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Java Examples - ServerSocket and Socket communications examples

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The following example demonstrates how to implement a client sends a message to the server, the server receives the message and read the output, then write to the client the client receives the output.

1, to establish the server

  • ServerSocket server to establish communications
  • Socket receiving client server to establish the connection
  • Establish a data input stream to read IO sent by the client
  • Establishment of IO down to the client to send data messages

Server-side code: 

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {
   public static void main(String[] args) {
      try {
         ServerSocket ss = new ServerSocket(8888);
         System.out.println("启动服务器....");
         Socket s = ss.accept();
         System.out.println("客户端:"+s.getInetAddress().getLocalHost()+"已连接到服务器");
         
         BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));
         //读取客户端发送来的消息
         String mess = br.readLine();
         System.out.println("客户端："+mess);
         BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));
         bw.write(mess+"\n");
         bw.flush();
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
}

The above code is run output is: 

启动服务器....

2, the establishment of the client

  • Create Socket Communications, set the communications server IP and Port
  • Establish IO output data flow server sends a message
  • Establish IO input stream to read the data message sent by the server

Client code: 

/*
 author by w3cschool.cc
 Main.java
 */

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.Socket;
import java.net.UnknownHostException;

public class Client {
   public static void main(String[] args) {
      try {
         Socket s = new Socket("127.0.0.1",8888);
         
         //构建IO
         InputStream is = s.getInputStream();
         OutputStream os = s.getOutputStream();
         
         BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os));
         //向服务器端发送一条消息
         bw.write("测试客户端和服务器通信，服务器接收到消息返回到客户端\n");
         bw.flush();
         
         //读取服务器返回的消息
         BufferedReader br = new BufferedReader(new InputStreamReader(is));
         String mess = br.readLine();
         System.out.println("服务器："+mess);
      } catch (UnknownHostException e) {
         e.printStackTrace();
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
}

The above code is run output is: 

服务器：测试客户端和服务器通信，服务器接收到消息返回到客户端

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