Java tutorial
import java.math.BigDecimal; import java.math.BigInteger; import java.util.Calendar; import java.util.Date; /** * 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. */ /** * A suite of utilities surrounding the use of the * {@link java.util.Calendar} and {@link java.util.Date} object. * * DateUtils contains a lot of common methods considering manipulations * of Dates or Calendars. Some methods require some extra explanation. * The truncate and round methods could be considered the Math.floor(), * Math.ceil() or Math.round versions for dates * This way date-fields will be ignored in bottom-up order. * As a complement to these methods we've introduced some fragment-methods. * With these methods the Date-fields will be ignored in top-down order. * Since a date without a year is not a valid date, you have to decide in what * kind of date-field you want your result, for instance milliseconds or days. * * * * * @author <a href="mailto:sergek@lokitech.com">Serge Knystautas</a> * @author Stephen Colebourne * @author Janek Bogucki * @author <a href="mailto:ggregory@seagullsw.com">Gary Gregory</a> * @author Phil Steitz * @author Robert Scholte * @since 2.0 * @version $Id: DateUtils.java 634096 2008-03-06 00:58:11Z niallp $ */ public class Main { //----------------------------------------------------------------------- /** * Checks if two date objects are on the same day ignoring time. * * 28 Mar 2002 13:45 and 28 Mar 2002 06:01 would return true. * 28 Mar 2002 13:45 and 12 Mar 2002 13:45 would return false. * * * @param date1 the first date, not altered, not null * @param date2 the second date, not altered, not null * @return true if they represent the same day * @throws IllegalArgumentException if either date is <code>null</code> * @since 2.1 */ public static boolean isSameDay(Date date1, Date date2) { if (date1 == null || date2 == null) { throw new IllegalArgumentException("The date must not be null"); } Calendar cal1 = Calendar.getInstance(); cal1.setTime(date1); Calendar cal2 = Calendar.getInstance(); cal2.setTime(date2); return isSameDay(cal1, cal2); } /** * Checks if two calendar objects are on the same day ignoring time. * * 28 Mar 2002 13:45 and 28 Mar 2002 06:01 would return true. * 28 Mar 2002 13:45 and 12 Mar 2002 13:45 would return false. * * * @param cal1 the first calendar, not altered, not null * @param cal2 the second calendar, not altered, not null * @return true if they represent the same day * @throws IllegalArgumentException if either calendar is <code>null</code> * @since 2.1 */ public static boolean isSameDay(Calendar cal1, Calendar cal2) { if (cal1 == null || cal2 == null) { throw new IllegalArgumentException("The date must not be null"); } return (cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) && cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) && cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR)); } }