java-time – Page 7 – Tarik Billa

Java 8 date-time: get start of day from ZonedDateTime

February 3, 2023 by Tarik

Updated for sake of correction: In most cases yes the same, see following example for Brazil when switching from winter to summer time: ZonedDateTime zdt = ZonedDateTime.of(2015, 10, 18, 0, 30, 0, 0, ZoneId.of(“America/Sao_Paulo”)); // switch to summer time ZonedDateTime zdt1 = zdt.truncatedTo(ChronoUnit.DAYS); ZonedDateTime zdt2 = zdt.toLocalDate().atStartOfDay(zdt.getZone()); System.out.println(zdt); // 2015-10-18T01:30-02:00[America/Sao_Paulo] System.out.println(zdt1); // 2015-10-18T01:00-02:00[America/Sao_Paulo] System.out.println(zdt2); // … Read more

Unit testing a class with a Java 8 Clock

February 3, 2023 by Tarik

I don’t want to add a Clock argument to the method because the real code shouldn’t be concerned with passing in a clock. No… but you might want to consider it as a constructor parameter. Basically you’re saying that your class needs a clock with which to work… so that’s a dependency. Treat it as … Read more

Why can’t I get a duration in minutes or hours in java.time?

January 31, 2023 by Tarik

“Why was it implemented that way?” Other answers deal with the toXxx() methods that allow the hours/minutes to be queried. I’ll try to deal with the why. The TemporalAmount interface and get(TemporalUnit) method was added fairly late in the process. I personally was not entirely convinced that we had enough evidence of the right way … Read more

What does ‘PT’ prefix stand for in Duration?

January 28, 2023 by Tarik

As can be found on the page Jesper linked to (ISO-8601 – Data elements and interchange formats – Information interchange – Representation of dates and times) P is the duration designator (for period) placed at the start of the duration representation. Y is the year designator that follows the value for the number of years. … Read more

What is the difference between year and year-of-era?

January 24, 2023 by Tarik

The answer lies in the documentation for IsoChronology era – There are two eras, ‘Current Era’ (CE) and ‘Before Current Era’ (BCE). year-of-era – The year-of-era is the same as the proleptic-year for the current CE era. For the BCE era before the ISO epoch the year increases from 1 upwards as time goes backwards. … Read more

long timestamp to LocalDateTime

January 24, 2023 by Tarik

You need to pass timestamp in milliseconds: long test_timestamp = 1499070300000L; LocalDateTime triggerTime = LocalDateTime.ofInstant(Instant.ofEpochMilli(test_timestamp), TimeZone.getDefault().toZoneId()); System.out.println(triggerTime); Result: 2017-07-03T10:25 Or use ofEpochSecond instead: long test_timestamp = 1499070300L; LocalDateTime triggerTime = LocalDateTime.ofInstant(Instant.ofEpochSecond(test_timestamp), TimeZone.getDefault().toZoneId()); System.out.println(triggerTime); Result: 2017-07-03T10:25

How can I mock java.time.LocalDate.now()

January 21, 2023 by Tarik

In your code, replace LocalDate.now() with LocalDate.now(clock);. You can then pass Clock.systemDefaultZone() for production and a fixed clock for testing. This is an example : First, inject the Clock. If you are using spring boot just do a : @Bean public Clock clock() { return Clock.systemDefaultZone(); } Second, call LocalDate.now(clock) in your code : @Component … Read more

How to convert from Instant to LocalDate

January 21, 2023 by Tarik

Java 9+ LocalDate.ofInstant(…) arrived in Java 9. Instant instant = Instant.parse(“2020-01-23T00:00:00Z”); ZoneId zone = ZoneId.of(“America/Edmonton”); LocalDate date = LocalDate.ofInstant(instant, zone); See code run live at IdeOne.com. Notice the date is 22nd rather than 23rd as that time zone uses an offset several hours before UTC. 2020-01-22 Java 8 If you are using Java 8, then … Read more

Difference between year-of-era and week-based-year?

January 20, 2023 by Tarik

That’s year value for “year-week” style dates, as in 2006-W52. It may be off the year-of-era value by +1 or -1 if the week in question straddles year boundary. See http://en.wikipedia.org/wiki/ISO_8601#Week_dates

How to obtain the end of the day when given a LocalDate?

January 16, 2023 by Tarik

Here are a few alternatives, depending on what you need: LocalDate.now().atTime(23, 59, 59); //23:59:59 LocalDate.now().atTime(LocalTime.MAX); //23:59:59.999999999 But there is no built-in method. As commented by @JBNizet, if you want to create an interval, you can also use an interval up to midnight, exclusive.