Socket群聊

服务端：

package test.chat;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.Iterator;

/**
 * @author Cris
 * @version 1.0
 * @className TestServer
 * @description <功能描述>
 * @date 2020/1/24 23:36
 */
public class TestServer {
    //装入连接的socket对象
    private static ArrayList<Socket> online = new ArrayList<>();
    public static void main(String[] args) throws IOException {
        //创建服务器
        ServerSocket server = new ServerSocket(9988);
        boolean flag =true;
        while(flag) {
            //将连接的socket对象保存到online中
            Socket socket = server.accept();
            online.add(socket);
            //创建线程并启动
            MyThread myThread = new MyThread(socket);
            myThread.start();
        }
        //这个没起到作用，我暂时不知道怎么跳出循环
        server.close();
    }
    //匿名内部类
    private static class MyThread extends Thread{
        private Socket socket;

        public MyThread(Socket socket) {
            super();
            this.socket = socket;
        }

        @Override
        public void run() {
            try {
                //获得输入流
                InputStream is = socket.getInputStream();
                InputStreamReader isr = new InputStreamReader(is);
                BufferedReader br = new BufferedReader(isr);
                String content;
                while((content = br.readLine()) != null){
                    if("再见".equals(content)){//收到再见后，回复一句，客户端下线
                        //不回复客户端一直在等待别人发消息，暂时没有想到办法解决
                        OutputStream os = socket.getOutputStream();
                        PrintStream ps = new PrintStream(os);
                        ps.println("服务器跟您说再见！");
                        break;
                    }
                    sendMessageToOthers(socket.getInetAddress().getHostAddress()+"说："+content);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        public void sendMessageToOthers(String str){
            Iterator<Socket> iterator = online.iterator();
            //当ArrayList中还有socket对象，取出来
            while(iterator.hasNext()) {
                Socket online = iterator.next();
                //不给自己发送消息
                if(!online.equals(socket)) {
                    try {
                        OutputStream os = online.getOutputStream();
                        PrintStream ps = new PrintStream(os);
                        ps.println(str);
                    } catch (IOException e) {
                        //出现异常，该客户掉线
                        iterator.remove();
                    }
                }
            }
        }
    }
}

客户端：

package test.chat;

import java.io.*;
import java.net.Socket;
import java.util.Scanner;

/**
 * @author Cris
 * @version 1.0
 * @className TestClient
 * @description <功能描述>
 * @date 2020/1/24 23:35
 */
public class TestClient {
    public static void main(String[] args) throws IOException {
        Socket socket = new Socket("192.168.31.195",9988);
        //启动线程
        SendThread sendThread = new SendThread(socket);
        ReciveThread reciveThread = new ReciveThread(socket);
        sendThread.start();
        reciveThread.start();
        //对主线程加塞，等待发送完数据
        try {
            sendThread.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        //数据发送完也就意味着不再接收
        reciveThread.setFlag(false);
        //再次对主线程进行加塞，等到数据接收完
        try {
            reciveThread.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        //关闭socket
        socket.close();
    }
}
class SendThread extends Thread{
    private Socket socket;

    public SendThread(Socket socket) {
        super();
        this.socket = socket;
    }
    @Override
    public void run() {
        try {
            while(true) {//一直在输入
                //键盘输入
                System.out.println("请输入要发送的消息：");
                Scanner input = new Scanner(System.in);
                String content = input.next();
                //将输入的内容发送到服务器
                OutputStream os = socket.getOutputStream();
                PrintStream ps = new PrintStream(os);
                ps.println(content);
                if ("再见".equals(content)) {//"再见"意味着结束输入
                    break;
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}
class ReciveThread extends Thread{
    private Socket socket;
    private boolean flag = true;

    public ReciveThread(Socket socket) {
        super();
        this.socket = socket;
    }
    @Override
    public void run() {
        try {
            //接收服务器传来的消息
            InputStream is = socket.getInputStream();
            InputStreamReader isr = new InputStreamReader(is);
            BufferedReader br = new BufferedReader(isr);
            while(flag){//当flag为false时不再接收
                String content = br.readLine();
                System.out.println(content);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public void setFlag(boolean flag) {
        this.flag = flag;
    }
}