Java tutorial
/** * 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. */ package org.apache.jena.atlas.lib; import java.util.Calendar; import java.util.Date; import java.util.GregorianCalendar; import org.apache.commons.lang3.time.FastDateFormat; public class DateTimeUtils { // Include timezone (even xsd:dates have timezones; Calendars have timezones) // NB in SimpleDateFormat != FastDateFormat // SimpleDateFormat does not format Calendars. // SimpleDateFormat has "X" for ISO format tmezones (+00:00) // FastDateFormat uses "ZZ" for this. private static final FastDateFormat dateTimeFmt_display = FastDateFormat.getInstance("yyyy/MM/dd HH:mm:ss z"); private static final FastDateFormat dateFmt_yyyymmdd = FastDateFormat.getInstance("yyyy-MM-ddZZ"); // For milliseconds == 0 private static final FastDateFormat dateTimeFmt_XSD_ms0 = FastDateFormat.getInstance("yyyy-MM-dd'T'HH:mm:ssZZ"); // For milliseconds != 0 private static final FastDateFormat dateTimeFmt_XSD_ms = FastDateFormat .getInstance("yyyy-MM-dd'T'HH:mm:ss.SSSZZ"); // For milliseconds == 0 private static final FastDateFormat timeFmt_XSD_ms0 = FastDateFormat.getInstance("HH:mm:ssZZ"); // For milliseconds != 0 private static final FastDateFormat timeFmt_XSD_ms = FastDateFormat.getInstance("HH:mm:ss.SSSZZ"); public static String nowAsXSDDateTimeString() { return calendarToXSDDateTimeString(new GregorianCalendar()); } public static String todayAsXSDDateString() { return calendarToXSDDateString(new GregorianCalendar()); } /** Return "now" as readable string (date in yyyy/MM/dd format) */ public static String nowAsString() { return nowAsString(dateTimeFmt_display); } public static String nowAsString(String formatString) { FastDateFormat df = FastDateFormat.getInstance(formatString); return df.format(new Date()); } public static String nowAsString(FastDateFormat dateFormat) { return dateFormat.format(new Date()); } private static boolean hasZeroMilliSeconds(Calendar cal) { return !cal.isSet(Calendar.MILLISECOND) || cal.get(Calendar.MILLISECOND) == 0; } // Canonical fom : if ms == 0, don't include in the string. public static String calendarToXSDDateTimeString(Calendar cal) { FastDateFormat fmt = hasZeroMilliSeconds(cal) ? dateTimeFmt_XSD_ms0 : dateTimeFmt_XSD_ms; return calendarToXSDString(cal, fmt); } public static String calendarToXSDDateString(Calendar cal) { return calendarToXSDString(cal, dateFmt_yyyymmdd); } // Canonical fom : if ms == 0, don't include in the string. public static String calendarToXSDTimeString(Calendar cal) { FastDateFormat fmt = hasZeroMilliSeconds(cal) ? timeFmt_XSD_ms0 : timeFmt_XSD_ms; return calendarToXSDString(cal, fmt); } private static String calendarToXSDString(Calendar cal, FastDateFormat fmt) { String lex = fmt.format(cal); // lex = lex + calcTimezone(cal) ; return lex; } // Not needed because of FastDateFormat // private static String calcTimezone(Calendar cal) { // Date date = cal.getTime() ; // TimeZone z = cal.getTimeZone() ; // int tz = z.getRawOffset() ; // // if ( z.inDaylightTime(date) ) { // int tzDst = z.getDSTSavings() ; // tz = tz + tzDst ; // } // // String sign = "+" ; // if ( tz < 0 ) { // sign = "-" ; // tz = -tz ; // } // // int tzH = tz / (60 * 60 * 1000) ; // Integer divide towards zero. // int tzM = (tz - tzH * 60 * 60 * 1000) / (60 * 1000) ; // // String tzH_str = Integer.toString(tzH) ; // String tzM_str = Integer.toString(tzM) ; // // if ( tzH < 10 ) // tzH_str = "0" + tzH_str ; // if ( tzM < 10 ) // tzM_str = "0" + tzM_str ; // return sign + tzH_str + ":" + tzM_str ; // } }