org.apache.wicket.util.io
Class IOUtils

java.lang.Object
  org.apache.wicket.util.io.IOUtils

public final class IOUtils
extends java.lang.Object

General IO Stream manipulation.

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

• closeQuietly - these method closes any kind of closeable resource, e.g. an input/output stream or reader/writer ignoring nulls and exceptions
• toXxx - 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 show 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: Apache Avalon (Excalibur)

Version:

CVS $Revision$ $Date$

Author:

Peter Donald, Jeff Turner, Matthew Hawthorne, Stephen Colebourne, Gareth Davis

Constructor Summary

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

Method Summary

static void	close(java.io.Closeable closeable) Closes a closeable.
static void	closeQuietly(java.io.Closeable closeable) Unconditionally close a Closeable.
static boolean	contentEquals(java.io.InputStream input1, java.io.InputStream input2) Compare the contents of two Streams to determine if they are equal or not.
static boolean	contentEquals(java.io.Reader input1, java.io.Reader input2) Compare the contents of two Readers to determine if they are equal or not.
static int	copy(java.io.InputStream input, java.io.OutputStream output) Copy bytes from an InputStream to an OutputStream.
static void	copy(java.io.InputStream input, java.io.Writer output) Copy bytes from an InputStream to chars on a Writer using the default character encoding of the platform.
static void	copy(java.io.InputStream input, java.io.Writer output, java.lang.String encoding) Copy bytes from an InputStream to chars on a Writer using the specified character encoding.
static void	copy(java.io.Reader input, java.io.OutputStream output) Copy chars from a Reader to bytes on an OutputStream using the default character encoding of the platform, and calling flush.
static void	copy(java.io.Reader input, java.io.OutputStream output, java.lang.String encoding) Copy chars from a Reader to bytes on an OutputStream using the specified character encoding, and calling flush.
static int	copy(java.io.Reader input, java.io.Writer output) Copy chars from a Reader to a Writer.
static byte[]	toByteArray(java.io.InputStream input) Get the contents of an InputStream as a byte[].
static byte[]	toByteArray(java.io.Reader input) Get the contents of a Reader as a byte[] using the default character encoding of the platform.
static byte[]	toByteArray(java.io.Reader input, java.lang.String encoding) Get the contents of a Reader as a byte[] using the specified character encoding.
static char[]	toCharArray(java.io.InputStream is) Get the contents of an InputStream as a character array using the default character encoding of the platform.
static char[]	toCharArray(java.io.InputStream is, java.lang.String encoding) Get the contents of an InputStream as a character array using the specified character encoding.
static char[]	toCharArray(java.io.Reader input) Get the contents of a Reader as a character array.
static java.lang.String	toString(java.io.InputStream input) Get the contents of an InputStream as a String using the default character encoding of the platform.
static java.lang.String	toString(java.io.InputStream input, java.lang.String encoding) Get the contents of an InputStream as a String using the specified character encoding.
static java.lang.String	toString(java.io.Reader input) Get the contents of a Reader as a String.
static void	write(byte[] data, java.io.OutputStream output) Writes bytes from a byte[] to an OutputStream.
static void	write(byte[] data, java.io.Writer output) Writes bytes from a byte[] to chars on a Writer using the default character encoding of the platform.
static void	write(byte[] data, java.io.Writer output, java.lang.String encoding) Writes bytes from a byte[] to chars on a Writer using the specified character encoding.
static void	write(char[] data, java.io.OutputStream output) Writes chars from a char[] to bytes on an OutputStream.
static void	write(char[] data, java.io.OutputStream output, java.lang.String encoding) Writes chars from a char[] to bytes on an OutputStream using the specified character encoding.
static void	write(char[] data, java.io.Writer output) Writes chars from a char[] to a Writer using the default character encoding of the platform.
static void	write(java.lang.StringBuilder data, java.io.OutputStream output) Writes chars from a AppendingStringBuffer to bytes on an OutputStream using the default character encoding of the platform.
static void	write(java.lang.StringBuilder data, java.io.OutputStream output, java.lang.String encoding) Writes chars from a AppendingStringBuffer to bytes on an OutputStream using the specified character encoding.
static void	write(java.lang.StringBuilder data, java.io.Writer output) Writes chars from a AppendingStringBuffer to a Writer.
static void	write(java.lang.String data, java.io.OutputStream output) Writes chars from a String to bytes on an OutputStream using the default character encoding of the platform.
static void	write(java.lang.String data, java.io.OutputStream output, java.lang.String encoding) Writes chars from a String to bytes on an OutputStream using the specified character encoding.
static void	write(java.lang.String data, java.io.Writer output) Writes chars from a String to a Writer.

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

close

public static void close(java.io.Closeable closeable)
                  throws java.io.IOException

Closes a closeable. Guards against null closables.

Parameters:

closeable - closeable to close

Throws:

java.io.IOException - when close fails

closeQuietly

public static void closeQuietly(java.io.Closeable closeable)

Unconditionally close a Closeable.

closeables can be input or output streams, reader, writers, and much more. Equivalent to Closeable.close(), except any exceptions will be ignored. This is typically used in finally blocks.

Parameters:

closeable - the Closeable to close, may be null or already closed

toByteArray

public static byte[] toByteArray(java.io.InputStream input)
                          throws java.io.IOException

Get the contents of an InputStream as a byte[].

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

Parameters:

input - the InputStream to read from

Returns:

the requested byte array

Throws:

java.lang.NullPointerException - if the input is null

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

toByteArray

public static byte[] toByteArray(java.io.Reader input)
                          throws java.io.IOException

Get the contents of a Reader as a byte[] using the default character encoding of the platform.

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

Parameters:

input - the Reader to read from

Returns:

the requested byte array

Throws:

java.lang.NullPointerException - if the input is null

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

toByteArray

public static byte[] toByteArray(java.io.Reader input,
                                 java.lang.String encoding)
                          throws java.io.IOException

Get the contents of a Reader as a byte[] using the specified character encoding.

Character encoding names can be found at IANA.

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

Parameters:

input - the Reader to read from

encoding - the encoding to use, null means platform default

Returns:

the requested byte array

Throws:

java.lang.NullPointerException - if the input is null

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

Since:

1.1

toCharArray

public static char[] toCharArray(java.io.InputStream is)
                          throws java.io.IOException

Get the contents of an InputStream as a character array using the default character encoding of the platform.

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

Parameters:

is - the InputStream to read from

Returns:

the requested character array

Throws:

java.lang.NullPointerException - if the input is null

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

toCharArray

public static char[] toCharArray(java.io.InputStream is,
                                 java.lang.String encoding)
                          throws java.io.IOException

Get the contents of an InputStream as a character array using the specified character encoding.

Character encoding names can be found at IANA.

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

Parameters:

is - the InputStream to read from

encoding - the encoding to use, null means platform default

Returns:

the requested character array

Throws:

java.lang.NullPointerException - if the input is null

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

toCharArray

public static char[] toCharArray(java.io.Reader input)
                          throws java.io.IOException

Get the contents of a Reader as a character array.

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

Parameters:

input - the Reader to read from

Returns:

the requested character array

Throws:

java.lang.NullPointerException - if the input is null

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

toString

public static java.lang.String toString(java.io.InputStream input)
                                 throws java.io.IOException

Get the contents of an InputStream as a String using the default character encoding of the platform.

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

Parameters:

input - the InputStream to read from

Returns:

the requested String

Throws:

java.lang.NullPointerException - if the input is null

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

toString

public static java.lang.String toString(java.io.InputStream input,
                                        java.lang.String encoding)
                                 throws java.io.IOException

Get the contents of an InputStream as a String using the specified character encoding.

Character encoding names can be found at IANA.

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

Parameters:

input - the InputStream to read from

encoding - the encoding to use, null means platform default

Returns:

the requested String

Throws:

java.lang.NullPointerException - if the input is null

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

toString

public static java.lang.String toString(java.io.Reader input)
                                 throws java.io.IOException

Get the contents of a Reader as a String.

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

Parameters:

input - the Reader to read from

Returns:

the requested String

Throws:

java.lang.NullPointerException - if the input is null

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

write

public static void write(byte[] data,
                         java.io.OutputStream output)
                  throws java.io.IOException

Writes bytes from a byte[] to an OutputStream.

Parameters:

data - the byte array to write, do not modify during output, null ignored

output - the OutputStream to write to

Throws:

java.lang.NullPointerException - if output is null

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

Since:

1.1

write

public static void write(byte[] data,
                         java.io.Writer output)
                  throws java.io.IOException

Writes bytes from a byte[] to chars on a Writer using the default character encoding of the platform.

This method uses String.String(byte[]).

Parameters:

data - the byte array to write, do not modify during output, null ignored

output - the Writer to write to

Throws:

java.lang.NullPointerException - if output is null

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

Since:

1.1

write

public static void write(byte[] data,
                         java.io.Writer output,
                         java.lang.String encoding)
                  throws java.io.IOException

Writes bytes from a byte[] to chars on a Writer using the specified character encoding.

Character encoding names can be found at IANA.

This method uses String.String(byte[], String).

Parameters:

data - the byte array to write, do not modify during output, null ignored

output - the Writer to write to

encoding - the encoding to use, null means platform default

Throws:

java.lang.NullPointerException - if output is null

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

Since:

1.1

write

public static void write(char[] data,
                         java.io.Writer output)
                  throws java.io.IOException

Writes chars from a char[] to a Writer using the default character encoding of the platform.

Parameters:

data - the char array to write, do not modify during output, null ignored

output - the Writer to write to

Throws:

java.lang.NullPointerException - if output is null

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

Since:

1.1

write

public static void write(char[] data,
                         java.io.OutputStream output)
                  throws java.io.IOException

Writes chars from a char[] to bytes on an OutputStream.

This method uses String.String(char[]) and String.getBytes().

Parameters:

data - the char array to write, do not modify during output, null ignored

output - the OutputStream to write to

Throws:

java.lang.NullPointerException - if output is null

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

Since:

1.1

write

public static void write(char[] data,
                         java.io.OutputStream output,
                         java.lang.String encoding)
                  throws java.io.IOException

Writes chars from a char[] to bytes on an OutputStream using the specified character encoding.

Character encoding names can be found at IANA.

This method uses String.String(char[]) and String.getBytes(String).

Parameters:

data - the char array to write, do not modify during output, null ignored

output - the OutputStream to write to

encoding - the encoding to use, null means platform default

Throws:

java.lang.NullPointerException - if output is null

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

Since:

1.1

write

public static void write(java.lang.String data,
                         java.io.Writer output)
                  throws java.io.IOException

Writes chars from a String to a Writer.

Parameters:

data - the String to write, null ignored

output - the Writer to write to

Throws:

java.lang.NullPointerException - if output is null

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

Since:

1.1

write

public static void write(java.lang.String data,
                         java.io.OutputStream output)
                  throws java.io.IOException

Writes chars from a String to bytes on an OutputStream using the default character encoding of the platform.

This method uses String.getBytes().

Parameters:

data - the String to write, null ignored

output - the OutputStream to write to

Throws:

java.lang.NullPointerException - if output is null

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

Since:

1.1

write

public static void write(java.lang.String data,
                         java.io.OutputStream output,
                         java.lang.String encoding)
                  throws java.io.IOException

Writes chars from a String to bytes on an OutputStream using the specified character encoding.

Character encoding names can be found at IANA.

This method uses String.getBytes(String).

Parameters:

data - the String to write, null ignored

output - the OutputStream to write to

encoding - the encoding to use, null means platform default

Throws:

java.lang.NullPointerException - if output is null

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

Since:

1.1

write

public static void write(java.lang.StringBuilder data,
                         java.io.Writer output)
                  throws java.io.IOException

Writes chars from a AppendingStringBuffer to a Writer.

Parameters:

data - the AppendingStringBuffer to write, null ignored

output - the Writer to write to

Throws:

java.lang.NullPointerException - if output is null

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

Since:

1.1

write

public static void write(java.lang.StringBuilder data,
                         java.io.OutputStream output)
                  throws java.io.IOException

Writes chars from a AppendingStringBuffer to bytes on an OutputStream using the default character encoding of the platform.

This method uses String.getBytes().

Parameters:

data - the AppendingStringBuffer to write, null ignored

output - the OutputStream to write to

Throws:

java.lang.NullPointerException - if output is null

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

Since:

1.1

write

public static void write(java.lang.StringBuilder data,
                         java.io.OutputStream output,
                         java.lang.String encoding)
                  throws java.io.IOException

Writes chars from a AppendingStringBuffer to bytes on an OutputStream using the specified character encoding.

Character encoding names can be found at IANA.

This method uses String.getBytes(String).

Parameters:

data - the AppendingStringBuffer to write, null ignored

output - the OutputStream to write to

encoding - the encoding to use, null means platform default

Throws:

java.lang.NullPointerException - if output is null

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

Since:

1.1

copy

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

Copy bytes from an 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:

java.lang.NullPointerException - if the input or output is null

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

Since:

1.1

copy

public static void copy(java.io.InputStream input,
                        java.io.Writer output)
                 throws java.io.IOException

Copy bytes from an InputStream to chars on a Writer using the default character encoding of the platform.

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

This method uses InputStreamReader.

Parameters:

input - the InputStream to read from

output - the Writer to write to

Throws:

java.lang.NullPointerException - if the input or output is null

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

Since:

1.1

copy

public static void copy(java.io.InputStream input,
                        java.io.Writer output,
                        java.lang.String encoding)
                 throws java.io.IOException

Copy bytes from an InputStream to chars on a Writer using the specified character encoding.

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

Character encoding names can be found at IANA.

This method uses InputStreamReader.

Parameters:

input - the InputStream to read from

output - the Writer to write to

encoding - the encoding to use, null means platform default

Throws:

java.lang.NullPointerException - if the input or output is null

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

Since:

1.1

copy

public static int copy(java.io.Reader input,
                       java.io.Writer output)
                throws java.io.IOException

Copy chars from a Reader to a Writer.

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

Parameters:

input - the Reader to read from

output - the Writer to write to

Returns:

the number of characters copied

Throws:

java.lang.NullPointerException - if the input or output is null

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

Since:

1.1

copy

public static void copy(java.io.Reader input,
                        java.io.OutputStream output)
                 throws java.io.IOException

Copy chars from a Reader to bytes on an OutputStream using the default character encoding of the platform, and calling flush.

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

Due to the implementation of OutputStreamWriter, this method performs a flush.

This method uses OutputStreamWriter.

Parameters:

input - the Reader to read from

output - the OutputStream to write to

Throws:

java.lang.NullPointerException - if the input or output is null

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

Since:

1.1

copy

public static void copy(java.io.Reader input,
                        java.io.OutputStream output,
                        java.lang.String encoding)
                 throws java.io.IOException

Copy chars from a Reader to bytes on an OutputStream using the specified character encoding, and calling flush.

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

Character encoding names can be found at IANA.

Due to the implementation of OutputStreamWriter, this method performs a flush.

This method uses OutputStreamWriter.

Parameters:

input - the Reader to read from

output - the OutputStream to write to

encoding - the encoding to use, null means platform default

Throws:

java.lang.NullPointerException - if the input or output is null

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

Since:

1.1

contentEquals

public static boolean contentEquals(java.io.InputStream input1,
                                    java.io.InputStream input2)
                             throws java.io.IOException

Compare the contents of two Streams to determine if they are equal or not.

This method buffers the input internally using BufferedInputStream if they are not already buffered.

Parameters:

input1 - the first stream

input2 - the second stream

Returns:

true if the content of the streams are equal or they both don't exist, false otherwise

Throws:

java.lang.NullPointerException - if either input is null

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

contentEquals

public static boolean contentEquals(java.io.Reader input1,
                                    java.io.Reader input2)
                             throws java.io.IOException

Compare the contents of two Readers to determine if they are equal or not.

This method buffers the input internally using BufferedReader if they are not already buffered.

Parameters:

input1 - the first reader

input2 - the second reader

Returns:

true if the content of the readers are equal or they both don't exist, false otherwise

Throws:

java.lang.NullPointerException - if either input is null

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

Since:

1.1