DataInputStream和DataOutputStream分别继承字节流InputStream和OutputStream，它属于处理流，需要分别“套接”在InputStream和OutputStream类型的节点流上。

　　DataInputStream和DataOutputStream提供了可以存取与机器无关的Java原始类型数据（如int，double等）的方法。

　　DataInputStream和DataOutputStream的构造方法：

• DataInputStream(InputStream in)
• DataOutputStream(OutputStream out)

　　ByteArrayInputStream和ByteArrayOutputStream的构造器和方法：

Constructor	Description
​(byte[] buf)	Creates a  ByteArrayInputStream so that it uses  buf as its buffer array.
​(byte[] buf, int offset, int length)	Creates  ByteArrayInputStream that uses  buf as its buffer array.

 

All MethodsInstance MethodsConcrete Methods

Modifier and Type	Method	Description
int	​()	Returns the number of remaining bytes that can be read (or skipped over) from this input stream.
void	​()	Closing a  ByteArrayInputStream has no effect.
void	​(int readAheadLimit)	Set the current marked position in the stream.
boolean	​()	Tests if this  InputStream supports mark/reset.
int	​()	Reads the next byte of data from this input stream.
int	​(byte[] b, int off, int len)	Reads up to  len bytes of data into an array of bytes from this input stream.
void	​()	Resets the buffer to the marked position.
long	​(long n)	Skips  n bytes of input from this input stream.

 

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

 

All MethodsInstance MethodsConcrete MethodsDeprecated Methods

Modifier and Type	Method	Description
void	​()	Closing a  ByteArrayOutputStream has no effect.
void	​()	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	​()	Returns the current size of the buffer.
byte[]	​()	Creates a newly allocated byte array.
	​()	Converts the buffer's contents into a string decoding bytes using the platform's default character set.
	​(int hibyte)	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.
	​( charsetName)	Converts the buffer's contents into a string by decoding the bytes using the named  .
void	​(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	​(int b)	Writes the specified byte to this byte array output stream.
void	​( 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).

 

1 package com.zyjhandsome.io; 2  3 import java.io.*; 4  5 public class TestDataStream { 6  7     public static void main(String[] args) { 8         // TODO Auto-generated method stub 9         ByteArrayOutputStream baos = new ByteArrayOutputStream();10         DataOutputStream dos = new DataOutputStream(baos);11         12         try {13             dos.writeDouble(Math.random());14             dos.writeBoolean(true);15             ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());16             // bais.available()方法返回其占用的字节数目，double（8-byte）+boolean（1-byte）=9-byte17             System.out.println(bais.available());18             DataInputStream dis = new DataInputStream(bais);19             // 先存进去的是Double类型数据+Boolean类型的数据20             // 因此在读取时，也应该给先读取Double类型数据+Boolean类型的数据21             System.out.println(dis.readDouble());22             System.out.println(dis.readBoolean());23             dos.close();24             dis.close();            25         } catch (IOException e) {26             // TODO Auto-generated catch block27             e.printStackTrace();28         }        29     }30 }

　　输出结果：

1 92 0.037914917021446563 true