JAVA基础知识之Time总结 javatimejava基础

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//截取到天，小时 System.out.println(LocalDateTime.now().truncatedTo(ChronoUnit.DAYS)); System.out.println(LocalDateTime.now().truncatedTo(ChronoUnit.HOURS)); //输出 2020-05-06T00:00 2020-05-06T13:00 //设置小时为14点 System.out.println(LocalDateTime.now().withHour(14)); //减去12天 System.out.println(LocalDateTime.now().minusDays(12)); //增加12小时 System.out.println(LocalDateTime.now().plusHours(12)); //设定0时区时间，截取到整日，设定12点 OffsetDateTime.now(ZoneOffset.of("+00:00")).truncatedTo(ChronoUnit.DAYS).withHour(12) //获取上海时区的时间 OffsetDateTime.now(ZoneId.of("Asia/Shanghai"))//实间转换 LocalDate loc = LocalDate.parse("2020-01-02"); System.out.println(loc); DateTimeFormatter usDateformatter = DateTimeFormatter.ofPattern("MM-dd-yyyy"); System.out.println(usDateformatter.format(loc)); //输出 2020-01-02 01-02-2020 //当parse的格式不是本地时间格式是，需要通过对应的formatter格式 LocalDate newDate = LocalDate.parse("07-04-2020",usDateformatter); System.out.println(newDate); //输出 2020-07-04

旧版本time类型Calendar，Date

Calendar cal = Calendar.getInstance(); cal.set(2020,1,26); Date date = cal.getTime(); System.out.println(date); //输出 Wed Feb 26 22:01:51 CST 2020 cal.add(Calendar.DAY_OF_MONTH,7); System.out.println(cal.getTime()); //输出 Wed Mar 04 22:01:51 CST 2020

新Time类型Instant是不可改变的

System.out.println(Instant.MIN); System.out.println(Instant.now()); System.out.println(Instant.MAX); //输出 -1000000000-01-01T00:00:00Z 2020-05-17T14:10:23.739Z +1000000000-12-31T23:59:59.999999999Z

Duration，包括toDays()，toHours(),toMinutes(),toNanos()等方法,minus()减去，plus增加，multipliedBy乘以

Instant start = Instant.now(); Thread.sleep(1); Instant end = Instant.now(); Duration duration = Duration.between(start,end); long millionSeconds = duration.toMillis(); System.out.println(millionSeconds); //输出 1

LocalDate
【JAVA基础知识之Time总结】TemporalAdjusters包括的方法：firstDayOfMonth，lastDayOfMonth，firstDayOfYear，lastDayOfYear，firstDayOfNextMonth，firstDayOfNextYear
firstInMonth(DayOfWeek.SUNDAY,lastInMonth(DayOfWeek.SUNDAY),dayOfWeekInMonth(2,DayOfWeek.SUNDAY)
next(DayOfWeek.SUNDAY),nextOrSame(DayOfWeek.SUNDAY),previous(DayOfWeek.SUNDAY),previousOrSame(DayOfWeek.SUNDAY)

LocalDate now = LocalDate.now(); LocalDate dateOfBirth = LocalDate.of(1987, Month.NOVEMBER, 23); System.out.println(dateOfBirth); System.out.println(now); //输出 1987-11-23 2020-05-18 Period p = dateOfBirth.until(now); System.out.println("Years:"+p.getYears()); //输出 Years:32 Long days = dateOfBirth.until(now,ChronoUnit.DAYS); System.out.println("Days:"+days); //输出 Days:11865 //其中的month差距只是余数，不是和上面的一样共计多少个月，而是除去整年后差的月数 System.out.println(p.get(ChronoUnit.YEARS)); System.out.println(p.get(ChronoUnit.MONTHS)); //输出 32 5 LocalDate nextSunday = LocalDate.now().with(TemporalAdjusters.next(DayOfWeek.SUNDAY)); System.out.println(nextSunday); //输出 2020-05-24

LocalTime

LocalTime localTime = LocalTime.now(); System.out.println(localTime); System.out.println(localTime.plusHours(8)); System.out.println(LocalTime.of(20,10)); //输出 20:28:59.823 04:30:25.367 20:10

ZonedDateTime

Set allZoneIds = ZoneId.getAvailableZoneIds(); for(String zoneId:allZoneIds){ if(zoneId.contains("America")){ System.out.println(zoneId); } } //输出很多暂时忽略 ZoneId ukTZ = ZoneId.of("Asia/Shanghai"); System.out.println(ukTZ); ZonedDateTime currentMetting = ZonedDateTime.of(LocalDate.of(2020,Month.JUNE,18), LocalTime.of(10,0),ZoneId.of("Asia/Shanghai")); ZonedDateTime nextMetting = currentMetting.plus(Period.ofMonths(1)); ZonedDateTime nextUsMeeting = nextMetting.withZoneSameInstant(ZoneId.of("America/New_York")); System.out.println(currentMetting); System.out.println(nextMetting); System.out.println(nextUsMeeting); //输出 2020-06-18T10:00+08:00[Asia/Shanghai] 2020-07-18T10:00+08:00[Asia/Shanghai] 2020-07-17T22:00-04:00[America/New_York]

DateTimeFormatter

System.out.println("ISO_DATE_TIME="+DateTimeFormatter.ISO_DATE_TIME.format(currentMetting)); System.out.println("RFC_1123_DATE_TIME="+DateTimeFormatter.RFC_1123_DATE_TIME.format(currentMetting)); //输出 ISO_DATE_TIME=2020-06-18T10:00:00+08:00[Asia/Shanghai] RFC_1123_DATE_TIME=Thu, 18 Jun 2020 10:00:00 +0800

老版本时间和新版本时间转换

Instant instant = Instant.now(); Date date = Date.from(instant); instant = date.toInstant(); Timestamp timestamp = Timestamp.from(instant); instant = timestamp.toInstant();