import java.io.*; import java.net.*; import java.util.*; class DgramUtils2 { public DatagramPacket buildPkg(InetAddress addr, int port, String msg) { ByteArrayOutputStream bstream = new ByteArrayOutputStream(); DataOutputStream dstream = new DataOutputStream(bstream); byte[] data; try { dstream.writeUTF(msg); } catch (IOException e) { System.out.println("dgramutils: " + e.getMessage()); } data = bstream.toByteArray(); return new DatagramPacket(data, data.length, addr, port); return new DatagramPacket(data, data.length, addr, port); } } public class client { public static final int port = 3333; public static void main(String[] args) { System.setProperty("java.net.preferIPv4Stack" , "true"); InetAddress saddr = null; BufferedReader in = null; DatagramSocket sock = null; if (args.length == 0) { System.out.println("client [address]"); System.exit(1); } } try { sock = new DatagramSocket(); saddr = InetAddress.getByName(args[0]); } catch (SocketException e) { System.out.println("sock err: " + e.getMessage()); System.exit(1); } catch (UnknownHostException e) {} in = new BufferedReader(new InputStreamReader(System.in)); try { while (true) { int n = Integer.parseInt(in.readLine()); System.out.println("n "+n); DgramUtils2 du = new DgramUtils2(); DatagramPacket pkg = du.buildPkg(saddr, port, Integer.toString(n)); sock.send(pkg); DatagramPacket pkg = du.buildPkg(saddr, port, Integer.toString(n)); sock.send(pkg); } } catch (IOException e) { System.out.println("IO: " + e.getMessage()); sock.close(); System.exit(1); } } }