spark.utils

Class IOUtils

java.lang.Object

spark.utils.IOUtils

public final 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 481854 2006-12-03 18:30:07Z scolebourne $

Author:

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

Field Summary

Fields

Modifier and Type	Field and Description
static char	DIR_SEPARATOR The system directory separator character.
static char	DIR_SEPARATOR_UNIX The Unix directory separator character.
static char	DIR_SEPARATOR_WINDOWS The Windows directory separator character.
static String	LINE_SEPARATOR The system line separator string.
static String	LINE_SEPARATOR_UNIX The Unix line separator string.
static String	LINE_SEPARATOR_WINDOWS The Windows line separator string.

Method Summary

Methods

Modifier and Type	Method and Description
static void	copy(InputStream input, Writer output) Copy bytes from an InputStream to chars on a Writer using the default character encoding of the platform.
static int	copy(Reader input, Writer output) Copy chars from a Reader to a Writer.
static long	copyLarge(Reader input, Writer output) Copy chars from a large (over 2GB) Reader to a Writer.
static String	toString(InputStream input) Get the contents of an InputStream as a String using the default character encoding of the platform.

Methods inherited from class java.lang.Object

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

Field Detail

DIR_SEPARATOR_UNIX

public static final char DIR_SEPARATOR_UNIX

The Unix directory separator character.

See Also:

Constant Field Values

DIR_SEPARATOR_WINDOWS

public static final char DIR_SEPARATOR_WINDOWS

The Windows directory separator character.

See Also:

Constant Field Values

DIR_SEPARATOR

public static final char DIR_SEPARATOR

The system directory separator character.

LINE_SEPARATOR_UNIX

public static final String LINE_SEPARATOR_UNIX

The Unix line separator string.

See Also:

Constant Field Values

LINE_SEPARATOR_WINDOWS

public static final String LINE_SEPARATOR_WINDOWS

The Windows line separator string.

See Also:

Constant Field Values

LINE_SEPARATOR

public static final String LINE_SEPARATOR

The system line separator string.

Method Detail

toString

public static String toString(InputStream input)
                       throws 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:

NullPointerException - if the input is null

IOException - if an I/O error occurs

copy

public static void copy(InputStream input,
        Writer output)
                 throws 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:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.1

copy

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

Copy chars from a Reader to a Writer.

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

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

Parameters:

input - the Reader to read from

output - the Writer to write to

Returns:

the number of characters copied

Throws:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

ArithmeticException - if the character count is too large

Since:

Commons IO 1.1

copyLarge

public static long copyLarge(Reader input,
             Writer output)
                      throws IOException

Copy chars from a large (over 2GB) 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:

NullPointerException - if the input or output is null

IOException - if an I/O error occurs

Since:

Commons IO 1.3