两个日期和时间之间的差异

Question

I need to find difference between to times. This is my code

LocalDateTime ltdNow = LocalDateTime.now();

LocalDateTime ltdThen = LocalDateTime.parse("2020-07-30T08:00:00");

Duration duration = Duration.between(ltdNow, ltdThen);
System.out.println(duration.toDays + " Days and " + duration.toHours);

However i need it in this format 23 Days and 17 Hours but it gives me large number like 19804 as the hour. How can i convert it to this format?

Answer 1

toHours() does exactly what it says: The number of hours between the two dates.

Try toHoursPart() , I think that's what you're looking for:

System.out.println(duration.toDays() + " Days and " + duration.toHoursPart());

Answer 2

LocalDateTime#until

import java.time.Duration;
import java.time.LocalDateTime;
import java.time.temporal.ChronoUnit;

public class Main {
    public static void main(String[] args) {
        LocalDateTime ltdThen = LocalDateTime.parse("2020-07-30T08:00:00");
        LocalDateTime ltdNow = LocalDateTime.now();

        // ###########With Java-8###########
        long days = ltdNow.until(ltdThen, ChronoUnit.DAYS);
        long hours = ltdNow.until(ltdThen, ChronoUnit.HOURS);
        System.out.println(days + " days and " + (hours % 24) + " hours.");

        // ###########Java-9 onwards###########
        Duration duration = Duration.between(ltdNow, ltdThen);
        System.out.println(duration.toDaysPart() + " days and " + duration.toHoursPart() + " hours.");
    }
}

Output:

22 days and 15 hours.
22 days and 15 hours.

Note: Duration#toDaysPart and Duration#toHoursPart was introduced with Java-9.

Answer 3

    ZoneId zone = ZoneId.of("Europe/Stockholm");
    
    ZonedDateTime zdtNow = ZonedDateTime.now(zone);
    ZonedDateTime zdtThen = LocalDateTime.parse("2020-10-26T08:00:00").atZone(zone);
    
    long days = ChronoUnit.DAYS.between(zdtNow, zdtThen);
    ZonedDateTime afterDays = zdtNow.plusDays(days);
    long hours = ChronoUnit.HOURS.between(afterDays, zdtThen);
    
    System.out.println("" + days + " days and " + hours + " hours");

Output when running today just before 18:00 Swedish time:

110 days and 14 hours

Messages:

• Don't trust the Duration class to calculate days. It calculates a day as always 24 hours. Because of summer time (DST) and other anomalies a day is occasionally longer or shorter in real life. The calculation I am doing above crosses the transition from summer time to standard time in Sweden and correctly calculates 25th October as 25 hours, not 24.
• Don't do your own division or multiplication to convert between days and hours. One, it doesn't give you a reliable result for the reason just stated. Two, if this was what you wanted, you should still leave the conversion to library classes, for example Duration .

Answer 4

Use Period:

LocalDateTime ltdNow = LocalDateTime.now();
LocalDateTime ltdThen = LocalDateTime.parse("2020-07-30T08:00:00");
Period p = Period.between(ltdThen , ltdNow );
long p2 = ChronoUnit.DAYS.between(ltdThen , ltdNow );
System.out.println("You are " + p.getYears() + " years, " + p.getMonths() +
                   " months, and " + p.getDays() +
                   " days old. (" + p2 + " days total)");