Cron表达式解析类和时间相关操作工具类

/* * Copyright 2002-2017 the original author or authors. * * 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 com.xinhui.cronhelper; import java.util.ArrayList; import java.util.BitSet; import java.util.Calendar; import java.util.Collections; import java.util.Date; import java.util.GregorianCalendar; import java.util.List; import java.util.TimeZone; import org.springframework.util.StringUtils; /** * 定时器Cron解析帮助类，提供获取下一次执行时间 * * <p> * 示例: * <ul> * <li>"0 0 * * * *" = 每天每时0分0秒执行</li> * <li>"0 0 8-10 * * *" = 每天8点9点10点0分0秒执行</li> * <li>"0 0 6,19 * * *" = 每天6点19点0分0秒执行</li> * <li>"0 0/30 8-10 * * *" = 每天的8点到10点每30分钟执行</li> * <li>"0 0 9-17 * * MON-FRI" = 周末的9点到17点每小时执行</li> * <li>"0 0 0 25 12 ?" = 每年的12月25日0分0秒执行</li> * </ul> * */ public class CronHelper { private final String expression; private final TimeZone timeZone; private final BitSet months = new BitSet(12); private final BitSet daysOfMonth = new BitSet(31); private final BitSet daysOfWeek = new BitSet(7); private final BitSet hours = new BitSet(24); private final BitSet minutes = new BitSet(60); private final BitSet seconds = new BitSet(60); /** * 默认以当前系统所在的时区进行解析（本地为东8区时间，即北京时间） * * @param expression * 以空格分隔的时间字段表达式 */ public CronHelper(String expression) { this(expression, TimeZone.getDefault()); } /** * @param expression * 以空格分隔的时间字段表达式 * @param timeZone * 指定的时区 */ public CronHelper(String expression, TimeZone timeZone) { this.expression = expression; this.timeZone = timeZone; parse(expression); } private CronHelper(String expression, String[] fields) { this.expression = expression; this.timeZone = null; doParse(fields); } /** * * @return 获取Cron表达式 */ String getExpression() { return this.expression; } /** * 获取一个给定时间之后的，匹配cron的时间 * * @param date * @return cron下一次执行的时间 */ public Date next(Date date) { /* * 步骤: * * 1 从整秒开始（必要时毫秒进行四舍五入） * * 2 如果秒匹配则继续, 否则找下一个匹配: * 2.1 如果下一个匹配在下一分钟进行，则向前滚动 * * 3 如果分钟还是匹配的则继续进行, 否则找下一个匹配 * 3.1 如果下一个匹配在下一个小时，则向前滚 * 3.2 重置秒，转向步骤2 * * 4 如果小时还是匹配则继续进行, 否则找下一个匹配 * 4.1 如果下一个匹配在下一天，则向前滚, * 4.2 重置分钟和秒，转向步骤2 */ Calendar calendar = new GregorianCalendar(); calendar.setTimeZone(this.timeZone); calendar.setTime(date); // 重置清零毫秒数 calendar.set(Calendar.MILLISECOND, 0); long originalTimestamp = calendar.getTimeInMillis(); doNext(calendar, calendar.get(Calendar.YEAR)); if (calendar.getTimeInMillis() == originalTimestamp) { // 若当前时间即是触发时间 - 将时间调整到下一整秒，然后再试一次... calendar.add(Calendar.SECOND, 1); doNext(calendar, calendar.get(Calendar.YEAR)); } return calendar.getTime(); } /** * * @param calendar * 日历 * @param dot * 年份 */ private void doNext(Calendar calendar, int dot) { List<Integer> resets = new ArrayList<Integer>(); // 当前秒 int second = calendar.get(Calendar.SECOND); List<Integer> emptyList = Collections.emptyList(); int updateSecond = findNext(this.seconds, second, calendar, Calendar.SECOND, Calendar.MINUTE, emptyList); if (second == updateSecond) { resets.add(Calendar.SECOND); } // 当前分钟 int minute = calendar.get(Calendar.MINUTE); int updateMinute = findNext(this.minutes, minute, calendar, Calendar.MINUTE, Calendar.HOUR_OF_DAY, resets); if (minute == updateMinute) { resets.add(Calendar.MINUTE); } else { doNext(calendar, dot); } // 当前小时 int hour = calendar.get(Calendar.HOUR_OF_DAY); int updateHour = findNext(this.hours, hour, calendar, Calendar.HOUR_OF_DAY, Calendar.DAY_OF_WEEK, resets); if (hour == updateHour) { resets.add(Calendar.HOUR_OF_DAY); } else { doNext(calendar, dot); } // 当前是一周的第几天 int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK); // 当前是一月的第几天 int dayOfMonth = calendar.get(Calendar.DAY_OF_MONTH); int updateDayOfMonth = findNextDay(calendar, this.daysOfMonth, dayOfMonth, daysOfWeek, dayOfWeek, resets); if (dayOfMonth == updateDayOfMonth) { resets.add(Calendar.DAY_OF_MONTH); } else { doNext(calendar, dot); } // 当前月 int month = calendar.get(Calendar.MONTH); int updateMonth = findNext(this.months, month, calendar, Calendar.MONTH, Calendar.YEAR, resets); if (month != updateMonth) { if (calendar.get(Calendar.YEAR) - dot > 4) {//4年一瑞年，年份大于4年一周期都没找到为无效月份 throw new IllegalArgumentException("CRON表达式 \"" + this.expression + "\"中，无效的月份导致错误"); } doNext(calendar, dot); } } private int findNextDay(Calendar calendar, BitSet daysOfMonth, int dayOfMonth, BitSet daysOfWeek, int dayOfWeek, List<Integer> resets) { int count = 0; int max = 366; // DAY_OF_WEEK 的值在Calendar中从1 (Sunday)开始。但是在CRON表达式中从0开始，所以在这减去1 while ((!daysOfMonth.get(dayOfMonth) || !daysOfWeek.get(dayOfWeek - 1)) && count++ < max) { calendar.add(Calendar.DAY_OF_MONTH, 1); dayOfMonth = calendar.get(Calendar.DAY_OF_MONTH); dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK); reset(calendar, resets); } if (count >= max) { throw new IllegalArgumentException("表达式 \"" + this.expression + "\"中的天数超出366天范围"); } return dayOfMonth; } /** * 在提供的bits集合中搜索对应的值之后的下一个设置位的值，并重置Calendar。 * * @param bits * 字段的允许值 * @param value * 当前值 * @param calendar * Calendar按照bits集合滚动增加 * @param field * Calendar字段的增加（按照定义有效字段的静态常量值） * @param lowerOrders * 要重置的Calendar字段 * @return 下一个在calendar中的值 */ private int findNext(BitSet bits, int value, Calendar calendar, int field, int nextField, List<Integer> lowerOrders) { int nextValue = bits.nextSetBit(value); // 越界下一个字段加1，继续从头开始查找 if (nextValue == -1) { calendar.add(nextField, 1); reset(calendar, Collections.singletonList(field)); nextValue = bits.nextSetBit(0); } if (nextValue != value) { calendar.set(field, nextValue); reset(calendar, lowerOrders); } return nextValue; } /** * 将