之前的版本，在客户端发送一次请求，服务器返回结果后，运行即终止。
想要服务器可以处理多次请求，需要加入多线程。

加入多线程类，继承自 Runnable

import java.io.IOException;
import java.net.Socket;

import com.test.servlet.Servlet;
import com.test.util.IOCloseUtil;

public class Dispatcher implements Runnable{
    private Request req;
    private Response res;
    private int code = 200;
    private Socket client;
    
    //构造参数初始化属性值
    public Dispatcher(Socket client){
        this.client = client;
        try {
            req = new Request(client.getInputStream());
            res = new Response(client.getOutputStream());
        } catch (IOException e) {
            code = 500;
            return;
        }
        
    }
    
    @Override
    public void run() {
        //根据不同的URL，创建Servlet对象
        Servlet servlet = WebApp.getServlet(req.getUrl());
        if(servlet == null){
            code = 404;
        }else{
            try {
                servlet.Service(req, res);
            } catch (Exception e) {
                code = 500;
            }
        }
        
        res.push2Client(code);
        IOCloseUtil.closeAll(client);
    }
}

修改Server类，加入多线程元素

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

import com.test.util.IOCloseUtil;

/**
 * 服务的启动与停止
 * @author Administrator
 *
 */
public class Server {
    private ServerSocket server;
    private boolean isShutdown = false;
    
    public static void main(String[] args) {
        Server ss = new Server();
        ss.start(8888);
    }
    
    //开启服务
    public void start(int port){
        try {
            this.server = new ServerSocket(port);
            this.receive();
        } catch (IOException e) {
            isShutdown = true;
        }
    }
    
    //接收请求
    public void receive(){
        while(!isShutdown){
            try {
                Socket client = server.accept();
                //加入多线程
                Dispatcher dis = new Dispatcher(client);
                new Thread(dis).start();
            } catch (IOException e) {
                shutdown();
            }
        }
    }
    
    public void shutdown(){
        isShutdown = true;
        IOCloseUtil.closeAll(server);
    }
}