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;
            }
        }
    }
}