时间类

LocalDate

// the current date
LocalDate currentDate = LocalDate.now();
// 2014-02-10
LocalDate tenthFeb2014 = LocalDate.of(2014, Month.FEBRUARY, 10);
// months values start at 1 (2014-08-01)
LocalDate firstAug2014 = LocalDate.of(2014, 8, 1);
// the 65th day of 2010 (2010-03-06)
LocalDate sixtyFifthDayOf2010 = LocalDate.ofYearDay(2010, 65);

LocalDate & LocalDateTime

LocalTime currentTime = LocalTime.now(); // current time
LocalTime midday = LocalTime.of(12, 0); // 12:00
LocalTime afterMidday = LocalTime.of(13, 30, 15); // 13:30:15
// 12345th second of day (03:25:45)
LocalTime fromSecondsOfDay = LocalTime.ofSecondOfDay(12345);
// dates with times, e.g. 2014-02-18 19:08:37.950
LocalDateTime currentDateTime = LocalDateTime.now();
// 2014-10-02 12:30
LocalDateTime secondAug2014 = LocalDateTime.of(2014, 10, 2, 12, 30);
// 2014-12-24 12:00
LocalDateTime christmas2014 = LocalDateTime.of(2014, Month.DECEMBER, 24, 12, 0);
//特定时区
// current (local) time in Los Angeles
LocalTime currentTimeInLosAngeles = LocalTime.now(ZoneId.of("America/Los_Angeles"));
// current time in UTC time zone
LocalTime nowInUtc = LocalTime.now(Clock.systemUTC());

• 常用方法

  LocalDate date = LocalDate.of(2014, 2, 15); // 2014-06-15
  boolean isBefore = LocalDate.now().isBefore(date); // false
  // information about the month
  Month february = date.getMonth(); // FEBRUARY
  int februaryIntValue = february.getValue(); // 2
  int minLength = february.minLength(); // 28
  int maxLength = february.maxLength(); // 29
  Month firstMonthOfQuarter = february.firstMonthOfQuarter(); // JANUARY
  // information about the year
  int year = date.getYear(); // 2014
  int dayOfYear = date.getDayOfYear(); // 46
  int lengthOfYear = date.lengthOfYear(); // 365
  boolean isLeapYear = date.isLeapYear(); // false
  DayOfWeek dayOfWeek = date.getDayOfWeek();
  int dayOfWeekIntValue = dayOfWeek.getValue(); // 6
  String dayOfWeekName = dayOfWeek.name(); // SATURDAY
  int dayOfMonth = date.getDayOfMonth(); // 15
  LocalDateTime startOfDay = date.atStartOfDay(); // 2014-02-15 00:00
  // time information
  LocalTime time = LocalTime.of(15, 30); // 15:30:00
  int hour = time.getHour(); // 15
  int second = time.getSecond(); // 0
  int minute = time.getMinute(); // 30
  int secondOfDay = time.toSecondOfDay(); // 55800
  

• 数学操作

  LocalDate tomorrow = LocalDate.now().plusDays(1);
  // before 5 houres and 30 minutes
  LocalDateTime dateTime = LocalDateTime.now().minusHours(5).minusMinutes(30);
  

• 日期操作工具

  LocalDate date = LocalDate.of(2014, Month.FEBRUARY, 25); // 2014-02-25
  // first day of february 2014 (2014-02-01)
  LocalDate firstDayOfMonth = date.with(TemporalAdjusters.firstDayOfMonth());
  // last day of february 2014 (2014-02-28)
  LocalDate lastDayOfMonth = date.with(TemporalAdjusters.lastDayOfMonth());
  //对于这种静态方法，可以静态引入简化使用import static java.time.temporal.TemporalAdjusters.*;
  

Year

Year currentYear = Year.now();
Year twoThousand = Year.of(2000);
boolean isLeap = currentYear.isLeap(); // false
int length = currentYear.length(); // 365
// sixtyFourth day of 2014 (2014-03-05)
LocalDate date = Year.of(2014).atDay(64);

Time Zones

ZoneId losAngeles = ZoneId.of("America/Los_Angeles");
ZoneId berlin = ZoneId.of("Europe/Berlin");
// 2014-02-20 12:00
LocalDateTime dateTime = LocalDateTime.of(2014, 02, 20, 12, 0);
// 2014-02-20 12:00, Europe/Berlin (+01:00)
ZonedDateTime berlinDateTime = ZonedDateTime.of(dateTime, berlin);
// 2014-02-20 03:00, America/Los_Angeles (-08:00)
ZonedDateTime losAngelesDateTime = berlinDateTime.withZoneSameInstant(losAngeles);
int offsetInSeconds = losAngelesDateTime.getOffset().getTotalSeconds(); // -28800
// a collection of all available zones
Set<String> allZoneIds = ZoneId.getAvailableZoneIds();
// using offsets
LocalDateTime date = LocalDateTime.of(2013, Month.JULY, 20, 3, 30);
ZoneOffset offset = ZoneOffset.of("+05:00");
// 2013-07-20 03:30 +05:00
OffsetDateTime plusFive = OffsetDateTime.of(date, offset);
// 2013-07-19 20:30 -02:00
OffsetDateTime minusTwo = plusFive.withOffsetSameInstant(ZoneOffset.ofHours(-2));

Timestamps

// current time
Instant now = Instant.now();
// from unix timestamp, 2010-01-01 12:00:00
Instant fromUnixTimestamp = Instant.ofEpochSecond(1262347200);
// same time in millis
Instant fromEpochMilli = Instant.ofEpochMilli(1262347200000l);
// parsing from ISO 8601
Instant fromIso8601 = Instant.parse("2010-01-01T12:00:00Z");
// toString() returns ISO 8601 format, e.g. 2014-02-15T01:02:03Z
String toIso8601 = now.toString();
// as unix timestamp
long toUnixTimestamp = now.getEpochSecond();
// in millis
long toEpochMillis = now.toEpochMilli();
// plus/minus methods are available too
Instant nowPlusTenSeconds = now.plusSeconds(10);

Instant

• 用于处理与日期和时间相关的操作，特别是在需要处理时区信息的情况下非常有用。

  Instant now = Instant.now();
  Instant timestamp = Instant.ofEpochSecond(1634032035); // 从Unix时间戳创建Instant实例
  Instant start = Instant.ofEpochSecond(1634032035);
  Instant end = Instant.now();
  
  Duration duration = Duration.between(start, end);
  System.out.println("时间差：" + duration);
  
  // Instant 转换为 LocalDateTime
  Instant instant = Instant.now();
  LocalDateTime localDateTime = LocalDateTime.ofInstant(instant, ZoneId.systemDefault());
  
  // LocalDateTime 转换为 Instant
  LocalDateTime localDateTime = LocalDateTime.now();
  Instant instant = localDateTime.toInstant(ZoneOffset.UTC);
  

时间区间

// periods
LocalDate firstDate = LocalDate.of(2010, 5, 17); // 2010-05-17
LocalDate secondDate = LocalDate.of(2015, 3, 7); // 2015-03-07
Period period = Period.between(firstDate, secondDate);
int days = period.getDays(); // 18
int months = period.getMonths(); // 9
int years = period.getYears(); // 4
boolean isNegative = period.isNegative(); // false
Period twoMonthsAndFiveDays = Period.ofMonths(2).plusDays(5);
LocalDate sixthOfJanuary = LocalDate.of(2014, 1, 6);
// add two months and five days to 2014-01-06, result is 2014-03-11
LocalDate eleventhOfMarch = sixthOfJanuary.plus(twoMonthsAndFiveDays);
// durations
Instant firstInstant= Instant.ofEpochSecond( 1294881180 ); // 2011-01-13 01:13
Instant secondInstant = Instant.ofEpochSecond(1294708260); // 2011-01-11 01:11
Duration between = Duration.between(firstInstant, secondInstant);
// negative because firstInstant is after secondInstant (-172920)
long seconds = between.getSeconds();
// get absolute result in minutes (2882)
long absoluteResult = between.abs().toMinutes();
// two hours in seconds (7200)
long twoHoursInSeconds = Duration.ofHours(2).getSeconds();

格式化

// 2014-04-01 10:45
LocalDateTime dateTime = LocalDateTime.of(2014, Month.APRIL, 1, 10, 45);
// format as basic ISO date format (20140220)
String asBasicIsoDate = dateTime.format(DateTimeFormatter.BASIC_ISO_DATE);
// format as ISO week date (2014-W08-4)
String asIsoWeekDate = dateTime.format(DateTimeFormatter.ISO_WEEK_DATE);
// format ISO date time (2014-02-20T20:04:05.867)
String asIsoDateTime = dateTime.format(DateTimeFormatter.ISO_DATE_TIME);
// using a custom pattern (01/04/2014)
String asCustomPattern = dateTime.format(DateTimeFormatter.ofPattern("dd/MM/yyyy"));
// french date formatting (1. avril 2014)
String frenchDate = dateTime.format(DateTimeFormatter.ofPattern("d. MMMM yyyy", new Locale("fr")));
// using short german date/time formatting (01.04.14 10:45)
DateTimeFormatter formatter = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.SHORT)
.withLocale(new Locale("de"));
String germanDateTime = dateTime.format(formatter);
// parsing date strings
LocalDate fromIsoDate = LocalDate.parse("2014-01-20");
LocalDate fromIsoWeekDate = LocalDate.parse("2014-W14-2", DateTimeFormatter.ISO_WEEK_DATE);
LocalDate fromCustomPattern = LocalDate.parse("20.01.2014", DateTimeFormatter.ofPattern("dd.MM.yyyy"));

时间对象之间的转换

// LocalDate/LocalTime <-> LocalDateTime
LocalDate date = LocalDate.now();
LocalTime time = LocalTime.now();
LocalDateTime dateTimeFromDateAndTime = LocalDateTime.of(date, time);
LocalDate dateFromDateTime = LocalDateTime.now().toLocalDate();
LocalTime timeFromDateTime = LocalDateTime.now().toLocalTime();
// Instant <-> LocalDateTime
Instant instant = Instant.now();
LocalDateTime dateTimeFromInstant = LocalDateTime.ofInstant(instant, ZoneId.of("America/Los_Angeles"));
Instant instantFromDateTime = LocalDateTime.now().toInstant(ZoneOffset.ofHours(-2));
// convert old date/calendar/timezone classes
Instant instantFromDate = new Date().toInstant();
Instant instantFromCalendar = Calendar.getInstance().toInstant();
ZoneId zoneId = TimeZone.getDefault().toZoneId();
ZonedDateTime zonedDateTimeFromGregorianCalendar = new GregorianCalendar().toZonedDateTime();
// convert to old classes
Date dateFromInstant = Date.from(Instant.now());
TimeZone timeZone = TimeZone.getTimeZone(ZoneId.of("America/Los_Angeles"));
GregorianCalendar gregorianCalendar = GregorianCalendar.from(ZonedDateTime.now());