Java 8 – How to find difference between two LocalDateTime using Period/Duration ?

August 11, 2022 SJ Java 8, Java 8 Date/Time 0

In this article, we will learn how to find difference between two LocalDateTime and Calendar/Date instances

1. Find difference between two LocalDateTime instances :

  • To find difference between two LocalDateTime instances, first we need to segregate LocalDate and LocalTime as there is no way to find difference between them directly
  • To segregate Date and Time parts separately, we can use toLocalDate() and toLocalTime() methods of LocalDateTime
    • toLocalDate() – gets the LocalDate part of invoking LocalDateTime
    • toLocalTime() – gets the LocalTime part of invoking LocalDateTime
  • Use Period.between() method to find difference between 2 LocalDate instances
    • Period.between accepts 2 input-arguments and returns difference of two LocalDate,
      1. Pass organization joining date as 1st argument
      2. Pass organization relieving date as 2nd argument
    • Period class has many useful method like,
      1. getYears() – returns numbers of years between 2 LocalDate instances
      2. getMonths() – returns numbers of months between 2 LocalDate instances
      3. getDays() – returns numbers of days between 2 LocalDate instances
  • Similarly, use Duration.between() method to find difference between 2 LocalTime instances
    • Duration.between accepts 2 input-arguments and returns difference of two LocalTime,
      1. Pass office start time as 1st argument
      2. Pass office end time as 2nd argument
    • Duration class has many useful methods like,
      1. getSeconds() – Gets the number of seconds in this duration between 2 LocalTime instances
      2. getNano() – Gets the number of nanoseconds within the second in this duration between 2 LocalTime instances
  • Finally print Time Period/Duration spent in an organization to the console

FindDifferenceOfTwoLocalDateTime.java

package in.bench.resources.java8.localdatetime.examples;

import java.time.Duration;
import java.time.LocalDateTime;
import java.time.Period;

public class FindDifferenceOfTwoLocalDateTime {

	public static void main(String[] args) {

		// 1. organization joining date
		LocalDateTime joiningLocalDateTime = LocalDateTime.of(2017, 3, 6, 10, 32, 56, 123456789);
		System.out.println("Organization Joining Date/time is :- \n" + joiningLocalDateTime);


		// 2. organization relieving date
		LocalDateTime relievingLocalDateTime = LocalDateTime.of(2019, 6, 28, 20, 31, 43, 987654321);
		System.out.println("\nOrganization Relieving Date/time is :- \n" + relievingLocalDateTime);


		// 3. difference between 2 LocalDate - Days spent in a organization
		Period period = Period.between(
				joiningLocalDateTime.toLocalDate(), 
				relievingLocalDateTime.toLocalDate()
				);
		System.out.println("\nPeriod between 2 LocalDate is :- \n" + period);


		// 3.1 get difference of years/months/days
		int years = period.getYears();
		int months = period.getMonths();
		int days = period.getDays();


		// 4. difference between 2 LocalTime - Time duration spent in Office
		Duration duration = Duration.between(
				joiningLocalDateTime.toLocalTime(), 
				relievingLocalDateTime.toLocalTime()
				);
		System.out.println("\nTime Duration between 2 LocalTime is :- \n" + duration);


		// 4.1 get difference in nanos/seconds
		int nanos = duration.getNano();
		long seconds = duration.getSeconds();


		// 5. print to console
		System.out.print("\nPeriod & Time Duration spent in an Organization is :- \n"
				+ years + " Years " 
				+ months + " Months " 
				+ days + " Days "
				+ seconds + " Seconds "
				+ nanos + " Nanos");
	}
}

Output:

Organization Joining Date/time is :- 
2017-03-06T10:32:56.123456789

Organization Relieving Date/time is :- 
2019-06-28T20:31:43.987654321

Period between 2 LocalDate is :- 
P2Y3M22D

Time Duration between 2 LocalTime is :- 
PT9H58M47.864197532S

Period & Time Duration spent in an Organization is :- 
2 Years 3 Months 22 Days 35927 Seconds 864197532 Nanos

2. Find difference between two Calendar/Date instances :

  • First, get organization joining Date/time by instantiating GregorianCalendar and passing Year, Month, Day, Hour, Minute and Second fields/values to the constructor
  • Similarly, get 2nd Date/time as organization relieving Date by instantiating GregorianCalendar and passing Year, Month, Day, Hour, Minute and Second fields/values to the constructor
    • getTime() method of Date returns the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by this Date object
  • Subtract joining date/time from relieving date/time which returns difference between 2 Dates in terms of milliseconds
    • Using this difference in Milliseconds, calculate years, days, hours, minutes and seconds as shown in the below illustration
  • Finally print Years/Days/Hours/Minutes/Seconds spent in an organization to the console

FindDifferenceOfTwoCalendarDateTime.java

package in.bench.resources.java8.localdatetime.examples;

import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

public class FindDifferenceOfTwoCalendarDateTime {

	public static void main(String[] args) {

		// 1. organization joining date - Instantiate GregorianCalendar
		Calendar calendar1 = new GregorianCalendar(2017, 2, 6, 10, 32, 56); // March
		Date date1 = calendar1.getTime();
		System.out.println("Organization Joining Date/time is :- \n" + date1);


		// 2. organization relieving date - Instantiate GregorianCalendar
		Calendar calendar2 = new GregorianCalendar(2019, 5, 28, 20, 31, 43); // June
		Date date2 = calendar2.getTime();
		System.out.println("\nOrganization Relieving Date/time is :- \n" + date2);


		// 3. difference between 2 Date/time - Days spent in a organization
		long differenceInMillis = date2.getTime() - date1.getTime();


		// 3.1 get difference of years/days/hours/minutes/seconds
		long years = (differenceInMillis / (365 * 24 * 60 * 60 * 1000L)); 
		long days = (differenceInMillis / (24 * 60 * 60 * 1000L)) % 365;
		long hours = (differenceInMillis / (60 * 60 * 1000L)) % 24;
		long minutes = (differenceInMillis / (60 * 1000L)) % 60;
		long seconds = (differenceInMillis / 1000) % 60;   


		// 3.2 print to console
		System.out.print("\nTime Duration spent in an Office is :- \n"
				+ years + " Years " 
				+ days + " Days "
				+ hours + " Hours " 
				+ minutes + " Minutes "
				+ seconds + " Seconds"
				);
	}
}

Output:

Organization Joining Date/time is :- 
Mon Mar 06 10:32:56 IST 2017

Organization Relieving Date/time is :- 
Fri Jun 28 20:31:43 IST 2019

Time Duration spent in an Office is :- 
2 Years 114 Days 9 Hours 58 Minutes 47 Seconds

Related Articles:

References:

Happy Coding !!
Happy Learning !!

Java 8 – What are all the Temporal Fields supported by LocalDateTime ?
Java 8 – How to compare two LocalDateTime instances ?

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