LocalDateTime工具类：根据当前、周、月、季度、半年、年等维度获取时间

布满荆棘的人生 2023-10-04 12:36 14阅读 0赞

1. 简介

Java8提供了全新的日期处理包(java.time.\*)，根据Java8日期新特性封装日期时间工具类**LocalDateTimeUtils**。

2. 相关博客

[Java 8 新特性：日期处理][Java 8]

3. 工具类方法目录

<table> 
 <thead> 
  <tr> 
   <th>说明</th> 
   <th>方法名称</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>当前时间</td> 
   <td>LocalDateTimeUtils.now()</td> 
  </tr> 
  <tr> 
   <td>Date 转 LocalDateTime</td> 
   <td>LocalDateTimeUtils.convert(new Date()));</td> 
  </tr> 
  <tr> 
   <td>LocalDateTime 转 Date</td> 
   <td>LocalDateTimeUtils.convert(LocalDateTime.now()));</td> 
  </tr> 
  <tr> 
   <td>今天开始时间</td> 
   <td>LocalDateTimeUtils.todayStartTime()</td> 
  </tr> 
  <tr> 
   <td>今天结束时间</td> 
   <td>LocalDateTimeUtils.todayEndTime()</td> 
  </tr> 
  <tr> 
   <td>昨天开始时间</td> 
   <td>LocalDateTimeUtils.yesterdayStartTime()</td> 
  </tr> 
  <tr> 
   <td>昨天结束时间</td> 
   <td>LocalDateTimeUtils.yesterdayEndTime()</td> 
  </tr> 
  <tr> 
   <td>最近7天开始时间</td> 
   <td>LocalDateTimeUtils.last7DaysStartTime()</td> 
  </tr> 
  <tr> 
   <td>最近7天结束时间</td> 
   <td>LocalDateTimeUtils.last7DaysEndTime()</td> 
  </tr> 
  <tr> 
   <td>最近30天开始时间</td> 
   <td>LocalDateTimeUtils.last30DaysStartTime()</td> 
  </tr> 
  <tr> 
   <td>最近30天天结束时间</td> 
   <td>LocalDateTimeUtils.last30DaysEndTime()</td> 
  </tr> 
  <tr> 
   <td>最近一年开始时间</td> 
   <td>LocalDateTimeUtils.last1YearStartTime()</td> 
  </tr> 
  <tr> 
   <td>最近一年结束时间</td> 
   <td>LocalDateTimeUtils.last1YearEndTime()</td> 
  </tr> 
  <tr> 
   <td>本周开始时间</td> 
   <td>LocalDateTimeUtils.weekStartTime()</td> 
  </tr> 
  <tr> 
   <td>本周结束时间</td> 
   <td>LocalDateTimeUtils.weekEndTime()</td> 
  </tr> 
  <tr> 
   <td>本月开始时间</td> 
   <td>LocalDateTimeUtils.monthStartTime()</td> 
  </tr> 
  <tr> 
   <td>本月结束时间</td> 
   <td>LocalDateTimeUtils.monthEndTime()</td> 
  </tr> 
  <tr> 
   <td>本季度开始时间</td> 
   <td>LocalDateTimeUtils.quarterStartTime()</td> 
  </tr> 
  <tr> 
   <td>本季度结束时间</td> 
   <td>LocalDateTimeUtils.quarterEndTime()</td> 
  </tr> 
  <tr> 
   <td>本半年开始时间</td> 
   <td>LocalDateTimeUtils.halfYearStartTime()</td> 
  </tr> 
  <tr> 
   <td>本半年结束时间</td> 
   <td>LocalDateTimeUtils.halfYearEndTime()</td> 
  </tr> 
  <tr> 
   <td>本年开始时间</td> 
   <td>LocalDateTimeUtils.yearStartTime()</td> 
  </tr> 
  <tr> 
   <td>本年结束时间</td> 
   <td>LocalDateTimeUtils.yearEndTime()</td> 
  </tr> 
  <tr> 
   <td>上周开始时间</td> 
   <td>LocalDateTimeUtils.lastWeekStartTime()</td> 
  </tr> 
  <tr> 
   <td>上周结束时间</td> 
   <td>LocalDateTimeUtils.lastWeekEndTime()</td> 
  </tr> 
  <tr> 
   <td>上月开始时间</td> 
   <td>LocalDateTimeUtils.lastMonthStartTime()</td> 
  </tr> 
  <tr> 
   <td>上月结束时间</td> 
   <td>LocalDateTimeUtils.lastMonthEndTime()</td> 
  </tr> 
  <tr> 
   <td>上季度开始时间</td> 
   <td>LocalDateTimeUtils.lastQuarterStartTime()</td> 
  </tr> 
  <tr> 
   <td>上季度结束时间</td> 
   <td>LocalDateTimeUtils.lastQuarterEndTime()</td> 
  </tr> 
  <tr> 
   <td>上半年开始时间</td> 
   <td>LocalDateTimeUtils.lastHalfYearStartTime()</td> 
  </tr> 
  <tr> 
   <td>上半年结束时间</td> 
   <td>LocalDateTimeUtils.lastHalfYearEndTime()</td> 
  </tr> 
  <tr> 
   <td>上一年开始时间</td> 
   <td>LocalDateTimeUtils.lastYearStartTime()</td> 
  </tr> 
  <tr> 
   <td>上一年结束时间</td> 
   <td>LocalDateTimeUtils.lastYearEndTime()</td> 
  </tr> 
  <tr> 
   <td>下周开始时间</td> 
   <td>LocalDateTimeUtils.nextWeekStartTime()</td> 
  </tr> 
  <tr> 
   <td>下周结束时间</td> 
   <td>LocalDateTimeUtils.nextWeekEndTime()</td> 
  </tr> 
  <tr> 
   <td>下月开始时间</td> 
   <td>LocalDateTimeUtils.nextMonthStartTime()</td> 
  </tr> 
  <tr> 
   <td>下月结束时间</td> 
   <td>LocalDateTimeUtils.nextMonthEndTime()</td> 
  </tr> 
  <tr> 
   <td>下季度开始时间</td> 
   <td>LocalDateTimeUtils.nextQuarterStartTime()</td> 
  </tr> 
  <tr> 
   <td>下季度结束时间</td> 
   <td>LocalDateTimeUtils.nextQuarterEndTime()</td> 
  </tr> 
  <tr> 
   <td>下半年开始时间</td> 
   <td>LocalDateTimeUtils.nextHalfYearStartTime()</td> 
  </tr> 
  <tr> 
   <td>下半年结束时间</td> 
   <td>LocalDateTimeUtils.nextHalfYearEndTime()</td> 
  </tr> 
  <tr> 
   <td>下一年开始时间</td> 
   <td>LocalDateTimeUtils.nextYearStartTime()</td> 
  </tr> 
  <tr> 
   <td>下一年结束时间</td> 
   <td>LocalDateTimeUtils.nextYearEndTime()</td> 
  </tr> 
 </tbody> 
</table>

4. 示例代码

import java.time.*;
    import java.time.temporal.ChronoUnit;
    import java.time.temporal.TemporalAdjusters;
    import java.util.Date;
    
    /**
     * LocalDateTime工具类
     *
     * @author CL
     */
    public class LocalDateTimeUtils {
    
        /**
         * 当前时间
         *
         * @return
         */
        public static LocalDateTime now() {
            return LocalDateTime.now();
        }
    
        /**
         * Date 转 LocalDateTime
         *
         * @return
         */
        public static LocalDateTime convert(Date date) {
            return LocalDateTime.ofInstant(Instant.ofEpochMilli(date.getTime()), ZoneId.systemDefault());
        }
    
        /**
         * LocalDateTime 转 Date
         *
         * @return
         */
        public static Date convert(LocalDateTime localDateTime) {
            return Date.from(localDateTime.atZone(ZoneId.systemDefault()).toInstant());
        }
    
        /**
         * 今天开始时间
         *
         * @return
         */
        public static LocalDateTime todayStartTime() {
            return LocalDateTime.of(LocalDate.now(), LocalTime.MIN);
        }
    
        /**
         * 今天结束时间
         *
         * @return
         */
        public static LocalDateTime todayEndTime() {
            return LocalDateTime.of(LocalDate.now(), LocalTime.MAX);
        }
    
        /**
         * 昨天开始时间
         *
         * @return
         */
        public static LocalDateTime yesterdayStartTime() {
            return LocalDateTime.of(LocalDate.now().minus(1L, ChronoUnit.DAYS), LocalTime.MIN);
        }
    
        /**
         * 昨天结束时间
         *
         * @return
         */
        public static LocalDateTime yesterdayEndTime() {
            return LocalDateTime.of(LocalDate.now().minus(1L, ChronoUnit.DAYS), LocalTime.MAX);
        }
    
        /**
         * 最近7天开始时间
         *
         * @return
         */
        public static LocalDateTime last7DaysStartTime() {
            return LocalDateTime.of(LocalDate.now().minus(6L, ChronoUnit.DAYS), LocalTime.MIN);
        }
    
        /**
         * 最近7天结束时间
         *
         * @return
         */
        public static LocalDateTime last7DaysEndTime() {
            return LocalDateTime.of(LocalDate.now(), LocalTime.MAX);
        }
    
        /**
         * 最近30天开始时间
         *
         * @return
         */
        public static LocalDateTime last30DaysStartTime() {
            return LocalDateTime.of(LocalDate.now().minus(29L, ChronoUnit.DAYS), LocalTime.MIN);
        }
    
        /**
         * 最近30天结束时间
         *
         * @return
         */
        public static LocalDateTime last30DaysEndTime() {
            return LocalDateTime.of(LocalDate.now(), LocalTime.MAX);
        }
    
        /**
         * 最近一年开始时间
         *
         * @return
         */
        public static LocalDateTime last1YearStartTime() {
            return LocalDateTime.of(LocalDate.now().minus(1L, ChronoUnit.YEARS).plus(1L, ChronoUnit.DAYS), LocalTime.MIN);
        }
    
        /**
         * 最近一年结束时间
         *
         * @return
         */
        public static LocalDateTime last1YearEndTime() {
            return LocalDateTime.of(LocalDate.now(), LocalTime.MAX);
        }
    
        /**
         * 本周开始时间
         *
         * @return
         */
        public static LocalDateTime weekStartTime() {
            LocalDate now = LocalDate.now();
            return LocalDateTime.of(now.minusDays(now.getDayOfWeek().getValue() - 1), LocalTime.MIN);
        }
    
        /**
         * 本周结束时间
         *
         * @return
         */
        public static LocalDateTime weekEndTime() {
            LocalDate now = LocalDate.now();
            return LocalDateTime.of(now.plusDays(7 - now.getDayOfWeek().getValue()), LocalTime.MAX);
        }
    
        /**
         * 本月开始时间
         *
         * @return
         */
        public static LocalDateTime monthStartTime() {
            return LocalDateTime.of(LocalDate.now().with(TemporalAdjusters.firstDayOfMonth()), LocalTime.MIN);
        }
    
        /**
         * 本月结束时间
         *
         * @return
         */
        public static LocalDateTime monthEndTime() {
            return LocalDateTime.of(LocalDate.now().with(TemporalAdjusters.lastDayOfMonth()), LocalTime.MAX);
        }
    
        /**
         * 本季度开始时间
         *
         * @return
         */
        public static LocalDateTime quarterStartTime() {
            LocalDate now = LocalDate.now();
            Month month = Month.of(now.getMonth().firstMonthOfQuarter().getValue());
            return LocalDateTime.of(LocalDate.of(now.getYear(), month, 1), LocalTime.MIN);
        }
    
        /**
         * 本季度结束时间
         *
         * @return
         */
        public static LocalDateTime quarterEndTime() {
            LocalDate now = LocalDate.now();
            Month month = Month.of(now.getMonth().firstMonthOfQuarter().getValue()).plus(2L);
            return LocalDateTime.of(LocalDate.of(now.getYear(), month, month.length(now.isLeapYear())), LocalTime.MAX);
        }
    
        /**
         * 本半年开始时间
         *
         * @return
         */
        public static LocalDateTime halfYearStartTime() {
            LocalDate now = LocalDate.now();
            Month month = (now.getMonthValue() > 6) ? Month.JULY : Month.JANUARY;
            return LocalDateTime.of(LocalDate.of(now.getYear(), month, 1), LocalTime.MIN);
        }
    
        /**
         * 本半年结束时间
         *
         * @return
         */
        public static LocalDateTime halfYearEndTime() {
            LocalDate now = LocalDate.now();
            Month month = (now.getMonthValue() > 6) ? Month.DECEMBER : Month.JUNE;
            return LocalDateTime.of(LocalDate.of(now.getYear(), month, month.length(now.isLeapYear())), LocalTime.MAX);
        }
    
        /**
         * 本年开始时间
         *
         * @return
         */
        public static LocalDateTime yearStartTime() {
            return LocalDateTime.of(LocalDate.now().with(TemporalAdjusters.firstDayOfYear()), LocalTime.MIN);
        }
    
        /**
         * 本年结束时间
         *
         * @return
         */
        public static LocalDateTime yearEndTime() {
            return LocalDateTime.of(LocalDate.now().with(TemporalAdjusters.lastDayOfYear()), LocalTime.MAX);
        }
    
        /**
         * 上周开始时间
         *
         * @return
         */
        public static LocalDateTime lastWeekStartTime() {
            LocalDate lastWeek = LocalDate.now().minus(1L, ChronoUnit.WEEKS);
            return LocalDateTime.of(lastWeek.minusDays(lastWeek.getDayOfWeek().getValue() - 1), LocalTime.MIN);
        }
    
        /**
         * 上周结束时间
         *
         * @return
         */
        public static LocalDateTime lastWeekEndTime() {
            LocalDate lastWeek = LocalDate.now().minus(1L, ChronoUnit.WEEKS);
            return LocalDateTime.of(lastWeek.plusDays(7 - lastWeek.getDayOfWeek().getValue()), LocalTime.MAX);
        }
    
        /**
         * 上月开始时间
         *
         * @return
         */
        public static LocalDateTime lastMonthStartTime() {
            return LocalDateTime.of(LocalDate.now().minus(1L, ChronoUnit.MONTHS).with(TemporalAdjusters.firstDayOfMonth()), LocalTime.MIN);
        }
    
        /**
         * 上月结束时间
         *
         * @return
         */
        public static LocalDateTime lastMonthEndTime() {
            return LocalDateTime.of(LocalDate.now().minus(1L, ChronoUnit.MONTHS).with(TemporalAdjusters.lastDayOfMonth()), LocalTime.MAX);
        }
    
        /**
         * 上季度开始时间
         *
         * @return
         */
        public static LocalDateTime lastQuarterStartTime() {
            LocalDate now = LocalDate.now();
            Month firstMonthOfQuarter = Month.of(now.getMonth().firstMonthOfQuarter().getValue());
            Month firstMonthOfLastQuarter = firstMonthOfQuarter.minus(3L);
            int yearOfLastQuarter = firstMonthOfQuarter.getValue() < 4 ? now.getYear() - 1 : now.getYear();
            return LocalDateTime.of(LocalDate.of(yearOfLastQuarter, firstMonthOfLastQuarter, 1), LocalTime.MIN);
        }
    
        /**
         * 上季度结束时间
         *
         * @return
         */
        public static LocalDateTime lastQuarterEndTime() {
            LocalDate now = LocalDate.now();
            Month firstMonthOfQuarter = Month.of(now.getMonth().firstMonthOfQuarter().getValue());
            Month firstMonthOfLastQuarter = firstMonthOfQuarter.minus(1L);
            int yearOfLastQuarter = firstMonthOfQuarter.getValue() < 4 ? now.getYear() - 1 : now.getYear();
            return LocalDateTime.of(LocalDate.of(yearOfLastQuarter, firstMonthOfLastQuarter, firstMonthOfLastQuarter.maxLength()), LocalTime.MAX);
        }
    
        /**
         * 上半年开始时间
         *
         * @return
         */
        public static LocalDateTime lastHalfYearStartTime() {
            LocalDate now = LocalDate.now();
            int lastHalfYear = (now.getMonthValue() > 6) ? now.getYear() : now.getYear() - 1;
            Month firstMonthOfLastHalfYear = (now.getMonthValue() > 6) ? Month.JANUARY : Month.JULY;
            return LocalDateTime.of(LocalDate.of(lastHalfYear, firstMonthOfLastHalfYear, 1), LocalTime.MIN);
        }
    
        /**
         * 上半年结束时间
         *
         * @return
         */
        public static LocalDateTime lastHalfYearEndTime() {
            LocalDate now = LocalDate.now();
            int lastHalfYear = (now.getMonthValue() > 6) ? now.getYear() : now.getYear() - 1;
            Month lastMonthOfLastHalfYear = (now.getMonthValue() > 6) ? Month.JUNE : Month.DECEMBER;
            return LocalDateTime.of(LocalDate.of(lastHalfYear, lastMonthOfLastHalfYear, lastMonthOfLastHalfYear.maxLength()), LocalTime.MAX);
        }
    
        /**
         * 上一年开始时间
         *
         * @return
         */
        public static LocalDateTime lastYearStartTime() {
            return LocalDateTime.of(LocalDate.now().minus(1L, ChronoUnit.YEARS).with(TemporalAdjusters.firstDayOfYear()), LocalTime.MIN);
        }
    
        /**
         * 上一年结束时间
         *
         * @return
         */
        public static LocalDateTime lastYearEndTime() {
            return LocalDateTime.of(LocalDate.now().minus(1L, ChronoUnit.YEARS).with(TemporalAdjusters.lastDayOfYear()), LocalTime.MAX);
        }
    
        /**
         * 下周开始时间
         *
         * @return
         */
        public static LocalDateTime nextWeekStartTime() {
            LocalDate nextWeek = LocalDate.now().plus(1L, ChronoUnit.WEEKS);
            return LocalDateTime.of(nextWeek.minusDays(nextWeek.getDayOfWeek().getValue() - 1), LocalTime.MIN);
        }
    
        /**
         * 下周结束时间
         *
         * @return
         */
        public static LocalDateTime nextWeekEndTime() {
            LocalDate nextWeek = LocalDate.now().plus(1L, ChronoUnit.WEEKS);
            return LocalDateTime.of(nextWeek.plusDays(7 - nextWeek.getDayOfWeek().getValue()), LocalTime.MAX);
        }
    
        /**
         * 下月开始时间
         *
         * @return
         */
        public static LocalDateTime nextMonthStartTime() {
            return LocalDateTime.of(LocalDate.now().plus(1L, ChronoUnit.MONTHS).with(TemporalAdjusters.firstDayOfMonth()), LocalTime.MIN);
        }
    
        /**
         * 下月结束时间
         *
         * @return
         */
        public static LocalDateTime nextMonthEndTime() {
            return LocalDateTime.of(LocalDate.now().plus(1L, ChronoUnit.MONTHS).with(TemporalAdjusters.lastDayOfMonth()), LocalTime.MAX);
        }
    
        /**
         * 下季度开始时间
         *
         * @return
         */
        public static LocalDateTime nextQuarterStartTime() {
            LocalDate now = LocalDate.now();
            Month firstMonthOfQuarter = Month.of(now.getMonth().firstMonthOfQuarter().getValue());
            Month firstMonthOfNextQuarter = firstMonthOfQuarter.plus(3L);
            int yearOfNextQuarter = firstMonthOfQuarter.getValue() > 9 ? now.getYear() + 1 : now.getYear();
            return LocalDateTime.of(LocalDate.of(yearOfNextQuarter, firstMonthOfNextQuarter, 1), LocalTime.MIN);
        }
    
        /**
         * 下季度结束时间
         *
         * @return
         */
        public static LocalDateTime nextQuarterEndTime() {
            LocalDate now = LocalDate.now();
            Month firstMonthOfQuarter = Month.of(now.getMonth().firstMonthOfQuarter().getValue());
            Month firstMonthOfNextQuarter = firstMonthOfQuarter.plus(5L);
            int yearOfNextQuarter = firstMonthOfQuarter.getValue() > 9 ? now.getYear() + 1 : now.getYear();
            return LocalDateTime.of(LocalDate.of(yearOfNextQuarter, firstMonthOfNextQuarter, firstMonthOfNextQuarter.maxLength()), LocalTime.MAX);
        }
    
        /**
         * 上半年开始时间
         *
         * @return
         */
        public static LocalDateTime nextHalfYearStartTime() {
            LocalDate now = LocalDate.now();
            int nextHalfYear = (now.getMonthValue() > 6) ? now.getYear() + 1 : now.getYear();
            Month firstMonthOfNextHalfYear = (now.getMonthValue() > 6) ? Month.JANUARY : Month.JULY;
            return LocalDateTime.of(LocalDate.of(nextHalfYear, firstMonthOfNextHalfYear, 1), LocalTime.MIN);
        }
    
        /**
         * 上半年结束时间
         *
         * @return
         */
        public static LocalDateTime nextHalfYearEndTime() {
            LocalDate now = LocalDate.now();
            int lastHalfYear = (now.getMonthValue() > 6) ? now.getYear() + 1 : now.getYear();
            Month lastMonthOfNextHalfYear = (now.getMonthValue() > 6) ? Month.JUNE : Month.DECEMBER;
            return LocalDateTime.of(LocalDate.of(lastHalfYear, lastMonthOfNextHalfYear, lastMonthOfNextHalfYear.maxLength()), LocalTime.MAX);
        }
    
        /**
         * 下一年开始时间
         *
         * @return
         */
        public static LocalDateTime nextYearStartTime() {
            return LocalDateTime.of(LocalDate.now().plus(1L, ChronoUnit.YEARS).with(TemporalAdjusters.firstDayOfYear()), LocalTime.MIN);
        }
    
        /**
         * 下一年结束时间
         *
         * @return
         */
        public static LocalDateTime nextYearEndTime() {
            return LocalDateTime.of(LocalDate.now().plus(1L, ChronoUnit.YEARS).with(TemporalAdjusters.lastDayOfYear()), LocalTime.MAX);
        }
    
        public static void main(String[] args) {
            System.out.println("当前时间：" + now());
            System.out.println("Date 转 LocalDateTime：" + convert(new Date()));
            System.out.println("LocalDateTime 转 Date：" + convert(LocalDateTime.now()));
            System.out.println("今天开始时间：" + todayStartTime());
            System.out.println("今天结束时间：" + todayEndTime());
            System.out.println("昨天开始时间：" + yesterdayStartTime());
            System.out.println("昨天结束时间：" + yesterdayEndTime());
            System.out.println("最近7天开始时间：" + last7DaysStartTime());
            System.out.println("最近7天结束时间：" + last7DaysEndTime());
            System.out.println("最近30天开始时间：" + last30DaysStartTime());
            System.out.println("最近30天天结束时间：" + last30DaysEndTime());
            System.out.println("最近一年开始时间：" + last1YearStartTime());
            System.out.println("最近一年结束时间：" + last1YearEndTime());
            System.out.println("本周开始时间：" + weekStartTime());
            System.out.println("本周结束时间：" + weekEndTime());
            System.out.println("本月开始时间：" + monthStartTime());
            System.out.println("本月结束时间：" + monthEndTime());
            System.out.println("本季度开始时间：" + quarterStartTime());
            System.out.println("本季度结束时间：" + quarterEndTime());
            System.out.println("本半年开始时间：" + halfYearStartTime());
            System.out.println("本半年结束时间：" + halfYearEndTime());
            System.out.println("本年开始时间：" + yearStartTime());
            System.out.println("本年结束时间：" + yearEndTime());
            System.out.println("上周开始时间：" + lastWeekStartTime());
            System.out.println("上周结束时间：" + lastWeekEndTime());
            System.out.println("上月开始时间：" + lastMonthStartTime());
            System.out.println("上月结束时间：" + lastMonthEndTime());
            System.out.println("上季度开始时间：" + lastQuarterStartTime());
            System.out.println("上季度结束时间：" + lastQuarterEndTime());
            System.out.println("上半年开始时间：" + lastHalfYearStartTime());
            System.out.println("上半年结束时间：" + lastHalfYearEndTime());
            System.out.println("上一年开始时间：" + lastYearStartTime());
            System.out.println("上一年结束时间：" + lastYearEndTime());
            System.out.println("下周开始时间：" + nextWeekStartTime());
            System.out.println("下周结束时间：" + nextWeekEndTime());
            System.out.println("下月开始时间：" + nextMonthStartTime());
            System.out.println("下月结束时间：" + nextMonthEndTime());
            System.out.println("下季度开始时间：" + nextQuarterStartTime());
            System.out.println("下季度结束时间：" + nextQuarterEndTime());
            System.out.println("下半年开始时间：" + nextHalfYearStartTime());
            System.out.println("下半年结束时间：" + nextHalfYearEndTime());
            System.out.println("下一年开始时间：" + nextYearStartTime());
            System.out.println("下一年结束时间：" + nextYearEndTime());
        }
    
    }

[Java 8]: https://www.cnblogs.com/cao-lei/p/12937590.html