Java8日期處理類

public void dealDate() { Date date = new Date(); //Fri Feb 12 09:08:23 GMT+08:00 2021 System.out.println(date); //當前時間戳（不包含當前時區信息） Instant instant = Instant.now(); //2021-02-12T03:58:06.792Z System.out.println(instant); //當前時間戳 LocalDateTime localDateTime = LocalDateTime.now(); //2021-02-12T11:58:06.846 System.out.println(localDateTime); //當前日期 LocalDate today = LocalDate.now(); //2021-02-12 System.out.println(today); //分別獲取年月日 int year = today.getYear(); int month = today.getMonthValue(); int dayOfMonth = today.getDayOfMonth(); //Year:2021 Month:2 day:12 System.out.printf("Year:%d Month:%d day:%d%n", year, month, dayOfMonth); //創建特定的日期 LocalDate specialDate = LocalDate.of(2020, 12, 14); //The special date = 2020-12-14 System.out.println("The special date = " + specialDate); //比較時間是否相等 LocalDate date1 = LocalDate.of(2021, 2, 12); boolean equalFlag = LocalDate.now().equals(date1); //Is time equal or not ? -- true System.out.println("Is time equal or not ? -- " + equalFlag); //處理週期性的日期 LocalDate single2018 = LocalDate.of(2018, 11, 11); MonthDay singlesDay = MonthDay.of(single2018.getMonth(), single2018.getDayOfMonth()); MonthDay currentMonthDay = MonthDay.from(LocalDate.now()); boolean equalFlag1 = singlesDay.equals(currentMonthDay); //Is it 11.11 today? -- false System.out.println("Is it 11.11 today? -- " + equalFlag1); //當前時分秒 LocalTime nowTime = LocalTime.now(); //10:19:38.760 System.out.println(nowTime); //三小時後時間 LocalTime timePlus = nowTime.plusHours(3); //The time after 3 hours = 13:22:11.569 System.out.println("The time after three hours = " + timePlus); //一週後的日期 LocalDate nextWeek = LocalDate.now().plus(1, ChronoUnit.WEEKS); //The Date after 1 week = 2021-02-19 System.out.println("The Date after 1 week = " + nextWeek); //一年前的日期 LocalDate previousYear = LocalDate.now().minus(1, ChronoUnit.YEARS); //The Date before 1 year = 2020-02-12 System.out.println("The Date before 1 year = " + previousYear); //時鐘類 Clock clock = Clock.systemUTC(); //SystemClock[Z] System.out.println(clock); Clock defaultClock = Clock.systemDefaultZone(); //SystemClock[GMT+08:00] System.out.println(defaultClock); //判斷日期早晚 boolean afterFlag = specialDate.isAfter(LocalDate.now()); //2020-12-14 is after now ? -- false System.out.println(specialDate + " is after now ? -- " + afterFlag); boolean beforeFlag = specialDate.isBefore(LocalDate.now()); //2020-12-14 is before now ? -- true System.out.println(specialDate + " is before now ? -- " + beforeFlag); //處理時區 ZoneId america = ZoneId.of("America/New_York"); LocalDateTime dateTime = LocalDateTime.now(); ZonedDateTime zonedDateTime = ZonedDateTime.of(dateTime, america); //當前時區的時間與指定時區的時差： 2021-02-12T11:13:37.487-05:00[America/New_York] System.out.println("當前時區的時間與指定時區的時差： " + zonedDateTime); //YearMonth處理特定日期 YearMonth currentYearMonth = YearMonth.now(); //2021-02 include 28 days. System.out.printf("%s include %d days.%n", currentYearMonth, currentYearMonth.lengthOfMonth()); //閏年 boolean leapYear = LocalDate.now().isLeapYear(); //This year is leap year? -- false System.out.println("This year is leap year? -- " + leapYear); //計算兩個日期間的間隔 Period betweenTime = Period.between(specialDate, LocalDate.now()); //Interval between two dates are 1 mouths 29 days. System.out.printf("Interval between two dates are %d mouths %d days.%n", betweenTime.getMonths(), betweenTime.getDays()); long betweenDays = ChronoUnit.DAYS.between(specialDate, LocalDate.now()); //Interval between two dates are 60 days. System.out.printf("Interval between two dates are %d days.%n", betweenDays); //日期和時間中包含時差 ZoneOffset offset = ZoneOffset.of("+05:00"); OffsetDateTime offsetDateTime = OffsetDateTime.of(LocalDateTime.now(), offset); //dateTime with offset is : 2021-02-12T11:46:26.081+05:00 System.out.println("dateTime with offset is : " + offsetDateTime); //解析格式化日期 String dateStr = "20090901"; LocalDate formatDate = LocalDate.parse(dateStr, DateTimeFormatter.BASIC_ISO_DATE); //20090901 parse to date 2009-09-01 System.out.printf("%s parse to date %s%n", dateStr, formatDate); }