Package java.io

Class ByteArrayOutputStream

  • All Implemented Interfaces:
    Closeable, Flushable, AutoCloseable
    public class ByteArrayOutputStream
extends OutputStream
    This class implements an output stream in which the data is written into a byte array. The buffer automatically grows as data is written to it. The data can be retrieved using toByteArray() and toString().

    Closing a ByteArrayOutputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.

    • Constructor Summary

      Constructors 
      Constructor Description
      ByteArrayOutputStream()
      Creates a new byte array output stream.
      ByteArrayOutputStream​(int size)
      Creates a new byte array output stream, with a buffer capacity of the specified size, in bytes.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void close()
      Closing a ByteArrayOutputStream has no effect.
      void reset()
      Resets the count field of this byte array output stream to zero, so that all currently accumulated output in the output stream is discarded.
      int size()
      Returns the current size of the buffer.
      byte[] toByteArray()
      Creates a newly allocated byte array.
      String toString()
      Converts the buffer's contents into a string decoding bytes using the platform's default character set.
      void write​(byte[] b, int off, int len)
      Writes len bytes from the specified byte array starting at offset off to this byte array output stream.
      void write​(int b)
      Writes the specified byte to this byte array output stream.
      void writeTo​(OutputStream out)
      Writes the complete contents of this byte array output stream to the specified output stream argument, as if by calling the output stream's write method using out.write(buf, 0, count).

    • Constructor Detail

      • ByteArrayOutputStream

        public ByteArrayOutputStream()
        Creates a new byte array output stream. The buffer capacity is initially 32 bytes, though its size increases if necessary.

      • ByteArrayOutputStream

        public ByteArrayOutputStream​(int size)
        Creates a new byte array output stream, with a buffer capacity of the specified size, in bytes.
        Parameters:
        size - the initial size.
        Throws:
        IllegalArgumentException - if size is negative.

    • Method Detail

      • close

        public void close()
           throws IOException
        Closing a ByteArrayOutputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.
        Specified by:
        close in interface AutoCloseable
        Specified by:
        close in interface Closeable
        Overrides:
        close in class OutputStream
        Throws:
        IOException - if an I/O error occurs.

      • reset

        public void reset()
        Resets the count field of this byte array output stream to zero, so that all currently accumulated output in the output stream is discarded. The output stream can be used again, reusing the already allocated buffer space.
        See Also:
        java.io.ByteArrayInputStream#count

      • size

        public int size()
        Returns the current size of the buffer.
        Returns:
        the value of the count field, which is the number of valid bytes in this output stream.
        See Also:
        java.io.ByteArrayOutputStream#count

      • toByteArray

        public byte[] toByteArray()
        Creates a newly allocated byte array. Its size is the current size of this output stream and the valid contents of the buffer have been copied into it.
        Returns:
        the current contents of this output stream, as a byte array.
        See Also:
        size()

      • toString

        public String toString()
        Converts the buffer's contents into a string decoding bytes using the platform's default character set. The length of the new String is a function of the character set, and hence may not be equal to the size of the buffer.
        Overrides:
        toString in class Object
        Returns:
        String decoded from the buffer's contents.

      • write

        public void write​(byte[] b,
                  int off,
                  int len)
        Writes len bytes from the specified byte array starting at offset off to this byte array output stream.
        Overrides:
        write in class OutputStream
        Parameters:
        b - the data.
        off - the start offset in the data.
        len - the number of bytes to write.

      • write

        public void write​(int b)
        Writes the specified byte to this byte array output stream.
        Specified by:
        write in class OutputStream
        Parameters:
        b - the byte to be written.

      • writeTo

        public void writeTo​(OutputStream out)
             throws IOException
        Writes the complete contents of this byte array output stream to the specified output stream argument, as if by calling the output stream's write method using out.write(buf, 0, count).
        Parameters:
        out - the output stream to which to write the data.
        Throws:
        IOException - if an I/O error occurs.