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 1456969 2013-03-15 14:37:04Z markt $

Constructor Summary

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

Method Summary

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

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, or -1 if > Integer.MAX_VALUE

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

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.

The buffer size is given by DEFAULT_BUFFER_SIZE.

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:

1.3