19. UDP 编程

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;

public class Udp {

public static void main(String[] args) {
try {
DatagramSocket ds = new DatagramSocket(9998);
String str = "1234";
DatagramPacket dp = new DatagramPacket(str.getBytes(), str.length(), InetAddress.getByName("localhost"),
9999);
ds.send(dp);
byte[] buff = new byte[1024];
DatagramPacket dp2 = new DatagramPacket(buff, 1024);
ds.receive(dp2);
String result = new String(dp2.getData(), 0, dp2.getLength());
ds.close();
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}

}