学步园

这篇做为学习孙卫琴<<Java网络编程精解>>的学习笔记吧.其中采用Java 5的ExecutorService来进行线程池的方式实现多线程,模拟客户端多用户向同一服务器端发送请求.

1.服务端

package sterning;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.*;
import java.util.concurrent.*;

public class MultiThreadServer {
    private int port=8821;
    private ServerSocket serverSocket;
    private ExecutorService executorService;//线程池
    private final int POOL_SIZE=10;//单个CPU线程池大小
    
    public MultiThreadServer() throws IOException{
        serverSocket=new ServerSocket(port);
        //Runtime的availableProcessor()方法返回当前系统的CPU数目.
        executorService=Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors()*POOL_SIZE);
        System.out.println("服务器启动");
    }
    
    public void service(){
        while(true){
            Socket socket=null;
            try {
                //接收客户连接,只要客户进行了连接,就会触发accept();从而建立连接
                socket=serverSocket.accept();
                executorService.execute(new Handler(socket));
                
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
    
    public static void main(String[] args) throws IOException {
        new MultiThreadServer().service();
    }

}

class Handler implements Runnable{
    private Socket socket;
    public Handler(Socket socket){
        this.socket=socket;
    }
    private PrintWriter getWriter(Socket socket) throws IOException{
        OutputStream socketOut=socket.getOutputStream();
        return new PrintWriter(socketOut,true);
    }
    private BufferedReader getReader(Socket socket) throws IOException{
        InputStream socketIn=socket.getInputStream();
        return new BufferedReader(new InputStreamReader(socketIn));
    }
    public String echo(String msg){
        return "echo:"+msg;
    }
    public void run(){
        try {
            System.out.println("New connection accepted "+socket.getInetAddress()+":"+socket.getPort());
            BufferedReader br=getReader(socket);
            PrintWriter pw=getWriter(socket);
            String msg=null;
            while((msg=br.readLine())!=null){
                System.out.println(msg);
                pw.println(echo(msg));
                if(msg.equals("bye"))
                    break;
            }
        } catch (IOException e) {
            e.printStackTrace();
        }finally{
            try {
                if(socket!=null)
                    socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

2.客户端

package sterning;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.Socket;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class MultiThreadClient {
    
    public static void main(String[] args) {
        int numTasks = 10;
        
        ExecutorService exec = Executors.newCachedThreadPool();

        for (int i = 0; i < numTasks; i++) {
            exec.execute(createTask(i));
        }

    }

    // 定义一个简单的任务
    private static Runnable createTask(final int taskID) {
        return new Runnable() {
            private Socket socket = null;
            private int port=8821;

            public void run() {
                System.out.println("Task " + taskID + ":start");
                try {                    
                    socket = new Socket("localhost", port);
                    // 发送关闭命令
                    OutputStream socketOut = socket.getOutputStream();
                    socketOut.write("shutdown\r\n".getBytes());

                    // 接收服务器的反馈
                    BufferedReader br = new BufferedReader(
                            new InputStreamReader(socket.getInputStream()));
                    String msg = null;
                    while ((msg = br.readLine()) != null)
                        System.out.println(msg);
                } catch (IOException e) {                    
                    e.printStackTrace();
                }
            }

        };
    }
}

从而实现了多个客户端向服务器端发送请求,服务器端采用多线程的方式来处理的情况.再结合我之前的例子---Java基于Socket文件传输示例,就可以实现多线程文件的传输了