Java LocalTime

Java LocalTime

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Java LocalTime class is an immutable class that represents time with a default format of hour-minute-second. It inherits Object class and implements the Comparable interface.

MethodOutput
LocalTime.of(13, 12, 11)13:12:11
LocalTime.MIDNIGHT00:00
LocalTime.NOON12:00
LocalTime.now()Current time from system clock
LocalTime.MAXThe maximum supported local time 23:59:59.999999999
LocalTime.MINThe minimum supported local time 00:00
LocalTime.ofSecondOfDay(84399)23:59:59 , Obtains Time from second-of-day value
LocalTime.ofNanoOfDay(2000000000)00:00:02 , Obtains Time from nanos-of-day value

Amount of time between two LocalTime

There are two equivalent ways to calculate the amount of time unit between two LocalTime: (1) through until(Temporal, TemporalUnit) method and through (2) TemporalUnit.between(Temporal, Temporal).

import java.time.LocalTime;
import java.time.temporal.ChronoUnit;

public class AmountOfTime {

     public static void main(String[] args) {
          LocalTime start = LocalTime.of(1, 0, 0); // hour, minute, second
          LocalTime end = LocalTime.of(2, 10, 20); // hour, minute, second

           long halfDays1 = start.until(end, ChronoUnit.HALF_DAYS); // 0
           long halfDays2 = ChronoUnit.HALF_DAYS.between(start, end); // 0

           long hours1 = start.until(end, ChronoUnit.HOURS); // 1
           long hours2 = ChronoUnit.HOURS.between(start, end); // 1
           long minutes1 = start.until(end, ChronoUnit.MINUTES); // 70
           long minutes2 = ChronoUnit.MINUTES.between(start, end); // 70

            long seconds1 = start.until(end, ChronoUnit.SECONDS); // 4220
            long seconds2 = ChronoUnit.SECONDS.between(start, end); // 4220
    
            long millisecs1 = start.until(end, ChronoUnit.MILLIS); // 4220000
            long millisecs2 = ChronoUnit.MILLIS.between(start, end); // 4220000
 
            long microsecs1 = start.until(end, ChronoUnit.MICROS); // 4220000000
            long microsecs2 = ChronoUnit.MICROS.between(start, end); // 4220000000

            long nanosecs1 = start.until(end, ChronoUnit.NANOS); // 4220000000000
            long nanosecs2 = ChronoUnit.NANOS.between(start, end); // 4220000000000

           // Using others ChronoUnit will be thrown UnsupportedTemporalTypeException.
          // The following methods are examples thereof.
          long days1 = start.until(end, ChronoUnit.DAYS);
          long days2 = ChronoUnit.DAYS.between(start, end);
         }
}

Intro

LocalTime is an immutable class and thread-safe, also seen as hour-min-sec, used to represent time. Time is measured to precision in nanoseconds. The value “13:45.30.123456789” for example, can be stored in a LocalTime.

This class does not store or represent a date or time-zone. This is just a rundown of local time as seen on a wall clock. Without additional details like an offset or timezone, it can not reflect an instant in the time-line. This is a value-based class, equals method should be used for comparisons.

Fields

MAX – The maximum supported Local Time, ’23:59:59.999999999′. MIDNIGHT, MIN, NOON

Important Static Methods

now(), now(Clock clock), now(ZoneId zone), parse(CharSequence text)

Important Instance Methods

isAfter(LocalTime other), isBefore(LocalTime other), minus(TemporalAmount amountToSubtract), minus(long amountToSubtract, TemporalUnit unit), plus(TemporalAmount amountToAdd), plus(long amountToAdd, TemporalUnit unit)

ZoneId zone = ZoneId.of("Asia/Kolkata");
LocalTime now = LocalTime.now();
LocalTime now1 = LocalTime.now(zone);
LocalTime then = LocalTime.parse("04:16:40");

Time difference can be measured in any of the following ways

long timeDiff = Duration.between(now, now1).toMinutes();
long timeDiff1 = java.time.temporal.ChronoUnit.MINUTES.between(now2, now1);

You can add/subtract hours, minutes, or seconds from any LocalTime entity, too.

minusHours(long hoursToSubtract), minusMinutes(long hoursToMinutes), minusNanos(long nanosToSubtract),
minusSeconds(long secondsToSubtract), plusHours(long hoursToSubtract), plusMinutes(long hoursToMinutes), plusNanos(long nanosToSubtract), plusSeconds(long secondsToSubtract)

now.plusHours(1L);
now1.minusMinutes(20L);

Related Article: Usage of various classes of Date Time API

Java LocalTime Modification

You can add hours, minutes, seconds and nanoseconds: 

LocalTime time = LocalTime.now();
LocalTime addHours = time.plusHours(5); // Add 5 hours
LocaLTime addMinutes = time.plusMinutes(15) // Add 15 minutes
LocalTime addSeconds = time.plusSeconds(30) // Add 30 seconds
LocalTime addNanoseconds = time.plusNanos(150_000_000) // Add 150.000.000ns (150ms)

Time Zones and their time difference

import java.time.LocalTime;
import java.time.ZoneId;
import java.time.temporal.ChronoUnit;
public class Test {
     public static void main(String[] args)
     {
           ZoneId zone1 = ZoneId.of("Europe/Berlin");
           ZoneId zone2 = ZoneId.of("Brazil/East");

           LocalTime now = LocalTime.now();
           LocalTime now1 = LocalTime.now(zone1);
           LocalTime now2 = LocalTime.now(zone2);

           System.out.println("Current Time : " + now);
           System.out.println("Berlin Time : " + now1);
           System.out.println("Brazil Time : " + now2);     
           long minutesBetween = ChronoUnit.MINUTES.between(now2,             now1);
           System.out.println("Minutes Between Berlin and Brazil : " + minutesBetween +"mins");
           }
}

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