import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
public class UDP0 {
// command line arguments:
// r -- read an incoming packet
// w hostname word -- write word to hostname
public static void main(String[] args) throws Exception {
byte[] ary = new byte[128];
DatagramPacket pack = new DatagramPacket(ary, 128);
if (args[0].charAt(0) == 'r') {
// read
DatagramSocket sock = new DatagramSocket(1111);
sock.receive(pack);
String word = new String(pack.getData());
System.out.println("From: " + pack.getAddress() + " Port: "
+ pack.getPort());
System.out.println(word);
sock.close();
} else { // write
DatagramSocket sock = new DatagramSocket();
pack.setAddress(InetAddress.getByName(args[1]));
pack.setData(args[2].getBytes());
pack.setPort(1111);
sock.send(pack);
sock.close();
}
}
}