网络Socket编程TCP协议例子

1.单线程TCP服务端

 public class TcpChatServer {

     private Integer port=8000;
     private ServerSocket serverSocket;

     public static void main(String[] args)throws Exception  {

         new TcpChatServer().service();
     }

     public TcpChatServer() throws Exception {
         //启动一个服务监听一个指定的端口port
         serverSocket=new ServerSocket(port);
         System.out.println("service started!");
     }

     private void service(){
         while (true) {
             Socket socket=null;
             try {
                 //serversocket开始监听服务，客户端和服务端交互的socket
                 socket=serverSocket.accept();
                 System.out.println(String.format("client:%s port:%s",socket.getInetAddress(),socket.getPort()));
                 //获取客户端的数据对象
                 BufferedReader reader=new BufferedReader(new InputStreamReader(socket.getInputStream()));
                 //写入客户端的数据对象
                 PrintWriter writer=new PrintWriter(socket.getOutputStream(),true);
                 String word;
                 while ((word=reader.readLine())!=null) {
                     //相应请求
                     writer.println(reply(word));
                     //如果用户输入bye则退出循环
                     if(word.equals("bye")){
                         break;
                     }
                 }
             } catch (IOException e) {
                 System.err.println(e.getMessage());
             }finally{
                 //一定要关闭socket
                 if(socket!=null){
                     try {
                         socket.close();
                     } catch (IOException e) {
                         System.err.println(e.getMessage());
                     }
                 }
             }
         }
     }

      //回复相应
     private String reply(String word){
         return "you said :"+word;
     }
 }

运行...在cmd下访问....使用telnet访问....

但是有一个问题...如果再开一个telnet访问的话输入什么都是没有效果的...只有等到第一个结束之后才会对第二个访问的telnet进行回复,如下图.

搞一个多线程的Socket服务端.

 public class TcpThreadChatServer {

     private Integer port=8000;
     private ServerSocket serverSocket;

     public static void main(String[] args)throws Exception  {

         new TcpThreadChatServer().service();
     }

     public TcpThreadChatServer() throws Exception {
         //启动一个服务监听一个指定的端口port
         serverSocket=new ServerSocket(port);
         System.out.println("service started!");

     }

     private void service(){

         while (true) {
             Socket socket=null;

             try {
                 //serversocket开始监听服务，客户端和服务端交互的socket
                 socket=serverSocket.accept();
                 //对于每次请求,多线程应答  可以开多个可以对多个客户端进行回应.
                 new Thread(new Worker(socket)).start();
             } catch (IOException e) {
                 System.err.println(e.getMessage());
             }
         }
     }

     class Worker implements Runnable{
         public Worker(Socket socket) {
             this.socket = socket;
         }
         private Socket socket;

         @Override
         public void run() {

             try {
                 System.out.println(String.format("client:%s port:%s",socket.getInetAddress(),socket.getPort()));
                 //获取客户端的数据对象
                 BufferedReader reader=new BufferedReader(new InputStreamReader(socket.getInputStream()));
                 //写入客户端的数据对象
                 PrintWriter writer=new PrintWriter(socket.getOutputStream(),true);
                 String word;
                 while ((word=reader.readLine())!=null) {
                     //相应请求
                     writer.println(reply(word));
                     //如果用户输入bye则退出循环
                     if(word.equals("bye")){
                         break;
                     }
                 }
             } catch (Exception e) {
                 System.err.println(e.getMessage());
             }finally{
                 if(socket!=null){
                     try {
                         socket.close();
                     } catch (IOException e) {
                         System.err.println(e.getMessage());
                     }
                 }
             }
         }
     }

      //回复相应
     private String reply(String word){
         return "you said :"+word;
     }
 }

可以开启多个telnet访问 并同时处理反馈.....

可以写对应的如下客户端...通过控制台访问该服务端,不再使用telnet...

 public class TcpChatClient {//客户端和服务端通话都是过socket

     private Socket socket;
     private String host="localhost";//要请求的服务器地址
     private Integer port=8000;

     public TcpChatClient() throws Exception {
         //初始化一个客户端socket
         socket=new Socket(host, port);
         System.out.println("connect ok!");
     }

     public static void main(String[] args) throws Exception {

         new TcpChatClient().say();
     }

     private void say() throws Exception {
         //两个reader对象
         //本地的system.in 的reader
         BufferedReader localReader=new BufferedReader(new InputStreamReader(System.in));
         //和服务器交互的writer【PrintWriter 的自动flush 功能】  这个ture参数非常重要  .
         PrintWriter writer=new PrintWriter(socket.getOutputStream(),true);
         //和服务器交互的reader
         BufferedReader reader=new BufferedReader(new InputStreamReader(socket.getInputStream()));

         String word;
         String readLine;
         while ((word=localReader.readLine())!=null){
             //请求服务端来获取数据
             writer.println(word);
             //打印到控制台上
             readLine = reader.readLine();
             System.out.println(readLine);

             //如果用户输入bye则退出循环
             if (word.equals("bye")){
                 socket.close();
                 break;
             }
         }
     }
 }