java8日期和时间的api以及精准控制两个时间点的间隔

java8日期和时间的api在java.time包下

java8所有的日期和时间的api都是不可变类以及确保线程安全

public static void main(String[] args) {
        LocalDate localDate = LocalDate.now();
        System.out.println(localDate);
        System.out.println(
                //2022
                "year:"+localDate.getYear()+
                        //MAY
                ",month:"+ localDate.getMonth()+
                        //5
                ",monthValue:"+localDate.getMonthValue()+
                        //CE
                ",Era:"+localDate.getEra()+
                        //8
                ",DayOfMonth:"+localDate.getDayOfMonth()+
                        //SUNDAY
                        ",DayOfWeek:"+localDate.getDayOfWeek()+
                        //128
                        ",DayOfYear:"+localDate.getDayOfYear());
        //2022-05-08
        LocalDate localDate1 = LocalDate.of(2022, 5, 8);
        System.out.println(localDate1);
        //只关注月份+天数(例如每年的生日)
        MonthDay monthDay = MonthDay.of(5, 8);
        MonthDay monthDay1 = MonthDay.from(localDate1);
        //true
        System.out.println(monthDay.equals(monthDay1));
        //关注时分秒13:16:36.373
        LocalTime localTime = LocalTime.now();
        System.out.println(localTime);
        //增加三小时20分钟 16:36:36.373
        LocalTime localTime1 = localTime.plusHours(3).plusMinutes(20);
        System.out.println(localTime1);

        //指定增加的数字和单位,注意:LocalDate没有时分秒,单位不可以是时分秒
        LocalDate localDate2 = localDate.plus(1, ChronoUnit.DAYS);
        System.out.println(localDate2);

        //localdata1:2022-05-08   localDate2:2022-05-09
        //判断localdata1是否在localDate2之后  false
        System.out.println(localDate1.isAfter(localDate2));
        //判断localdata1是否在localDate2之前  true
        System.out.println(localDate1.isBefore(localDate2));
        //判断localdata1是否和localDate2相等  false
        System.out.println(localDate1.isEqual(localDate2));

        // America/La_Paz, Antarctica/DumontDUrville, Asia/Taipei, Antarctica/South_Pole, Asia/Manila,
        // Asia/Bangkok, Africa/Dar_es_Salaam, Poland, Atlantic/Madeira, Antarctica/Palmer, America/Thunder_Bay,
        //......
        Set zoneIds = ZoneId.getAvailableZoneIds();

        //转为treeset使之有序
        Settreesets = new TreeSet(){
            {
                addAll(zoneIds);
            }
        };
        System.out.println(zoneIds);
    }

//计算起止时间不能超过12个月
    public static boolean computeTimeDiff01(long startTimeMillis, long endTimeMillis){
        //将startTimeMillis转为LocalDateTime
        LocalDateTime start = LocalDateTime.ofInstant(Instant.ofEpochMilli(startTimeMillis), ZoneId.systemDefault());
        //将endTimeMillis转为LocalDateTime并且月份减少12
        LocalDateTime end = LocalDateTime.ofInstant(Instant.ofEpochMilli(endTimeMillis), ZoneId.systemDefault())
                .minusMonths(12);
        //如果end和start相等,或者end在start之前,说明没有超过12个月
        //start:2022-05-01  end:2022-05-08  -->  end:2021-05-08
        //end在start之前即起止时间没有超过12个月
        return end.isEqual(start) || end.isBefore(start) ? false : true;
        
    }