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

public class Client {
    public static void main(String[] args) throws Exception {
        
        Socket s = new Socket("localhost",8888);
        
        //向服务器发送消息
        InputStreamReader r = new InputStreamReader(System.in);
        BufferedReader br = new BufferedReader(r);
        System.out.println("Input your want to write : " );
        String msg = br.readLine();
        
        OutputStream os = s.getOutputStream();
        
        DataOutputStream ds = new DataOutputStream(os);
        ds.writeUTF(msg);
        
        //接受来自服务器的消息
        InputStream r1 = s.getInputStream();
        DataInputStream dis = new DataInputStream(r1);
        String serverMsg = dis.readUTF();
        System.out.println("Reverse the Server massage is : " + serverMsg );
        
        br.close();
        s.close();
    }
}

 1 import java.net.*;
 2 import java.io.* ;
 3 
 4 public class Server {
 5     public static void main(String[] args) throws Exception {
 6         ServerSocket serverSocket = new ServerSocket(8888);
 7         while(true) {
 8             
 9             //接受客户端消息
10             Socket socket = serverSocket.accept();
11             System.out.println("a client connect this server !");
12             InputStream r = socket.getInputStream();
13         
14             DataInputStream dis = new DataInputStream(r);
15             String clientMsg = dis.readUTF();
16             System.out.println("send to this server : " + clientMsg);
17             
18             //向客户端回复消息
19             BufferedReader input = new BufferedReader(
20                 new InputStreamReader(System.in)
21             );
22             String backMsg = input.readLine();
23             OutputStream os = socket.getOutputStream();
24             DataOutputStream dos = new DataOutputStream(os);
25             dos.writeUTF(backMsg);
26             input.close();
27         }
28     }
29 }