| 10 |
|
|
| 11 |
|
public static void main(String[] args) throws IOException { |
| 12 |
|
|
| 13 |
< |
DatagramSocket socket = new DatagramSocket(4589); |
| 13 |
> |
// default UDP listening port. |
| 14 |
> |
int port = 4589; |
| 15 |
> |
final int packetSizeLimit = 8192; |
| 16 |
|
|
| 17 |
+ |
// Allow the user to choose their own port number. |
| 18 |
+ |
if (args.length == 1){ |
| 19 |
+ |
try { |
| 20 |
+ |
port = new Integer(args[0]).intValue(); |
| 21 |
+ |
} |
| 22 |
+ |
catch (Exception e){ |
| 23 |
+ |
// If something went wrong, use the default again. |
| 24 |
+ |
port = 4589; |
| 25 |
+ |
} |
| 26 |
+ |
} |
| 27 |
+ |
|
| 28 |
+ |
DatagramSocket socket = null; |
| 29 |
|
try { |
| 30 |
< |
byte[] buf = new byte[1024]; |
| 17 |
< |
// receive request |
| 18 |
< |
DatagramPacket packet = new DatagramPacket(buf, buf.length); |
| 19 |
< |
socket.receive(packet); |
| 20 |
< |
String dataIn = new String(packet.getData()); |
| 21 |
< |
System.out.println("Received: " + dataIn); |
| 30 |
> |
socket = new DatagramSocket(port); |
| 31 |
|
} |
| 32 |
< |
catch (IOException e) { |
| 33 |
< |
System.out.println("An exception occured!"); |
| 34 |
< |
e.printStackTrace(); |
| 32 |
> |
catch (BindException e){ |
| 33 |
> |
System.out.println("Some other process is already listening on port "+port+"."); |
| 34 |
> |
System.out.println("Please specify another port number on the command line."); |
| 35 |
> |
System.exit(0); |
| 36 |
> |
} |
| 37 |
> |
|
| 38 |
> |
System.out.println("UDPReader ready and listening for UDP packets on port "+port); |
| 39 |
> |
|
| 40 |
> |
byte[] buf; |
| 41 |
> |
UDPReaderThread t = new UDPReaderThread(); |
| 42 |
> |
|
| 43 |
> |
boolean running = true; |
| 44 |
> |
while (running){ |
| 45 |
> |
System.gc(); |
| 46 |
> |
try { |
| 47 |
> |
buf = new byte[packetSizeLimit]; |
| 48 |
> |
// receive request |
| 49 |
> |
DatagramPacket packet = new DatagramPacket(buf, buf.length); |
| 50 |
> |
socket.receive(packet); |
| 51 |
> |
t.run(packet); |
| 52 |
> |
} |
| 53 |
> |
catch (IOException e) { |
| 54 |
> |
System.out.println("An exception occured in the UDPReader!"); |
| 55 |
> |
e.printStackTrace(); |
| 56 |
> |
} |
| 57 |
|
} |
| 58 |
|
socket.close(); |
| 59 |
|
} |