J2Me学习ByteArrayOutputStream

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Copyright © 2006 Sun Microsystems, Inc. and Motorola, Inc. All rights reserved.
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java.io
Class ByteArrayOutputStream

java.lang.Object
  extended byjava.io.OutputStream
      extended byjava.io.ByteArrayOutputStream

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().

Since:
    JDK1.0, CLDC 1.0

Field Summary
protected  byte[] buf
          The buffer where data is stored.
protected  int count
          The number of valid bytes in the buffer.

Constructor Summary
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
void close()
          Closes this output stream and releases any system resources associated with this stream.
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, translating bytes into characters according to the platform's default character encoding.
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.

Methods inherited from class java.io.OutputStream
flush, write

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait


Field Detail
buf

protected byte[] buf

    The buffer where data is stored.

count

protected int count

    The number of valid bytes in the buffer.

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
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.

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.

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:
        ByteArrayInputStream.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()

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:
        count

toString

public String toString()

    Converts the buffer's contents into a string, translating bytes into characters according to the platform's default character encoding.

    Overrides:
        toString in class Object

    Returns:
        String translated from the buffer's contents.
    Since:
        JDK1.1

close

public void close()
           throws IOException

    Closes this output stream and releases any system resources associated with this stream. A closed stream cannot perform output operations and cannot be reopened.

    Overrides:
        close in class OutputStream

    Throws:
        IOException - if an I/O error occurs.

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Copyright © 2006 Sun Microsystems, Inc. and Motorola, Inc. All rights reserved. Use is subject to License Terms. Your use of this web site or any of its content or software indicates your agreement to be bound by these License Terms.

For more information, please consult the JSR 118 specification.