Java tutorial
/** * Copyright (c) 2000-present Liferay, Inc. All rights reserved. * * This library is free software; you can redistribute it and/or modify it under * the terms of the GNU Lesser General Public License as published by the Free * Software Foundation; either version 2.1 of the License, or (at your option) * any later version. * * This library is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more * details. */ package com.liferay.portal.kernel.util; import com.liferay.petra.string.StringPool; import java.text.DateFormat; import java.text.Format; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Date; import java.util.GregorianCalendar; import java.util.HashMap; import java.util.Locale; import java.util.Map; import java.util.TimeZone; /** * @author Brian Wing Shun Chan */ public class DateUtil { public static final String ISO_8601_PATTERN = "yyyy-MM-dd'T'HH:mm:ssZ"; public static int compareTo(Date date1, Date date2) { if (date1 == date2) { return 0; } if (date1 == null) { return 1; } if (date2 == null) { return -1; } return Long.compare(date1.getTime(), date2.getTime()); } public static boolean equals(Date date1, Date date2) { if (compareTo(date1, date2) == 0) { return true; } return false; } public static String formatDate(String fromPattern, String dateString, Locale locale) throws ParseException { Date dateValue = parseDate(fromPattern, dateString, locale); Format dateFormat = FastDateFormatFactoryUtil.getDate(locale); return dateFormat.format(dateValue); } public static String getCurrentDate(String pattern, Locale locale) { return getDate(new Date(), pattern, locale); } public static String getCurrentDate(String pattern, Locale locale, TimeZone timeZone) { return getDate(new Date(), pattern, locale, timeZone); } public static String getDate(Date date, String pattern, Locale locale) { Format dateFormat = FastDateFormatFactoryUtil.getSimpleDateFormat(pattern, locale); return dateFormat.format(date); } public static String getDate(Date date, String pattern, Locale locale, TimeZone timeZone) { Format dateFormat = FastDateFormatFactoryUtil.getSimpleDateFormat(pattern, locale, timeZone); return dateFormat.format(date); } public static int getDaysBetween(Date date1, Date date2) { return getDaysBetween(date1, date2, null); } public static int getDaysBetween(Date date1, Date date2, TimeZone timeZone) { if (date1.after(date2)) { Date tempDate = date1; date1 = date2; date2 = tempDate; } Calendar startCal = null; Calendar endCal = null; int offsetDate1 = 0; int offsetDate2 = 0; if (timeZone == null) { startCal = new GregorianCalendar(); endCal = new GregorianCalendar(); } else { startCal = new GregorianCalendar(timeZone); endCal = new GregorianCalendar(timeZone); offsetDate1 = timeZone.getOffset(date1.getTime()); offsetDate2 = timeZone.getOffset(date2.getTime()); } startCal.setTime(date1); startCal.add(Calendar.MILLISECOND, offsetDate1); endCal.setTime(date2); endCal.add(Calendar.MILLISECOND, offsetDate2); int daysBetween = 0; while (CalendarUtil.beforeByDay(startCal.getTime(), endCal.getTime())) { startCal.add(Calendar.DAY_OF_MONTH, 1); daysBetween++; } return daysBetween; } public static DateFormat getISO8601Format() { return DateFormatFactoryUtil.getSimpleDateFormat(ISO_8601_PATTERN); } public static DateFormat getISOFormat() { return getISOFormat(StringPool.BLANK); } public static DateFormat getISOFormat(String text) { String pattern = StringPool.BLANK; if (text.length() == 8) { pattern = "yyyyMMdd"; } else if (text.length() == 12) { pattern = "yyyyMMddHHmm"; } else if (text.length() == 13) { pattern = "yyyyMMdd'T'HHmm"; } else if (text.length() == 14) { pattern = "yyyyMMddHHmmss"; } else if (text.length() == 15) { pattern = "yyyyMMdd'T'HHmmss"; } else if ((text.length() > 8) && (text.charAt(8) == 'T')) { pattern = "yyyyMMdd'T'HHmmssz"; } else { pattern = "yyyyMMddHHmmssz"; } return DateFormatFactoryUtil.getSimpleDateFormat(pattern); } public static DateFormat getUTCFormat() { return getUTCFormat(StringPool.BLANK); } public static DateFormat getUTCFormat(String text) { String pattern = StringPool.BLANK; if (text.length() == 8) { pattern = "yyyyMMdd"; } else if (text.length() == 12) { pattern = "yyyyMMddHHmm"; } else if (text.length() == 13) { pattern = "yyyyMMdd'T'HHmm"; } else if (text.length() == 14) { pattern = "yyyyMMddHHmmss"; } else if (text.length() == 15) { pattern = "yyyyMMdd'T'HHmmss"; } else { pattern = "yyyyMMdd'T'HHmmssz"; } return DateFormatFactoryUtil.getSimpleDateFormat(pattern, TimeZoneUtil.getTimeZone(StringPool.UTC)); } public static int getYear(Date date) { Calendar cal = Calendar.getInstance(); cal.setTime(date); return cal.get(Calendar.YEAR); } public static boolean isFormatAmPm(Locale locale) { Boolean formatAmPm = _formatAmPmMap.get(locale); if (formatAmPm == null) { SimpleDateFormat simpleDateFormat = (SimpleDateFormat) DateFormat.getTimeInstance(DateFormat.SHORT, locale); String pattern = simpleDateFormat.toPattern(); formatAmPm = pattern.contains("a"); _formatAmPmMap.put(locale, formatAmPm); } return formatAmPm; } public static Date newDate() { return new Date(); } public static Date newDate(long date) { return new Date(date); } public static long newTime() { Date date = new Date(); return date.getTime(); } public static Date parseDate(String dateString, Locale locale) throws ParseException { return parseDate(null, dateString, locale); } public static Date parseDate(String pattern, String dateString, Locale locale) throws ParseException { DateFormat dateFormat = null; if (Validator.isNull(pattern)) { dateFormat = DateFormat.getDateInstance(DateFormat.SHORT, locale); } else { dateFormat = DateFormatFactoryUtil.getSimpleDateFormat(pattern, locale); } return dateFormat.parse(dateString); } private static final Map<Locale, Boolean> _formatAmPmMap = new HashMap<>(); }