - InputStream to be read from
    `buf` - - buffer the data is read into
    `off` - - offset within buf
    `len` - - amount of data to be read
  Returns:
    number of bytes read
  Throws:
    `IOException`

### readFully

    public static void readFully(InputStream in,
                                 byte[] buf,
                                 int off,
                                 int len)
                          throws IOException

  Reads len bytes in a loop.

  Parameters:
    `in` - The InputStream to read from
    `buf` - The buffer to fill
    `off` - offset from the buffer
    `len` - the length of bytes to read
  Throws:
    `IOException` - if it could not read requested number of bytes for any reason (including EOF)

### readFileChannelFully

    public static void readFileChannelFully(FileChannel fileChannel,
                                            byte[] buf,
                                            int off,
                                            int len)
                                     throws IOException

  Reads len bytes in a loop using the channel of the stream

  Parameters:
    `fileChannel` - a FileChannel to read len bytes into buf
    `buf` - The buffer to fill
    `off` - offset from the buffer
    `len` - the length of bytes to read
  Throws:
    `IOException` - if it could not read requested number of bytes for any reason (including EOF)

### skipFully

    public static void skipFully(InputStream in,
                                 long len)
                          throws IOException

  Similar to readFully(). Skips bytes in a loop.

  Parameters:
    `in` - The InputStream to skip bytes from
    `len` - number of bytes to skip.
  Throws:
    `IOException` - if it could not skip requested number of bytes for any reason (including EOF)

### cleanup

    public static void cleanup(org.apache.commons.logging.Log log,
                               Closeable... closeables)

  Close the Closeable objects and ignore any `IOException` or null pointers. Must only be used for cleanup in exception handlers.

  Parameters:
    `log` - the log to record problems to at debug level. Can be null.
    `closeables` - the objects to close

### closeStream

    public static void closeStream(Closeable stream)

  Closes the stream ignoring `IOException`. Must only be called in cleaning up from exception handlers.

  Parameters:
    `stream` - the Stream to close

### closeSocket

    public static void closeSocket(Socket sock)

  Closes the socket ignoring `IOException`

  Parameters:
    `sock` - the Socket to close

Copyright © 2009 The Apache Software Foundation