Package org.apache.wicket.util.io

Class IOUtils

java.lang.Object
org.apache.wicket.util.io.IOUtils
public final class IOUtils extends 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)

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

  • Constructor Summary

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

  • Method Summary

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

    • IOUtils

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

  • Method Details

    • close

      public static void close(Closeable closeable) throws IOException
      Closes a closeable. Guards against null closables.
      Parameters:
      closeable - closeable to close
      Throws:
      IOException - when close fails

    • closeQuietly

      public static void closeQuietly(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(InputStream input) throws 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:
      NullPointerException - if the input is null
      IOException - if an I/O error occurs

    • toByteArray

      public static byte[] toByteArray(Reader input) throws 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:
      NullPointerException - if the input is null
      IOException - if an I/O error occurs

    • toByteArray

      public static byte[] toByteArray(Reader input, String encoding) throws 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:
      NullPointerException - if the input is null
      IOException - if an I/O error occurs
      Since:
      1.1

    • toCharArray

      public static char[] toCharArray(InputStream is) throws 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:
      NullPointerException - if the input is null
      IOException - if an I/O error occurs

    • toCharArray

      public static char[] toCharArray(InputStream is, String encoding) throws 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:
      NullPointerException - if the input is null
      IOException - if an I/O error occurs

    • toCharArray

      public static char[] toCharArray(Reader input) throws 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:
      NullPointerException - if the input is null
      IOException - if an I/O error occurs

    • 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

    • toString

      public static String toString(InputStream input, String encoding) throws 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:
      NullPointerException - if the input is null
      IOException - if an I/O error occurs

    • toString

      public static String toString(Reader input) throws 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:
      NullPointerException - if the input is null
      IOException - if an I/O error occurs

    • write

      public static void write(byte[] data, OutputStream output) throws 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:
      NullPointerException - if output is null
      IOException - if an I/O error occurs
      Since:
      1.1

    • write

      public static void write(byte[] data, Writer output) throws IOException
      Writes bytes from a byte[] to chars on a Writer using the default character encoding of the platform.

      This method uses String(byte[]).

      Parameters:
      data - the byte array to write, do not modify during output, null ignored
      output - the Writer to write to
      Throws:
      NullPointerException - if output is null
      IOException - if an I/O error occurs
      Since:
      1.1

    • write

      public static void write(byte[] data, Writer output, String encoding) throws 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(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:
      NullPointerException - if output is null
      IOException - if an I/O error occurs
      Since:
      1.1

    • write

      public static void write(char[] data, Writer output) throws 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:
      NullPointerException - if output is null
      IOException - if an I/O error occurs
      Since:
      1.1

    • write

      public static void write(char[] data, OutputStream output) throws IOException
      Writes chars from a char[] to bytes on an OutputStream.

      This method uses 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:
      NullPointerException - if output is null
      IOException - if an I/O error occurs
      Since:
      1.1

    • write

      public static void write(char[] data, OutputStream output, String encoding) throws 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(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:
      NullPointerException - if output is null
      IOException - if an I/O error occurs
      Since:
      1.1

    • write

      public static void write(String data, Writer output) throws IOException
      Writes chars from a String to a Writer.
      Parameters:
      data - the String to write, null ignored
      output - the Writer to write to
      Throws:
      NullPointerException - if output is null
      IOException - if an I/O error occurs
      Since:
      1.1

    • write

      public static void write(String data, OutputStream output) throws 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:
      NullPointerException - if output is null
      IOException - if an I/O error occurs
      Since:
      1.1

    • write

      public static void write(String data, OutputStream output, String encoding) throws 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:
      NullPointerException - if output is null
      IOException - if an I/O error occurs
      Since:
      1.1

    • write

      public static void write(StringBuilder data, Writer output) throws IOException
      Writes chars from a AppendingStringBuffer to a Writer.
      Parameters:
      data - the AppendingStringBuffer to write, null ignored
      output - the Writer to write to
      Throws:
      NullPointerException - if output is null
      IOException - if an I/O error occurs
      Since:
      1.1

    • write

      public static void write(StringBuilder data, OutputStream output) throws 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:
      NullPointerException - if output is null
      IOException - if an I/O error occurs
      Since:
      1.1

    • write

      public static void write(StringBuilder data, OutputStream output, String encoding) throws 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:
      NullPointerException - if output is null
      IOException - if an I/O error occurs
      Since:
      1.1

    • 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.

      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:
      1.1

    • 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:
      1.1

    • copy

      public static void copy(InputStream input, Writer output, String encoding) throws 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:
      NullPointerException - if the input or output is null
      IOException - if an I/O error occurs
      Since:
      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.

      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:
      1.1

    • copy

      public static void copy(Reader input, OutputStream output) throws 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:
      NullPointerException - if the input or output is null
      IOException - if an I/O error occurs
      Since:
      1.1

    • copy

      public static void copy(Reader input, OutputStream output, String encoding) throws 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:
      NullPointerException - if the input or output is null
      IOException - if an I/O error occurs
      Since:
      1.1

    • contentEquals

      public static boolean contentEquals(InputStream input1, InputStream input2) throws 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:
      NullPointerException - if either input is null
      IOException - if an I/O error occurs

    • contentEquals

      public static boolean contentEquals(Reader input1, Reader input2) throws 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:
      NullPointerException - if either input is null
      IOException - if an I/O error occurs
      Since:
      1.1