Java tutorial
package beans; /* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import java.io.IOException; import java.net.InetAddress; import org.apache.commons.net.time.TimeTCPClient; import org.apache.commons.net.time.TimeUDPClient; /*** * This is an example program demonstrating how to use the TimeTCPClient * and TimeUDPClient classes. * This program connects to the default time service port of a * specified server, retrieves the time, and prints it to standard output. * See <A HREF="ftp://ftp.rfc-editor.org/in-notes/rfc868.txt"> the spec </A> * for details. The default is to use the TCP port. Use the -udp flag to * use the UDP port. * <p> * Usage: TimeClient [-udp] <hostname> * <p> ***/ public final class TimeClient { public static final void timeTCP(String host) throws IOException { TimeTCPClient client = new TimeTCPClient(); try { // We want to timeout if a response takes longer than 60 seconds client.setDefaultTimeout(60000); client.connect(host); System.out.println(client.getDate()); } finally { client.disconnect(); } } public static final void timeUDP(String host) throws IOException { TimeUDPClient client = new TimeUDPClient(); // We want to timeout if a response takes longer than 60 seconds client.setDefaultTimeout(60000); client.open(); System.out.println(client.getDate(InetAddress.getByName(host))); client.close(); } public static void main(String[] args) { args = new String[] { "pool.ntp.org" }; if (args.length == 1) { try { timeTCP(args[0]); } catch (IOException e) { e.printStackTrace(); System.exit(1); } } else if (args.length == 2 && args[0].equals("-udp")) { try { timeUDP(args[1]); } catch (IOException e) { e.printStackTrace(); System.exit(1); } } else { System.err.println("Usage: TimeClient [-udp] <hostname>"); System.exit(1); } } }