import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

//接收方
public class UDPChatUser_1 {

    public static void main(String[] args) throws Exception {
        // TODO Auto-generated method stub
        int port = 10000;

        DatagramSocket Clintds = new DatagramSocket(port);

        byte[] buf = new byte[1024];
        DatagramPacket dp = new DatagramPacket(buf, buf.length);
　　　　 //接收方和发送方执行完之后，接收方一直处于阻塞状态
        Clintds.receive(dp);
        byte[] bufByte = dp.getData();
        System.out.println(new String(bufByte, 0, bufByte.length));
        Clintds.close();
    }

}


//--------------------------------------------------------------
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

//发送方
public class UDPCharUser_2 {

    public static void main(String[] args) throws Exception {
        // TODO Auto-generated method stub
        String str = "你好，UDP！";
        
        DatagramSocket ds = new DatagramSocket(12306);
        
        byte[] strByte = str.getBytes();
//InetAddress ip = InetAddress.getLocalHost();  
        InetAddress ip = InetAddress.getByName("183.158.260.262");
        int port = 10000;
        DatagramPacket dp = 
                new DatagramPacket(strByte, strByte.length, ip , port);
        
        ds.send(dp);
        
        //System.out.println(new String(dp.getData(), 0, dp.getLength()));
        ds.close();
    }

}