一、需求文档

使用TCP协议支持与多个客户端同时通信。

1.1 Client

package com.itheima.tcp2;

import java.io.DataOutputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.util.Scanner;

public class Client {
    public static void main(String[] args) throws Exception {
        //1、创建socket对象，并同时请求与服务端程序的连接
        Socket socket = new Socket("127.0.0.1",8888);

        //2、从socket通信管道中得到一个字节输出流，用来发数据给服务端程序
        OutputStream os = socket.getOutputStream();

        //3、把低级的字节输出流包装成数据输出流
        DataOutputStream dos = new DataOutputStream(os);

        Scanner sc = new Scanner(System.in);

        while (true) {
            System.out.println("请说：");
            String msg = sc.nextLine();

            //退出
            if ("exit".equals(msg)) {
                System.out.println("欢迎下次光临！退出成功");
                dos.close();
                socket.close();
                break;
            }

            //4、开始写数据出去
            dos.writeUTF(msg);
            dos.flush();
        }
    }
}

1.2 Server

package com.itheima.tcp2;

import java.io.DataInputStream;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {
    public static void main(String[] args) throws Exception {
        //启动服务端
        System.out.println("-----服务端启动成功------");

        //1、创建serversocket对象，同时为服务端程序注册端口
        ServerSocket serverSocket = new ServerSocket(8888);

        while (true) {
            //2、使用serverSocket对象，调用accept方法，等待客户端的连接请求
            Socket socket = serverSocket.accept();

            System.out.println("有人上线了" + socket.getRemoteSocketAddress());

            //3、把这个客户端对于的socket通信管道，交给一个独立的线程负责处理
            new ServerReaderThread(socket).start();
        }
    }
}

1.3 ServerReaderThread

package com.itheima.tcp2;

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

public class ServerReaderThread extends Thread{
    private Socket socket;

    public ServerReaderThread(Socket socket) {
        this.socket = socket;
    }

    @Override
    public void run() {
        try {
            InputStream is = socket.getInputStream();
            DataInputStream dis = new DataInputStream(is);
            while (true) {
                try {
                    String msg = dis.readUTF();
                    System.out.println(msg);
                } catch (Exception e) {
                    System.out.println("有人下线了！" + socket.getRemoteSocketAddress());
                    dis.close();
                    socket.close();
                    break;
                }
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }

    }
}

二、运行结果

客户端1

客户端2

客户端3

服务端