《Java TCP/IP Socket编程》读书笔记(6)

3.2 组合输入输出流

Java中与流相关的类可以组合起来从而提供强大的功能。我们可以将一个Socket实例的OutputStream包装在一个BufferedOutputStream实例中，这样可以先将字节暂时缓存在一起，然后再一次全部发送到底层的通信信道中，以提高程序的性能。我们还能再将这个BufferedOutputStream实例包裹在一个DataOutputStream实例中，以实现发送基本数据类型的功能。以下是实现这种组合的代码：

Socket socket = new Socket(server, port);
DataOutputStream out = new DataOutputStream(
new BufferedOutputStream(socket.getOutputStream()));

下面是一个组合I/O流的例子

完整代码如下所示

服务器端

package com.suifeng.tcpip.chapter3;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketAddress;

public class TCPEchoServer
{

	public static void main(String[] args) throws IOException
	{
		if (args.length != 1)
		{
			throw new IllegalArgumentException("Parameter:<Port>");
		}

		// 获取服务器的端口
		int serverPort = Integer.parseInt(args[0]);

		// 创建用于客户端连接的SocketServer实例
		ServerSocket server = new ServerSocket(serverPort);
		System.out.println("Server has started!!!!\nWaiting data from client.");

		while (true)
		{
			System.out.println("正在等待客户端发送数据");
			Socket socket = server.accept();

			SocketAddress address = socket.getRemoteSocketAddress();
			System.out.println("Handling client at " + address);
			
			// 组合输入流
			DataInputStream dis = new DataInputStream(new BufferedInputStream(
					socket.getInputStream()));
			
			// 读取一个double值
			double value = dis.readDouble();
			System.out.println("Server received Double Value=" + value);
			
			// 读取一个Int值
			int value2 = dis.readInt();
			System.out.println("Server received Int Value=" + value2);
			
			// 读取一个Long值
			long value3 = dis.readLong();
			System.out.println("Server received Long Value=" + value3);
			
			System.out.println("服务器端正在发送数据.....");
			DataOutputStream out = new DataOutputStream(
					new BufferedOutputStream(socket.getOutputStream()));
			out.writeLong(value3);
			out.writeDouble(value);
			out.writeInt(value2);
			System.out.println("服务器端正在发送数据结束");
			out.flush();

			socket.close();
		}
	}

}

客户端

package com.suifeng.tcpip.chapter3;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.Socket;
import java.net.UnknownHostException;

public class TCPEchoClient
{

	/**
	 * @param args
	 * @throws IOException
	 * @throws UnknownHostException
	 */
	public static void main(String[] args) throws UnknownHostException,
			IOException
	{
		if (args.length < 1 || args.length > 2)
		{
			throw new IllegalArgumentException(
					"Parameter(s):<Server> [<Port>]");
		}

		// SerName or IP Address
		String server = args[0];

		// 获取端口号
		int serverPort = (args.length == 2) ? Integer.parseInt(args[1]) : 7;

		// 使用指定的服务器和端口创建Socket
		Socket socket = new Socket(server, serverPort);
		System.out.println("Connected to server ..... Sending echo String");
		
		System.out.println("客户端正在发送数据.....");
		
		// 组合输出流
		DataOutputStream out = new DataOutputStream(new BufferedOutputStream(
				socket.getOutputStream()));
		
		System.out.println("Client Send Double Value=3.14");
		// 先发送一个double值
		out.writeDouble(3.14);
		
		System.out.println("Client Send Int Value=50");
		// 再发送一个int值
		out.writeInt(50);
		
		System.out.println("Client Send Long Value=123333333333333333L");
		// 最后发送一个long值
		out.writeLong(123333333333333333L);
		out.flush();
		
		System.out.println("发送数据结束");
		
		System.out.println("客户端正在接收数据.....");
		DataInputStream dis = new DataInputStream(new BufferedInputStream(
				socket.getInputStream()));
		
		System.out.println("Client received Long Value=" + dis.readLong());
		System.out.println("Client received Double Value=" + dis.readDouble());
		System.out.println("Client received Int Value=" + dis.readInt());
		System.out.println("客户端正在接收数据结束");
		socket.close();
	}
}

先启动服务器端，监听39393端口

启动客户端，想39393端口发送数据

再次查看服务器端