Java tutorial
import java.math.BigDecimal; import java.math.BigInteger; import java.text.ParseException; import java.text.ParsePosition; import java.text.SimpleDateFormat; 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. */ /** * <p>A suite of utilities surrounding the use of the * {@link java.util.Calendar} and {@link java.util.Date} object.</p> * * <p>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. * </p> * * * * @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 { //----------------------------------------------------------------------- /** * <p>Parses a string representing a date by trying a variety of different parsers.</p> * * <p>The parse will try each parse pattern in turn. * A parse is only deemed sucessful if it parses the whole of the input string. * If no parse patterns match, a ParseException is thrown.</p> * * @param str the date to parse, not null * @param parsePatterns the date format patterns to use, see SimpleDateFormat, not null * @return the parsed date * @throws IllegalArgumentException if the date string or pattern array is null * @throws ParseException if none of the date patterns were suitable */ public static Date parseDate(String str, String[] parsePatterns) throws ParseException { if (str == null || parsePatterns == null) { throw new IllegalArgumentException("Date and Patterns must not be null"); } SimpleDateFormat parser = null; ParsePosition pos = new ParsePosition(0); for (int i = 0; i < parsePatterns.length; i++) { if (i == 0) { parser = new SimpleDateFormat(parsePatterns[0]); } else { parser.applyPattern(parsePatterns[i]); } pos.setIndex(0); Date date = parser.parse(str, pos); if (date != null && pos.getIndex() == str.length()) { return date; } } throw new ParseException("Unable to parse the date: " + str, -1); } }