Java tutorial
/** * Copyright 2014 David L. Whitehurst * * Licensed 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. * */ package org.musicrecital.util; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.musicrecital.Constants; import org.springframework.context.i18n.LocaleContextHolder; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Date; import java.util.GregorianCalendar; import java.util.Locale; import java.util.MissingResourceException; import java.util.ResourceBundle; /** * Date Utility Class used to convert Strings to Dates and Timestamps * * @author <a href="mailto:matt@raibledesigns.com">Matt Raible</a> * Modified by <a href="mailto:dan@getrolling.com">Dan Kibler </a> * to correct time pattern. Minutes should be mm not MM (MM is month). */ public final class DateUtil { private static Log log = LogFactory.getLog(DateUtil.class); private static final String TIME_PATTERN = "HH:mm"; /** * Checkstyle rule: utility classes should not have public constructor */ private DateUtil() { } /** * Return default datePattern (MM/dd/yyyy) * * @return a string representing the date pattern on the UI */ public static String getDatePattern() { Locale locale = LocaleContextHolder.getLocale(); String defaultDatePattern; try { defaultDatePattern = ResourceBundle.getBundle(Constants.BUNDLE_KEY, locale).getString("date.format"); } catch (MissingResourceException mse) { defaultDatePattern = "MM/dd/yyyy"; } return defaultDatePattern; } public static String getDateTimePattern() { return DateUtil.getDatePattern() + " HH:mm:ss.S"; } /** * This method attempts to convert an Oracle-formatted date * in the form dd-MMM-yyyy to mm/dd/yyyy. * * @param aDate date from database as a string * @return formatted string for the ui */ public static String getDate(Date aDate) { SimpleDateFormat df; String returnValue = ""; if (aDate != null) { df = new SimpleDateFormat(getDatePattern()); returnValue = df.format(aDate); } return (returnValue); } /** * This method generates a string representation of a date/time * in the format you specify on input * * @param aMask the date pattern the string is in * @param strDate a string representation of a date * @return a converted Date object * @throws ParseException when String doesn't match the expected format * @see java.text.SimpleDateFormat */ public static Date convertStringToDate(String aMask, String strDate) throws ParseException { SimpleDateFormat df; Date date; df = new SimpleDateFormat(aMask); if (log.isDebugEnabled()) { log.debug("converting '" + strDate + "' to date with mask '" + aMask + "'"); } try { date = df.parse(strDate); } catch (ParseException pe) { //log.error("ParseException: " + pe); throw new ParseException(pe.getMessage(), pe.getErrorOffset()); } return (date); } /** * This method returns the current date time in the format: * MM/dd/yyyy HH:MM a * * @param theTime the current time * @return the current date/time */ public static String getTimeNow(Date theTime) { return getDateTime(TIME_PATTERN, theTime); } /** * This method returns the current date in the format: MM/dd/yyyy * * @return the current date * @throws ParseException when String doesn't match the expected format */ public static Calendar getToday() throws ParseException { Date today = new Date(); SimpleDateFormat df = new SimpleDateFormat(getDatePattern()); // This seems like quite a hack (date -> string -> date), // but it works ;-) String todayAsString = df.format(today); Calendar cal = new GregorianCalendar(); cal.setTime(convertStringToDate(todayAsString)); return cal; } /** * This method generates a string representation of a date's date/time * in the format you specify on input * * @param aMask the date pattern the string is in * @param aDate a date object * @return a formatted string representation of the date * @see java.text.SimpleDateFormat */ public static String getDateTime(String aMask, Date aDate) { SimpleDateFormat df = null; String returnValue = ""; if (aDate == null) { log.warn("aDate is null!"); } else { df = new SimpleDateFormat(aMask); returnValue = df.format(aDate); } return (returnValue); } /** * This method generates a string representation of a date based * on the System Property 'dateFormat' * in the format you specify on input * * @param aDate A date to convert * @return a string representation of the date */ public static String convertDateToString(Date aDate) { return getDateTime(getDatePattern(), aDate); } /** * This method converts a String to a date using the datePattern * * @param strDate the date to convert (in format MM/dd/yyyy) * @return a date object * @throws ParseException when String doesn't match the expected format */ public static Date convertStringToDate(final String strDate) throws ParseException { return convertStringToDate(getDatePattern(), strDate); } }