Package spark.utils

Class IOUtils


  • public final class IOUtils
    extends java.lang.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 Summary

      Fields 
      Modifier and Type Field Description
      private static int DEFAULT_BUFFER_SIZE
      The default buffer size to use.
      static java.lang.String LINE_SEPARATOR
      The system line separator string.
    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      private IOUtils()  
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static int copy​(java.io.InputStream input, java.io.OutputStream output)
      Copies 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 int copy​(java.io.Reader input, java.io.Writer output)
      Copy chars from a Reader to a Writer.
      static long copyLarge​(java.io.InputStream input, java.io.OutputStream output)
      Copies bytes from a large (over 2GB) InputStream to an OutputStream.
      static long copyLarge​(java.io.Reader input, java.io.Writer output)
      Copy chars from a large (over 2GB) Reader to a Writer.
      static byte[] toByteArray​(java.io.InputStream input)
      Get the contents of an InputStream as a ByteArray
      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.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

      • LINE_SEPARATOR

        public static final java.lang.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:
        Constant Field Values
    • Constructor Detail

      • IOUtils

        private IOUtils()
    • Method Detail

      • 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
      • toByteArray

        public static byte[] toByteArray​(java.io.InputStream input)
                                  throws java.io.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:
        java.lang.NullPointerException - if the input is null
        java.io.IOException - if an I/O error occurs
      • copy

        public static int copy​(java.io.InputStream input,
                               java.io.OutputStream output)
                        throws java.io.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:
        java.lang.NullPointerException - if the input or output is null
        java.io.IOException - if an I/O error occurs
        Since:
        Commons IO 1.1
      • copyLarge

        public static long copyLarge​(java.io.InputStream input,
                                     java.io.OutputStream output)
                              throws java.io.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:
        java.lang.NullPointerException - if the input or output is null
        java.io.IOException - if an I/O error occurs
        Since:
        Commons IO 2.2
      • 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:
        Commons IO 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.

        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:
        java.lang.NullPointerException - if the input or output is null
        java.io.IOException - if an I/O error occurs
        java.lang.ArithmeticException - if the character count is too large
        Since:
        Commons IO 1.1
      • copyLarge

        public static long copyLarge​(java.io.Reader input,
                                     java.io.Writer output)
                              throws java.io.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:
        java.lang.NullPointerException - if the input or output is null
        java.io.IOException - if an I/O error occurs
        Since:
        Commons IO 1.3