两台电脑之间怎么实现互通交流

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.util.Scanner;

public class Chat {
  public static void main(String[] args) {
    DatagramSocket sendsocket = null;
    DatagramSocket receiceSocket = null;
    try {
      sendsocket = new DatagramSocket();
      receiceSocket = new DatagramSocket(8888,InetAddress.getByName("127.0.0.1"));
    } catch (SocketException e) {
      e.printStackTrace();
    } catch (UnknownHostException e) {
      e.printStackTrace();
    }
    new Thread(new Send(sendsocket)).start();
    new Thread(new Receive(receiceSocket)).start();
  }
}
class Send implements Runnable{
  DatagramSocket socket = null;
  public Send(DatagramSocket socket) {
    this.socket = socket;
  }
  @Override
  public void run() {
    byte[] buf = new byte[1024];
    DatagramPacket packet = null;
    Scanner scanner = new Scanner(System.in);
    while(true) {
      String data = scanner.nextLine();
      if("over".equalsIgnoreCase(data)) {
        break;
      }
      buf = data.getBytes();
      try {
        //接收方的IP和端口号
        packet = new DatagramPacket(buf, buf.length, InetAddress.getByName("127.0.0.1"), 9999);
        socket.send(packet);
      } catch (UnknownHostException e) {
        e.printStackTrace();
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
    scanner.close();
  }
}
class Receive implements Runnable{
  DatagramSocket socket;
  public Receive(DatagramSocket socket) {
    this.socket = socket;
  }
  @Override
  public void run() {
    while(true) {
      byte[]buf = new byte[1024];
      DatagramPacket packet = new DatagramPacket(buf, buf.length);
      try {
        socket.receive(packet);
      } catch (IOException e) {
        e.printStackTrace();
        break;
      }
      String text = new String(packet.getData(), 0, packet.getLength());
      String ip = packet.getAddress().getHostAddress();
      if("over".equalsIgnoreCase(text)) {
        break;
      }
      System.out.println(ip+" : "+text);
    }
    socket.close();
  }
  
}
		

DatagramSocket ds = new DatagramSocket();
byte[] by = “hello,udp”.getBytes();
DatagramPacket dp = new DatagramPacket(by,0,by.length,
  InetAddress.getByName(“127.0.0.1”),10000);
ds.send(dp);
ds.close();