public class

ByteArrayOutputStream

extends OutputStream
java.lang.Object
   ↳ java.io.OutputStream
     ↳ java.io.ByteArrayOutputStream
Known Direct Subclasses

Class Overview

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.

Summary

Fields
protected byte[] buf The buffer where data is stored.
protected int count The number of valid bytes in the buffer.
Public Constructors
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.
Public Methods
void close()
Closing a ByteArrayOutputStream has no effect.
synchronized 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.
synchronized int size()
Returns the current size of the buffer.
synchronized byte[] toByteArray()
Creates a newly allocated byte array.
synchronized String toString(int hibyte)
This method is deprecated. This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the toString(String enc) method, which takes an encoding-name argument, or the toString() method, which uses the platform's default character encoding.
synchronized String toString(String charsetName)
Converts the buffer's contents into a string by decoding the bytes using the specified charsetName.
synchronized String toString()
Converts the buffer's contents into a string decoding bytes using the platform's default character set.
synchronized 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.
synchronized void write(int b)
Writes the specified byte to this byte array output stream.
synchronized 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).
[Expand]
Inherited Methods
From class java.io.OutputStream
From class java.lang.Object
From interface java.io.Closeable
From interface java.io.Flushable

Fields

protected byte[] buf

The buffer where data is stored.

protected int count

The number of valid bytes in the buffer.

Public Constructors

public ByteArrayOutputStream ()

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

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.

Public Methods

public void close ()

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

Throws
IOException

public synchronized 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

public synchronized 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

public synchronized 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

public synchronized String toString (int hibyte)

This method is deprecated.
This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the toString(String enc) method, which takes an encoding-name argument, or the toString() method, which uses the platform's default character encoding.

Creates a newly allocated string. Its size is the current size of the output stream and the valid contents of the buffer have been copied into it. Each character c in the resulting string is constructed from the corresponding element b in the byte array such that: 

     c == (char)(((hibyte & 0xff) << 8) | (b & 0xff))

Parameters
hibyte the high byte of each resulting Unicode character.
Returns
  • the current contents of the output stream, as a string.
See Also

public synchronized String toString (String charsetName)

Converts the buffer's contents into a string by decoding the bytes using the specified charsetName. The length of the new String is a function of the charset, and hence may not be equal to the length of the byte array.

This method always replaces malformed-input and unmappable-character sequences with this charset's default replacement string. The java.nio.charset.CharsetDecoder class should be used when more control over the decoding process is required.

Parameters
charsetName the name of a supported charset
Returns
  • String decoded from the buffer's contents.
Throws
UnsupportedEncodingException If the named charset is not supported

public synchronized 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.

This method always replaces malformed-input and unmappable-character sequences with the default replacement string for the platform's default character set. The java.nio.charset.CharsetDecoder class should be used when more control over the decoding process is required.

Returns
  • String decoded from the buffer's contents.

public synchronized 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.

Parameters
b the data.
off the start offset in the data.
len the number of bytes to write.

public synchronized void write (int b)

Writes the specified byte to this byte array output stream.

Parameters
b the byte to be written.

public synchronized 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).

Parameters
out the output stream to which to write the data.
Throws
IOException if an I/O error occurs.