LocalDate、 LocalTime、 LocalDateTime 類的實例是 不可變對象 ,分表表示使用 ISO-8601 日曆系統的日期、時間、日期和時間。他們提供了簡單的日期或時間,並不包含當前的時間信息。也不包含與時區相關的信息。java
注:ISO-8601 日曆系統是國際標準化組織制定的現代公民的日期和時間的表示法。說白了就是全球統一標準的表示方法。ui
import org.junit.Test; import java.time.LocalDate; import java.time.LocalDateTime; import java.time.LocalTime; import java.time.Month; public class TestLocalDateTime { @Test public void test1(){ LocalDate localDate = LocalDate.now(); System.out.println(localDate);//輸出:2020-06-25 LocalTime localTime = LocalTime.now(); System.out.println(localTime);//輸出:23:12:59.211 LocalDateTime localDateTime = LocalDateTime.now(); System.out.println(localDateTime);//輸出:2020-06-25T23:12:59.211 System.out.println("-------------------------------------------"); localDate = LocalDate.of(2022,1,1); System.out.println(localDate);//輸出:2022-01-01 localDate = LocalDate.of(2023, Month.AUGUST,2); System.out.println("-------------------------------------------"); System.out.println(localDate);//輸出:2023-08-02 localTime = LocalTime.of(1,2); System.out.println(localTime);//輸出:01:02 localTime = LocalTime.of(1,2,3); System.out.println(localTime);//輸出:01:02:03 localTime = LocalTime.of(1,2,3,4); System.out.println(localTime);//輸出:01:02:03.000000004 System.out.println("-------------------------------------------"); localDateTime = LocalDateTime.of(localDate,localTime); System.out.println(localDateTime);//輸出:2023-08-02T01:02:03.000000004 localDateTime = LocalDateTime.of(2024,1,1,1,1); System.out.println(localDateTime);//輸出:2024-01-01T01:01 localDateTime = LocalDateTime.of(2024,1,1,1,1,1); System.out.println(localDateTime);//輸出:2024-01-01T01:01:01 localDateTime = LocalDateTime.of(2024,1,1,1,1,1,1); System.out.println(localDateTime);//輸出:2024-01-01T01:01:01.000000001 localDateTime = LocalDateTime.of(2024,Month.of(2),1,1,1,1,1); System.out.println(localDateTime);//輸出:2024-02-01T01:01:01.000000001 } }
@Test public void test2(){ LocalDate localDate = LocalDate.now(); System.out.println(localDate);//輸出:2020-06-30 localDate = localDate.plusYears(1); System.out.println(localDate);//輸出:2021-06-30 localDate = localDate.plusMonths(2); System.out.println(localDate);//輸出:2021-08-30 localDate = localDate.plusDays(3); System.out.println(localDate);//輸出:2021-09-02 localDate = localDate.plusWeeks(4); System.out.println(localDate);//輸出:2021-09-30 localDate = localDate.plus(Period.ofDays(10));//加10天 System.out.println(localDate);//輸出:2021-10-10 localDate = localDate.plus(Period.of(1,2,3));//加一年兩個月三天 System.out.println(localDate);//輸出:2022-12-13 localDate = localDate.plus(Period.ofYears(2));//加兩年 System.out.println(localDate);//輸出:2024-12-13 localDate = localDate.plus(1, ChronoUnit.DAYS);//加一天 System.out.println(localDate);//輸出:2024-12-14 localDate = localDate.plus(1, ChronoUnit.MONTHS);//加一個月 System.out.println(localDate);//輸出:2025-01-14 System.out.println("-------------------------------------------"); localDate = localDate.minusYears(1); System.out.println(localDate);//輸出:2024-01-14 localDate.minusMonths(1); localDate.minusDays(1); localDate.minusWeeks(1); localDate.minus(Period.ofYears(2)); //..........其餘用法和plus同樣........... System.out.println("-------------------------------------------"); LocalTime localTime = LocalTime.now(); System.out.println(localTime);//輸出:21:35:54.776 localTime = localTime.plusHours(1); System.out.println(localTime);//輸出:22:35:54.776 //..........其餘用法和localDate的同樣........... //..........LocalDateTime的用法也同樣........... }
@Test public void test3(){ LocalDate localDate = LocalDate.now(); System.out.println(localDate);//輸出:2020-06-30 System.out.println(localDate.getYear());//輸出:2020 System.out.println(localDate.getDayOfMonth());//輸出:30 //..........等....... //將天數、月份、等修改成指定的值 localDate = localDate.withDayOfMonth(22); System.out.println(localDate);//輸出:2020-06-22 localDate = localDate.withMonth(11); System.out.println(localDate);//輸出:2020-11-22 localDate = localDate.with(LocalDate.now()); System.out.println(localDate);//輸出:2020-06-30 //..........等....... System.out.println("-------------------------------------------"); Period period = localDate.until(LocalDate.of(2020, 1, 1)); System.out.println(period.get(ChronoUnit.YEARS));//輸出:0 相差 0 年 System.out.println(period.get(ChronoUnit.MONTHS));//輸出:-5 相差 1 - 6 = -5 月 System.out.println(period.get(ChronoUnit.DAYS));//輸出:-29 相差 1 - 30 = -29 天 System.out.println("-------------------------------------------"); System.out.println(localDate.isAfter(LocalDate.of(2020, 1, 1))); //輸出:true System.out.println(localDate.isBefore(LocalDate.of(2020, 1, 1))); //輸出:false System.out.println(localDate.isLeapYear());//是否閏年,輸出:true }
時間戳,以 Unix 元年:1970年1月1日00:00:00 到某個時間之間的毫秒值 。spa
@Test public void test4() { Instant ins1 = Instant.now(); // 默認獲取UTC時區(世界協調時間,基本上是美國鬼子使用,和中國時間相差大概8小時) System.out.println(ins1);//輸出結果:2020-06-30T14:28:05.217Z // 偏移量運算 OffsetDateTime offsetDateTime = ins1.atOffset(ZoneOffset.ofHours(8)); System.out.println(offsetDateTime);// 輸出結果:2020-06-30T22:28:05.217+08:00 當前系統時間,國際標準的顯示時間方式 // 獲取時間戳 System.out.println(ins1.toEpochMilli());//輸出結果:1593527285217 // 以Unix元年爲起點,進行偏移量運算 Instant ins2 = Instant.ofEpochSecond(60); System.out.println(ins2);// 運行結果:1970-01-01T00:01:00Z }
Duration : 計算兩個 「時間」 之間的間隔。code
Period:計算兩個「日期」 之間的間隔。orm
@Test public void test5() throws Exception { Instant ins1 = Instant.now(); Thread.sleep(1000); Instant ins2 = Instant.now(); Duration duration = Duration.between(ins1, ins2); System.out.println(duration.toMillis()); // 運行結果:1000 LocalTime localTime_1 = LocalTime.of(20,1,2); LocalTime localTime_2 = LocalTime.of(20,2,2); System.out.println(Duration.between(localTime_1, localTime_2).toMillis());// 運行結果:60000 System.out.println("-------------------------------------------"); LocalDate localDate_1 = LocalDate.of(2020,1, 1); LocalDate localDate_2 = LocalDate.now(); Period period = Period.between(localDate_1, localDate_2); System.out.println(period.getYears()); // 運行結果:0 System.out.println(period.getMonths()); // 運行結果:5 System.out.println(period.getDays()); // 運行結果:29 }
TemporalAdjuster : 時間校訂器。有時咱們可能須要獲取例如:將日期調整到「下個週日」等操做。
TemporalAdjusters : 該類經過靜態方法提供了大量的經常使用 TemporalAdjuster 的實現。對象
@Test public void test6(){ //TemporalAdjuster : 時間校訂器。有時咱們可能須要獲取例如:將日期調整到「下個週日」等操做。 //TemporalAdjusters : 該類經過靜態方法提供了大量的經常使用 TemporalAdjuster 的實現。 LocalDate localDate = LocalDate.now(); System.out.println(localDate);// 輸出:2020-07-01 localDate = localDate.with(TemporalAdjusters.lastDayOfMonth()); System.out.println(localDate);// 輸出:2020-07-31 localDate = localDate.with(TemporalAdjusters.next(DayOfWeek.SUNDAY)); System.out.println(localDate);// 輸出:2020-08-02 localDate = LocalDate.of(2020,7,3);//週五 //自定義校訂器:獲取下一個工做日 localDate = localDate.with(ld -> { LocalDate ld_ = (LocalDate) ld; DayOfWeek dayOfWeek = ld_.getDayOfWeek(); if (dayOfWeek.equals(DayOfWeek.FRIDAY)) { return ld_.plusDays(3); } else if (dayOfWeek.equals(DayOfWeek.SATURDAY)) { return ld_.plusDays(2); } else { return ld_.plusDays(1); } }); System.out.println(localDate);// 輸出:2020-07-06 }
java.time.format.DateTimeFormatter 類:該類提供了三種格式化方法:blog
@Test public void test7(){ // DateTimeFormatter 格式化 時間/日期 LocalDateTime localDateTime = LocalDateTime.now(); System.out.println(localDateTime);// 輸出: 2020-07-01T21:56:11.978 DateTimeFormatter formatter = DateTimeFormatter.ISO_DATE; System.out.println(formatter.format(localDateTime));// 輸出: 2020-07-01 formatter = DateTimeFormatter.ofPattern("yyyy年MM月dd日 HH時mm分ss秒"); System.out.println(formatter.format(localDateTime));// 輸出: 2020年07月01日 21時56分11秒 System.out.println(formatter.parse("2020年07月01日 21時55分08秒"));// 輸出: {},ISO resolved to 2020-07-01T21:55:08 System.out.println(localDateTime.parse("2020年07月01日 21時55分08秒",formatter));// 輸出: 2020-07-01T21:55:08 }
Java8 中加入了對時區的支持,帶時區的時間爲分別爲:ZonedDate、 ZonedTime、 ZonedDateTime。
其中每一個時區都對應着 ID,地區ID都爲 「{區域}/{城市}」的格式,例如 : Asia/Shanghai 等。get
@Test public void test8(){ //時區:ZonedDate、 ZonedTime、 ZonedDateTime Set<String> zoneIds = ZoneId.getAvailableZoneIds();//獲取全部時區 System.out.println(zoneIds);//輸出: [Asia/Aden, America/Cuiaba, Etc/GMT+9, Etc/GMT+8, Africa/Nairobi, America/Marigot, Asia/Aqtau, .....等等..... LocalDateTime localDateTime = LocalDateTime.now(); System.out.println(localDateTime);// 輸出: 2020-07-01T22:06:59.130 localDateTime = LocalDateTime.now(ZoneId.of("America/Marigot")); System.out.println(localDateTime);// 輸出: 2020-07-01T10:06:59.131 localDateTime = LocalDateTime.now(ZoneId.of("Etc/GMT+8")); System.out.println(localDateTime);// 輸出: 2020-07-01T06:06:59.131 System.out.println("-------------------------------------------"); localDateTime = LocalDateTime.now(); System.out.println(localDateTime);// 輸出: 2020-07-01T22:10:39.940 ZonedDateTime zonedDateTime = localDateTime.atZone(ZoneId.of("Europe/Vatican"));//帶時區的日期時間 System.out.println(zonedDateTime);// 輸出: 2020-07-01T22:10:39.940+02:00[Europe/Vatican] }