Java聊天室

客户端代码：

import java.io.IOException;
import java.io.PrintStream;
import java.net.Socket;
import java.util.Scanner;

class ReadFromServer implements Runnable{
    private Socket client;

    public ReadFromServer(Socket client) {
        this.client = client;
    }

    @Override
    public void run() {
        Scanner readFromServer = null;
        try {
            readFromServer = new Scanner(client.getInputStream());
            readFromServer.useDelimiter("\n");
            while (true){
                if(readFromServer.hasNextInt()){
                    String str = readFromServer.nextLine();
                    System.out.println("服务器说："+str);
                }
                if(client.isClosed()){
                    System.out.println("客户端已经关闭");
                    break;
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            readFromServer.close();
        }
    }
}

class SendMsgToServer implements Runnable{
    private Socket client;

    public SendMsgToServer(Socket client) {
        this.client = client;
    }

    @Override
    public void run() {
        Scanner in = new Scanner(System.in);
        in.useDelimiter("\n");
        PrintStream sendMsgToServer = null;
        try {
            sendMsgToServer = new PrintStream(client.getOutputStream(),true,"UTF-8");
            while (true){
                System.out.println("请输入要发送的信息：");
                if(in.hasNextLine()){
                    String strToServer = in.nextLine().trim();
                    sendMsgToServer.println(strToServer);
                    if(strToServer.contains("byebye")){
                        System.out.println("关闭客户端");
                        break;
                    }
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                client.close();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                sendMsgToServer.close();
                in.close();
            }
        }
    }
}
public class MutiThreadClient {
    public static void main(String[] args) throws IOException {
        Socket client = new Socket("127.0.0.1", 6666);
        Thread readthread = new Thread(new ReadFromServer(client));
        Thread sendthread = new Thread(new SendMsgToServer(client));
        readthread.start();
        sendthread.start();
    }

}

服务器端代码：

import java.io.IOException;
import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Collection;
import java.util.Map;
import java.util.Scanner;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.regex.Matcher;
import java.util.regex.Pattern;


public class MutiThreadServerSocket {
    //使用ConcurrentHashMap,存在线程安全问题
    private static Map<String,Socket> clientsMap = new ConcurrentHashMap<>();
    private static class ExectueClientRequest implements Runnable{
        private Socket client;

        public ExectueClientRequest(Socket client) {
            this.client = client;
        }

        @Override
        public void run() {
            Scanner readFromClient =null;
            try {
                readFromClient = new Scanner(client.getInputStream());
                readFromClient.useDelimiter("\n");
                while (true){
                    if(readFromClient.hasNextLine()){
                        String str = readFromClient.nextLine();
                        /**
                         * 用户注册：userName
                         * 	群聊实现：G:
                         * 	私聊实现：P：zhangsan -
                         */
                        //进行\r过滤 --正则方法
                        Pattern pattern = Pattern.compile("\r");
                        Matcher matcher = pattern.matcher(str);
                        str = matcher.replaceAll("");
                        if (str.startsWith("userName")){
                            String userName = str.split(":")[1];
                            userRegister(userName,client);
                            continue;
                        }
                        if(str.startsWith("G:")){
                            String msg = str.split(":")[1];
                            GroupChat(msg);
                            continue;
                        }
                        if (str.startsWith("P:")){
                            String msg = str.split(":")[1];
                            String username = msg.split("-")[0];
                            String privatemsg = msg.split("-")[1];
                            privateChat(username, privatemsg);
                            continue;
                        }
                        if (str.contains("byebye")){
                            String userName = str.split(":")[0];
                            userExist(userName);
                            continue;
                        }
                    }
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        /**
         * 用户注册方法
         */
        private void userRegister(String userName, Socket client){
            //将用户信息保存到服务器中
            clientsMap.put(userName,client);
            int size = clientsMap.size();
            System.out.println("当前聊天室有"+size+"人");
            String userOnline = userName+"上线了";
            System.out.println(userName+"上线了");
            GroupChat(userOnline);

        }
        /**
         * 群聊流程
         */
        private void GroupChat(String msg){
            Collection<Socket> clients = clientsMap.values();
            for (Socket client : clients){
                try {
                    PrintStream out = new PrintStream(client.getOutputStream(),true,"UTF-8");
                    out.println("群聊信息为："+msg);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        /**
         * 私聊流程
         * @param userName
         * @param msg
         */
        private void privateChat(String userName, String msg){
            Socket client = clientsMap.get(userName);
            try {
                PrintStream out = new PrintStream(client.getOutputStream(),true,"UTF-8");
                out.println(msg);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        /**
         * 退出流程
         * @param userName
         */
        private void userExist(String userName){
            clientsMap.remove(userName);
            String groupChatMsg = userName+"已下线";
            GroupChat(groupChatMsg);
        }
    }

    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(6666);
        ExecutorService service = Executors.newFixedThreadPool(20);
        for(int i = 0; i<20; i++){
            System.out.println("等待客户端连接");
            Socket client = serverSocket.accept();
            System.out.println("有新客户端连接，端口号为："+client.getPort());
            service.submit(new ExectueClientRequest(client));
        }
    }
}

如有不足之处还请见谅，谢谢