Package 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 $ Code copied from apache commons io source. Changes made (mostly removal of methods) by Per Wendel.

  • Field Details

    • LINE_SEPARATOR

      public static final String LINE_SEPARATOR
      The system line separator string.

    • DEFAULT_BUFFER_SIZE

      private static final int DEFAULT_BUFFER_SIZE
      The default buffer size to use.
      See Also:

  • Constructor Details

    • IOUtils

      private IOUtils()

  • Method Details

    • 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

    • toByteArray

      public static byte[] toByteArray(InputStream input) throws IOException
      Get the contents of an InputStream as a ByteArray

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

      Parameters:
      input - the InputStream to read from
      Returns:
      the byte array
      Throws:
      NullPointerException - if the input is null
      IOException - if an I/O error occurs

    • copy

      public static int copy(InputStream input, OutputStream output) throws IOException
      Copies 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:
      Commons IO 1.1

    • copyLarge

      public static long copyLarge(InputStream input, OutputStream output) throws IOException
      Copies bytes from a large (over 2GB) InputStream to an OutputStream.

      This method uses the provided buffer, 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 2.2

    • 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