org.apache.tomcat.util.http.fileupload
Class IOUtils

java.lang.Object
  org.apache.tomcat.util.http.fileupload.IOUtils

public class IOUtils
extends Object

General IO stream manipulation utilities.

This class provides static utility methods for input/output operations.

• closeQuietly - these methods close a stream ignoring nulls and exceptions
• toXxx/read - these methods read data from a stream
• write - these methods write data to a stream
• copy - these methods copy all the data from one stream to another
• contentEquals - these methods compare the content of two streams

The byte-to-char methods and char-to-byte methods involve a conversion step. Two methods are provided in each case, one that uses the platform default encoding and the other which allows you to specify an encoding. You are encouraged to always specify an encoding because relying on the platform default can lead to unexpected results, for example when moving from development to production.

All the methods in this class that read a stream are buffered internally. This means that there is no cause to use a BufferedInputStream or BufferedReader. The default buffer size of 4K has been shown to be efficient in tests.

Wherever possible, the methods in this class do not flush or close the stream. This is to avoid making non-portable assumptions about the streams' origin and further use. Thus the caller is still responsible for closing streams after use.

Origin of code: Excalibur.

Version:

$Id: IOUtils.java 992409 2010-09-03 18:35:59Z markt $

Author:

Peter Donald, Jeff Turner, Matthew Hawthorne, Stephen Colebourne, Gareth Davis, Ian Springer, Niall Pemberton, Sandy McArthur

Constructor Summary

IOUtils()
Instances should NOT be constructed in standard programming.

Method Summary

static void	closeQuietly(InputStream input) Unconditionally close an InputStream.
static int	copy(InputStream input, OutputStream output) Copy bytes from an InputStream to an OutputStream.
static long	copyLarge(InputStream input, OutputStream output) Copy bytes from a large (over 2GB) InputStream to an OutputStream.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

IOUtils

public IOUtils()

Instances should NOT be constructed in standard programming.

Method Detail

closeQuietly

public static void closeQuietly(InputStream input)

Unconditionally close an InputStream.

Equivalent to InputStream.close(), except any exceptions will be ignored. This is typically used in finally blocks.

Parameters:

input - the InputStream to close, may be null or already closed

copy

public static int copy(InputStream input,
                       OutputStream output)
                throws IOException

Copy bytes from an InputStream to an OutputStream.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Large streams (over 2GB) will return a bytes copied value of -1 after the copy has completed since the correct number of bytes cannot be returned as an int. For large streams use the copyLarge(InputStream, OutputStream) method.

Parameters:

input - the InputStream to read from

output - the OutputStream to write to

Returns:

the number of bytes copied

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

ArithmeticException - if the byte count is too large

Since:

Commons IO 1.1

copyLarge

public static long copyLarge(InputStream input,
                             OutputStream output)
                      throws IOException

Copy bytes from a large (over 2GB) InputStream to an OutputStream.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - the InputStream to read from

output - the OutputStream to write to

Returns:

the number of bytes copied

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.3