java新時間類

時間

java8以前使用的時間很多方法都已經廢棄了，而且不是執行緒安全的，java8提供了一系列的時間類，這些時間類都是執行緒安全的

LocalDate、LocalTime、LocalDateTime

這三個關於時間的類在使用上都類似

/**  	 * LocalDate  	 */  @Test  public void test1() {    LocalDate date1 = LocalDate.now();    System.out.println(date1);//2020-03-30      LocalDate plusYears = date1.plusYears(1);    System.out.println(plusYears);//2021-03-30      LocalDate minusDays = date1.minusDays(2);    System.out.println(minusDays);//2020-03-28      LocalDate date2 = LocalDate.of(2019, 3, 30);    System.out.println(date2.getYear());//2019  }    /**  	 * LocalTime  	 */  @Test  public void test2() {    LocalTime now = LocalTime.now();    System.out.println(now);//21:15:23.418      int minute = now.getMinute();    System.out.println(minute);//15      int second = now.getSecond();    System.out.println(second);//23      LocalTime of = LocalTime.of(10, 10, 10);    System.out.println(of);//10:10:10      LocalTime minusMinutes = of.minusMinutes(2);    System.out.println(minusMinutes);//10:08:10      LocalTime plusHours = of.plusHours(2);    System.out.println(plusHours);//12:10:10  }    /**  	 * LocalDateTime  	 */  @Test  public void test3() {    LocalDateTime now = LocalDateTime.now();    System.out.println(now);//2020-03-30T21:20:37.961      int minute = now.getMinute();    System.out.println(minute);//20      LocalDateTime plusMinutes = now.plusMinutes(20);    System.out.println(plusMinutes);//2020-03-30T21:40:37.961      LocalDateTime minusYears = now.minusYears(2);    System.out.println(minusYears);//2018-03-30T21:20:37.961      LocalDateTime of = LocalDateTime.of(2021, 3, 30, 21, 19, 50);    System.out.println(of);//2021-03-30T21:19:50  }

時間戳

/**  	 * Instant  	 */  @Test  public void test4() {    Instant now = Instant.now();    System.out.println(now);//2020-03-30T13:26:10.640Z      Instant plusSeconds = now.plusSeconds(10);    System.out.println(plusSeconds);//2020-03-30T13:26:20.640Z      //獲取時間戳相對於1970年0時0分0秒的毫秒數    long epochMilli = plusSeconds.toEpochMilli();    System.out.println(epochMilli);//1585574780640  }

Duration獲取時間間隔

/**  	 * Duration  	 */  @Test  public void test5() {    Instant start = Instant.now();    Instant end = start.plusSeconds(10);    Duration duration = Duration.between(start, end);    long seconds = duration.getSeconds();    //獲取時間間隔的秒數    System.out.println(seconds);//10      //獲取時間間隔的毫秒數    long millis = duration.toMillis();    System.out.println(millis);//10000  }

Peroid獲取日期間隔

@Test  public void test6() {    LocalDate date1 = LocalDate.now();    LocalDate date2 = date1.plusYears(2);    Period period = Period.between(date1, date2);    //獲取兩時間間隔的月數,指兩個月份的間隔數，並不是時間間隔的總月數    int months = period.getMonths();    System.out.println(months);//0  }

TemporalAdjuster矯正日期

@Test  public void test7() {    LocalDate date1 = LocalDate.now();    System.out.println(date1);//2020-03-31      //TemporalAdjusters類中封裝了一些常用地時間矯正方法    TemporalAdjuster next = TemporalAdjusters.next(DayOfWeek.FRIDAY);    LocalDate date2 = date1.with(next);    System.out.println(date2);//2020-04-03      //自定義時間矯正器    LocalDate date3 = date1.with(x->{      LocalDate ld=(LocalDate)x;      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(date3);//2020-04-01  }

由於TemporalAdjuster是一個函數式介面，所以我們可以使用lambda表達式自定義矯正規則

@FunctionalInterface  public interface TemporalAdjuster {    Temporal adjustInto(Temporal temporal);  }

DateTimeFormatter格式化日期時間

@Test  public void test8() {    LocalDateTime dateTime1 = LocalDateTime.now();    System.out.println(dateTime1);//2020-03-31T18:28:04.256      DateTimeFormatter formatter1 = DateTimeFormatter.ISO_DATE;    String format1 = dateTime1.format(formatter1);    System.out.println(format1);//2020-03-31      DateTimeFormatter formatter2 = DateTimeFormatter.ofPattern("yyyy年MM月dd日HH時mm分ss秒");    String format2 = dateTime1.format(formatter2);    System.out.println(format2);//2020年03月31日18時28分04秒      LocalDateTime dateTime2 = LocalDateTime.parse(format2, formatter2);    System.out.println(dateTime2);//2020-03-31T18:28:04  }

ZoneDate

@Test  public void test9() {    //獲取可用時區    ZoneId.getAvailableZoneIds().forEach(System.out::println);      LocalDate date1 = LocalDate.now(ZoneId.of("Asia/Tokyo"));    System.out.println(date1);//2020-03-31  }

ZoneTime

@Test  public void test10() {    LocalTime time1 = LocalTime.now(ZoneId.of("Asia/Tokyo"));    System.out.println(time1);//19:44:15.228      OffsetTime atOffset = time1.atOffset(ZoneOffset.ofHours(2));    System.out.println(atOffset);//19:44:15.228+02:00  }

ZoneDateTime

@Test  public void test11() {    LocalDateTime dateTime1 = LocalDateTime.now(ZoneId.of("Asia/Shanghai"));    System.out.println(dateTime1);//2020-03-31T18:51:07.136      ZonedDateTime atZone = dateTime1.atZone(ZoneId.of("Asia/Shanghai"));    System.out.println(atZone);//2020-03-31T18:51:07.136+08:00[Asia/Shanghai]	+09:00表示時間比格林尼治時間快9小時  }

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