1、連線的客戶端實體類

package com.example.demo.socket3;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;

public class User {

    private String name;
    private String account;
    private Socket socket;
    private BufferedReader br;
    private PrintWriter pw;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAccount() {
        return account;
    }

    public void setAccount(String account) {
        this.account = account;
    }

    public Socket getSocket() {
        return socket;
    }

    public void setSocket(final Socket socket) {
        this.socket = socket;
    }

    public BufferedReader getBr() {
        return br;
    }

    public void setBr(BufferedReader br) {
        this.br = br;
    }

    public PrintWriter getPw() {
        return pw;
    }

    public void setPw(PrintWriter pw) {
        this.pw = pw;
    }

    public User(String name, final Socket socket) throws IOException {
        this.name = name;
        this.socket = socket;
        this.br = new BufferedReader(new InputStreamReader(
                socket.getInputStream()));
        this.pw = new PrintWriter(socket.getOutputStream());
    }

    @Override
    public String toString() {
        return "User [name=" + name + ", account=" + account + ", socket="
                + socket + "]";
    }
}
 

2、服務端

package com.example.demo.socket3;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;
/**
 * 服務端
 * Created by Administrator on 2018/4/11.
 */
public class Server {

    private static final Logger logger = LoggerFactory.getLogger(Server.class);
    public static void main(String[] args) throws Exception {

        // 例項化一個list,用於儲存所有的User
        List<User> list = new ArrayList<User>();
        // 建立繫結到特定埠的伺服器套接字
        ServerSocket serverSocket = new ServerSocket(9999);
        // 迴圈監聽客戶端連線
        while (true) {
            logger.info("服務端啟動,開始監聽客戶端連線....");
            Socket socket = serverSocket.accept();

            // 每接受一個執行緒，就隨機生成一個一個新使用者
            User user = new User("user" + Math.round(Math.random() * 100),socket);
            logger.info(user.getName() + "登入...");
            list.add(user);
            // 建立一個新的執行緒，接收資訊並轉發
            ServerThread thread = new ServerThread(user, list);
            thread.start();
        }
    }
}
 

3、服務端監聽客戶端的方法

package com.example.demo.socket3;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

/**   伺服器執行緒的作用主要是:
 *   1.接收來自客戶端的資訊
 *   2.將接收到的資訊解析，並轉發給目標客戶端
 */
public class ServerThread extends Thread {

    private static final Logger logger = LoggerFactory.getLogger(ServerThread.class);
    private User user;
    private List<User> list;

    public ServerThread(User user, List<User> list) {
        this.user = user;
        this.list = list;
    }

    public void run() {
        try {
            while (true) {
                // 資訊的格式：(login||logout||say),傳送人,收發人,資訊體
                //不斷地讀取客戶端發過來的資訊
                String msg= user.getBr().readLine();
                logger.info("讀取到的資料"+msg);
                String[] str = msg.split(",");
                switch (str[0]) {
                    case "logout":
                        remove(user);// 移除使用者
                        break;
                    case "say":
                        sendToClient(str[1], msg); // 轉發資訊給特定的使用者
                        break;
                    default:
                        break;
                }
            }
        } catch (Exception e) {
            System.err.println("出現異常：使用者斷開，但沒有從列表中移除");
        } finally {
            try {
                user.getBr().close();
                user.getSocket().close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 傳送給指定使用者
     * @param username
     * @param msg
     */
    private void sendToClient(String username, String msg) {
        // 遍歷所有連線使用者，判斷是否存在，存在就把資訊傳送過去
        for (User user : list) {
            if (user.getName().equals(username)) {
                try {
                    PrintWriter pw =user.getPw();
                    pw.println(msg);
                    pw.flush();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    }

    private void remove(User user2) {
        list.remove(user2);
    }
}
 

4、客戶端

package com.example.demo.socket3;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;

/**   client執行緒主要是負責：
 *   1.傳送資訊
 *   2.一直接收資訊，並解析
 */
public class Client {

    public static void main(String[] args) {
        try {
            Socket socket = new Socket("localhost", 9999);
            //開啟一個執行緒接收資訊，並解析
            ClientThread thread=new ClientThread(socket);
            thread.start();

            //主執行緒用來發送資訊
            BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
            PrintWriter out=new PrintWriter(socket.getOutputStream());
            while(true)
            {
                String s=br.readLine();
                out.println(s);
                //         out.write(s+"\n");
                out.flush();
            }
        }catch(Exception e){
            System.out.println("伺服器異常");
        }
    }
}

5、客戶端監聽服務端資訊的方法

package com.example.demo.socket3;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.Socket;

/**
 * 作用：一直接收服務端轉發過來的資訊
 */
public class ClientThread extends Thread {

    private Socket socket;

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

    public void run() {
        try {
            InputStream inputStream = socket.getInputStream();
            InputStreamReader inputStreamReader = new InputStreamReader(
                    inputStream);
            BufferedReader br = new BufferedReader(inputStreamReader);
            try {
                // 資訊的格式：(login||logout||say),傳送人,收發人,資訊體
                while (true) {
                    String msg = br.readLine();
                    System.out.println(msg);
                    String[] str = msg.split(",");
                    switch (str[0]) {
                        case "say":
                            System.out.println(str[2] + " 對   " + str[1] + " say: "
                                    + str[3]);
                            break;
                        default:
                            break;
                    }
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        } catch (IOException e1) {
            e1.printStackTrace();
        }
    }
}

轉載自 https://blog.csdn.net/dreameer_dd/article/details/52626089