一、服务端

package com.server;import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;/*** @Auther: chenzhou* @Date: 2019/2/25* @Description: 网络编程服务端* @version: 1.0*/
public class Server{public static void main(String[] args) throws Exception {ServerSocket serverSocket = new ServerSocket(9999);//设置端口号System.out.println("等待客户端连接");Socket accept = serverSocket.accept();//首先接收客户端发来的消息，然后进行数据处理后发送回客户端Scanner scanner = new Scanner(accept.getInputStream());//得到客户端发送的数据PrintStream stream = new PrintStream(accept.getOutputStream());//向客户端发送数据Boolean flag = true;while (flag){if(scanner.hasNext()){String next = scanner.next().trim();if("bye".equals(next)){stream.println("ByeBye!!!");flag = false;}else{stream.println("[Echo]"+next);}}}//关闭流stream.close();scanner.close();serverSocket.close();}
}

二、客户端

package com.client;import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.Socket;
import java.util.Scanner;/*** @Auther: chenzhou* @Date: 2019/2/25* @Description: 网络编程客户端* @version: 1.0*/
public class Client {private static final BufferedReader BUFFERED_READER= new BufferedReader(new InputStreamReader(System.in));public static void main(String[] args) throws Exception{Socket socket = new Socket("localhost",9999);Scanner scanner = new Scanner(socket.getInputStream());//服务端发来的信息PrintStream stream = new PrintStream(socket.getOutputStream());//向服务端发送信息Boolean flag = true;while(flag){String input = getString("请输入要发送的内容");stream.println(input);if(scanner.hasNext()){String next = scanner.next();System.out.println(next);}if("bye".equalsIgnoreCase(input)){flag = false;}}stream.close();scanner.close();socket.close();}public static String getString(String Prompt) throws  Exception{System.out.println(Prompt);String s = BUFFERED_READER.readLine();return s;}
}

输出结果：

三、多线程实现服务端（多个客户端连接一个服务端）

package com.server;import java.io.IOException;
import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;/*** @Auther: chenzhou* @Date: 2019/2/25* @Description: 多线程实现服务端，让每个线程去处理客户端的请求* @version: 1.0*/
public  class ServerForMore implements  Runnable{Socket socket = null;Scanner scanner = null;PrintStream stream= null;Boolean flag = true;//构造器初始化参数public  ServerForMore(Socket client) throws Exception {this.socket = client;scanner = new Scanner(client.getInputStream());//得到客户端发送的数据stream = new PrintStream(client.getOutputStream());//向客户端发送消息}@Overridepublic void run() {while (this.flag){if(this.scanner.hasNext()){String next = scanner.next().trim();if("bye".equals(next)){stream.println("ByeBye!!!");flag = false;}else{stream.println("[Echo]"+next);}}}//关闭流stream.close();scanner.close();try {socket.close();} catch (IOException e) {e.printStackTrace();}}public static void main(String[] args) throws Exception {ServerSocket serverSocket = new ServerSocket(9999);System.out.println("等待客户端连接。。。。");Boolean flag = true;while(flag){Socket client = serverSocket.accept();new Thread(new ServerForMore(client)).start();}serverSocket.close();}
}