public static void main(String args[]) {
try {
if (args.length != 1)
throw new IllegalArgumentException("Wrong number of args");
// Get the port from the command line
int port = Integer.parseInt(args[0]);
// Create a socket to listen on the port.
DatagramSocket dsocket = new DatagramSocket(port);
// Create a buffer to read datagrams into. If anyone sends us a
// packet containing more than will fit into this buffer, the
// excess will simply be discarded!
byte[] buffer = new byte[2048];
// Create a packet to receive data into the buffer
DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
// Now loop forever, waiting to receive packets and printing them.
for(;;) {
// Wait to receive a datagram
dsocket.receive(packet);
// Convert the contents to a string, and display them
String msg = new String(buffer, 0, packet.getLength());
System.out.println(packet.getAddress().getHostName() +
": " + msg);
// Reset the length of the packet before reusing it.
// Prior to Java 1.1, wed just create a new packet each time.
packet.setLength(buffer.length);
}
}
catch (Exception e) {
System.err.println(e);
System.err.println