java网络编程之socket

基于tcp双向传输，socket编程共用信息流来接收和发送数据。

重点在于理解对不同端来说，输入与输出流的关系。对客户端来说，服务端的输出是客户端的输入。

对服务端来说，客户端的输出是服务端的输入。

import java.io.*;
import java.net.*;

public class Client {
 
   public static void main(String args[]) throws Exception {
    
      
       //为了简单起见，所有的异常都直接往外抛
       String host = "127.0.0.1";  //要连接的服务端IP地址
       int port = 8899;   //要连接的服务端对应的监听端口
       //与服务端建立连接
       Socket client = new Socket(host, port);
       //建立连接后就可以往服务端写数据了
       BufferedReader is = new BufferedReader(new InputStreamReader(client.getInputStream()));
       
       BufferedReader sin = new BufferedReader(new InputStreamReader(System.in));
       
       
       PrintWriter os = new PrintWriter(client.getOutputStream());
       
       String s;
       s = sin.readLine();
       os.println(s);
       os.flush();
       System.out.println("Server:"+is.readLine());
       
       
       
       os.close();
       is.close();
       client.close();
   }
   
}

import java.io.*;
import java.net.*;

public class Server {
 
   public static void main(String args[]) throws IOException {
       //端口
       int port = 8899;
       //建立服务端socket
       ServerSocket server = new ServerSocket(port);
       Socket socket = server.accept();
       
       BufferedReader is = new BufferedReader(new InputStreamReader(socket.getInputStream()));
       
       PrintWriter os = new PrintWriter(socket.getOutputStream());
       
       BufferedReader sin = new BufferedReader(new InputStreamReader(System.in));
       
       String s = is.readLine();
       //获取客户端的输入流
       System.out.println("client:"+s);
       if(s.equals("hello")){
           os.println("你好");
           os.flush();
       }else{
           System.out.println("bye");
       }
       

       is.close();
       os.close();
       socket.close();
       server.close();
   }
   
}