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@mscharhag
Created February 24, 2014 19:53
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Examples for using the Java 8 Date and Time API (JSR 310)
import java.time.*;
import java.time.format.DateTimeFormatter;
import java.time.format.FormatStyle;
import java.time.temporal.ChronoUnit;
import java.time.temporal.TemporalAdjusters;
import java.util.*;
import static java.time.temporal.TemporalAdjusters.*;
public class Java8DateTimeExamples {
// This class shows the usage of the Java 8 date/time API
// For more information have a look at this blog post:
// http://www.mscharhag.com/2014/02/java-8-datetime-api.html
private static void dateTimes() {
// dates, e.g. 2014-02-18
// 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);
// times, e.g. 19:12:30.733
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. 2014-02-18T19:08:37.950
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);
// By default LocalDate and LocalTime will use the system clock in the default time zone
// We can change this by providing a timezone or an alternative clock implementation
// 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());
System.out.println("date/time creation: currentDate: " + currentDate);
System.out.println("date/time creation: tenthFeb2014: " + tenthFeb2014);
System.out.println("date/time creation: firstAug2014: " + firstAug2014);
System.out.println("date/time creation: sixtyFifthDayOf2010: " + sixtyFifthDayOf2010);
System.out.println("date/time creation: currentTime: " + currentTime);
System.out.println("date/time creation: midday: " + midday);
System.out.println("date/time creation: afterMidday: " + afterMidday);
System.out.println("date/time creation: fromSecondsOfDay: " + fromSecondsOfDay);
System.out.println("date/time creation: currentTimeInLosAngeles: " + currentTimeInLosAngeles);
System.out.println("date/time creation: currentDateTime: " + currentDateTime);
System.out.println("date/time creation: secondAug2014: " + secondAug2014);
System.out.println("date/time creation: christmas2014: " + christmas2014);
}
private static void dateTimeInformation() {
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(); // 2014-02-15T00:00
// 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
System.out.println("dateTimeInformation: february: " + february);
System.out.println("dateTimeInformation: februaryIntValue: " + februaryIntValue);
System.out.println("dateTimeInformation: firstMonthOfQuarter: " + firstMonthOfQuarter);
System.out.println("dateTimeInformation: minLength: " + minLength);
System.out.println("dateTimeInformation: maxLength: " + maxLength);
System.out.println("dateTimeInformation: year: " + year);
System.out.println("dateTimeInformation: dayOfYear: " + dayOfYear);
System.out.println("dateTimeInformation: lengthOfYear: " + lengthOfYear);
System.out.println("dateTimeInformation: isLeapYear: " + isLeapYear);
System.out.println("dateTimeInformation: dayOfWeekName: " + dayOfWeekName);
System.out.println("dateTimeInformation: dayOfWeekIntValue: " + dayOfWeekIntValue);
System.out.println("dateTimeInformation: dayOfMonth: " + dayOfMonth);
System.out.println("dateTimeInformation: startOfDay: " + startOfDay);
System.out.println("dateTimeInformation: hour: " + hour);
System.out.println("dateTimeInformation: second: " + second);
System.out.println("dateTimeInformation: minute: " + minute);
System.out.println("dateTimeInformation: secondOfDay: " + secondOfDay);
System.out.println("dateTimeInformation: isBefore: " + isBefore);
}
private static void 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);
System.out.println("year: currentYear: " + currentYear);
System.out.println("year: twoThousand: " + twoThousand);
System.out.println("year: isLeap: " + isLeap);
System.out.println("year: length: " + length);
System.out.println("year: date: " + date);
}
private static void periodsAndDurations() {
// 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();
System.out.println("periodsAndDurations: days: " + days);
System.out.println("periodsAndDurations: months: " + months);
System.out.println("periodsAndDurations: years: " + years);
System.out.println("periodsAndDurations: isNegative: " + isNegative);
System.out.println("periodsAndDurations: eleventhOfMarch: " + eleventhOfMarch);
System.out.println("periodsAndDurations: seconds: " + seconds);
System.out.println("periodsAndDurations: absoluteResult: " + absoluteResult);
System.out.println("periodsAndDurations: twoHoursInSeconds: " + twoHoursInSeconds);
}
private static void additionSubtraction() {
LocalDate tomorrow = LocalDate.now().plusDays(1);
// before 5 houres and 30 minutes
LocalDateTime dateTime = LocalDateTime.now().minusHours(5).minusMinutes(30);
System.out.println("additionSubtraction: tomorrow: " + tomorrow);
System.out.println("additionSubtraction: dateTime: " + dateTime);
}
private static void parsingFormatting() {
// 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"));
System.out.println("parsingFormatting: asBasicIsoDate: " + asBasicIsoDate);
System.out.println("parsingFormatting: asIsoWeekDate: " + asIsoWeekDate);
System.out.println("parsingFormatting: asIsoDateTime: " + asIsoDateTime);
System.out.println("parsingFormatting: asCustomPattern: " + asCustomPattern);
System.out.println("parsingFormatting: fromIsoDate: " + fromIsoDate);
System.out.println("parsingFormatting: fromIsoWeekDate: " + fromIsoWeekDate);
System.out.println("parsingFormatting: fromCustomPattern: " + fromCustomPattern);
System.out.println("parsingFormatting: frenchDate: " + frenchDate);
System.out.println("parsingFormatting: germanDateTime: " + germanDateTime);
}
private static void temporalAdjuster() {
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());
// more fluent using static imports
// last day of 2014 (2014-12-31)
LocalDate lastDayOfYear = date.with(lastDayOfYear());
// first day of next month (2014-03-01)
LocalDate firstDayOfNextMonth = date.with(firstDayOfNextMonth());
// next sunday (2014-03-02)
LocalDate nextSunday = date.with(next(DayOfWeek.SUNDAY));
System.out.println("temporalAdjuster: firstDayOfMonth: " + firstDayOfMonth);
System.out.println("temporalAdjuster: lastDayOfMonth: " + lastDayOfMonth);
System.out.println("temporalAdjuster: lastDayOfYear: " + lastDayOfYear);
System.out.println("temporalAdjuster: firstDayOfNextMonth: " + firstDayOfNextMonth);
System.out.println("temporalAdjuster: nextSunday: " + nextSunday);
}
private static void timezones() {
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 22:30 +05:00
OffsetDateTime plusFive = OffsetDateTime.of(date, offset);
// 2013-07-19 20:30 -02:00
OffsetDateTime minusTwo = plusFive.withOffsetSameInstant(ZoneOffset.ofHours(-2));
System.out.println("timezones: berlinDateTime: " + berlinDateTime);
System.out.println("timezones: losAngelesDateTime: " + losAngelesDateTime);
System.out.println("timezones: offsetInSeconds: " + offsetInSeconds);
System.out.println("timezones: allZoneIds: " + allZoneIds);
System.out.println("timezones: offset: " + offset);
System.out.println("timezones: plusFive: " + plusFive);
System.out.println("timezones: minusTwo: " + minusTwo);
}
private static void conversion() {
// 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 from/to 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();
Date dateFromInstant = Date.from(Instant.now());
TimeZone timeZone = TimeZone.getTimeZone(ZoneId.of("America/Los_Angeles"));
GregorianCalendar gregorianCalendar = GregorianCalendar.from(ZonedDateTime.now());
}
private static void 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
String toIso8601 = now.toString();
// as unix timestamp
long toUnixTimestamp = now.getEpochSecond();
// in millis
long toEpochMillis = now.toEpochMilli();
// native plusSeconds() method to add 10 seconds
Instant nowPlusTenSeconds = now.plusSeconds(10);
// no native support for units like days.
Instant nowPlusTwoDays = now.plus(2, ChronoUnit.DAYS);
Instant nowMinusTwoDays = now.minus(Duration.ofDays(2));
System.out.println("timestamps now: " + now);
System.out.println("timestamps fromUnixTimestamp: " + fromUnixTimestamp);
System.out.println("timestamps fromEpochMilli: " + fromEpochMilli);
System.out.println("timestamps fromIso8601: " + fromIso8601);
System.out.println("timestamps toIso8601: " + toIso8601);
System.out.println("timestamps toUnixTimestamp: " + toUnixTimestamp);
System.out.println("timestamps toEpochMillis: " + toEpochMillis);
System.out.println("timestamps nowPlusTenSeconds: " + nowPlusTenSeconds);
System.out.println("timestamps nowPlusTwoDays: " + nowPlusTwoDays);
System.out.println("timestamps nowMinusTwoDays: " + nowMinusTwoDays);
}
public static void main(String[] args) {
dateTimes();
dateTimeInformation();
year();
temporalAdjuster();
additionSubtraction();
timezones();
timestamps();
periodsAndDurations();
parsingFormatting();
conversion();
}
}
@sbibek
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sbibek commented Mar 7, 2018

How to represent the timestamp which is in epoch nanoseconds in localdatetime?

@aleksamarkoni
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Many thanks, I don't have a cookie, but I would gladly give you one :)

@ivanvasheka
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Great example! Could you please add a comparing / equals section? For example, how to say if two Instants are in the same Day / Week / Month / Year ? And maybe there are some tools to properly format relative date text (e.g. if the Instant is today or yesterday or on the last week? Thanks!

@LiuHongze19920301
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How can I convert from unix timestamp from/to LocalDate and/or LocalTimeDate ?

I know I could use Calendar as a helper class, but is there a better way?

public static LocalDate mapDateToLocalDate(Date date) {
Instant instant = date.toInstant();
ZoneId defaultZoneId = ZoneId.systemDefault();
return instant.atZone(defaultZoneId).toLocalDate();
}

public static LocalDateTime mapDateToLocalDateTime(Date date) {
Instant instant = date.toInstant();
ZoneId defaultZoneId = ZoneId.systemDefault();
return instant.atZone(defaultZoneId).toLocalDateTime();
}

public static Date mapLocalDateToDate(LocalDate localDate) {
ZoneId defaultZoneId = ZoneId.systemDefault();
Instant instant = localDate.atStartOfDay().atZone(defaultZoneId).toInstant();
return Date.from(instant);
}

@gildas
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gildas commented Sep 13, 2019

I didn't see any test for stuff like 2011-12-03T10:15:30+01:00
In my test, Instant.parse("2011-12-03T10:15:30+01:00" fails, whereas it shouldn't since the date is a valid ISO 8601. This exact string even comes from the Java doc on Oracle...

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