JAVA_Socket

 1 import java.net.*;
 2 import java.io.*;
 3 
 4 public class TCPServer {
 5     public static void main(String[] args) throws Exception {
 6         ServerSocket ss = new ServerSocket(6666);
 7         while(true) {
 8             Socket s = ss.accept();
 9 System.out.println("a client connect!");
10             DataInputStream dis = new DataInputStream(s.getInputStream());
11             System.out.println(dis.readUTF());
12             Thread.sleep(3000);
13             System.out.println("hello client!");
14             dis.close();
15             s.close();
16         }
17         
18     }
19 }

 1 import java.net.*;
 2 import java.io.*;
 3 
 4 public class TCPClient {
 5     public static void main(String[] args) throws Exception {
 6         Socket s = new Socket("127.0.0.1", 6666);
 7         OutputStream os = s.getOutputStream();
 8         DataOutputStream dos = new DataOutputStream(os);
 9         Thread.sleep(3000);
10         dos.writeUTF("hello server!");
11         dos.flush();
12         dos.close();
13         s.close();
14     }
15 }