Calculate days between two dates in Java 8

Question

I know there are lots of questions on SO about how to get, but I want and example using new Java 8 Date api. I also know JodaTime library, but I want a work way without external libraries.

Function needs to complain with these restrictions:

1. Prevent errors from date savetime
2. Input are two Date's objects (without time, I know localdatetime, but I need to do with date instances)

Answer 1

If you want logical calendar days, use DAYS.between() method from java.time.temporal.ChronoUnit:

LocalDate dateBefore;
LocalDate dateAfter;
long daysBetween = DAYS.between(dateBefore, dateAfter);

If you want literal 24 hour days, (a duration), you can use the Duration class instead:

LocalDate today = LocalDate.now()
LocalDate yesterday = today.minusDays(1);
// Duration oneDay = Duration.between(today, yesterday); // throws an exception
Duration.between(today.atStartOfDay(), yesterday.atStartOfDay()).toDays() // another option

For more information, refer to this document (and other documents re:Java 8 from Oracle).

Answer 2

Based on VGR's comments here is what you can use:

ChronoUnit.DAYS.between(firstDate, secondDate)

Answer 3

You can use until():

LocalDate independenceDay = LocalDate.of(2014, Month.JULY, 4);
LocalDate christmas = LocalDate.of(2014, Month.DECEMBER, 25);

System.out.println("Until christmas: " + independenceDay.until(christmas));
System.out.println("Until christmas (with crono): " + independenceDay.until(christmas, ChronoUnit.DAYS));

Answer 4

You can use DAYS.between from java.time.temporal.ChronoUnit

e.g.

import java.time.temporal.ChronoUnit;

public long getDaysCountBetweenDates(LocalDate dateBefore, LocalDate dateAfter) {
    return DAYS.between(dateBefore, dateAfter);
}

Answer 5

Use the DAYS in enum java.time.temporal.ChronoUnit . Below is the Sample Code :

Output : *Number of days between the start date : 2015-03-01 and end date : 2016-03-03 is ==> 368. **Number of days between the start date : 2016-03-03 and end date : 2015-03-01 is ==> -368*

package com.bitiknow.date;

import java.time.LocalDate;
import java.time.temporal.ChronoUnit;

/**
 * 
 * @author pradeep
 *
 */
public class LocalDateTimeTry {
    public static void main(String[] args) {

        // Date in String format.
        String dateString = "2015-03-01";

        // Converting date to Java8 Local date
        LocalDate startDate = LocalDate.parse(dateString);
        LocalDate endtDate = LocalDate.now();
        // Range = End date - Start date
        Long range = ChronoUnit.DAYS.between(startDate, endtDate);
        System.out.println("Number of days between the start date : " + dateString + " and end date : " + endtDate
                + " is  ==> " + range);

        range = ChronoUnit.DAYS.between(endtDate, startDate);
        System.out.println("Number of days between the start date : " + endtDate + " and end date : " + dateString
                + " is  ==> " + range);

    }

}

Answer 6

Everyone is saying to use ChronoUnit.DAYS.between but that just delegates to another method you could call yourself. So you could also do firstDate.until(secondDate, ChronoUnit.DAYS).

The docs for both actually mention both approaches and say to use whichever one is more readable.

Answer 7

If starDate and endDate are instance of java.util.Date, besides to @mohamed answer

Integer noOfDays = ChronoUnit.DAYS.between(startDate.toInstant(), endDate.toInstant());

but ChronoUnit.DAYS count days which completed 24 hours.

Answer 8

Here you go:

public class DemoDate {
    public static void main(String[] args) {
        LocalDate today = LocalDate.now();
        System.out.println("Current date: " + today);

        //add 1 month to the current date
        LocalDate date2 = today.plus(1, ChronoUnit.MONTHS);
        System.out.println("Next month: " + date2);

        // Put latest date 1st and old date 2nd in 'between' method to get -ve date difference
        long daysNegative = ChronoUnit.DAYS.between(date2, today);
        System.out.println("Days : "+daysNegative);

        // Put old date 1st and new date 2nd in 'between' method to get +ve date difference
        long datePositive = ChronoUnit.DAYS.between(today, date2);
        System.out.println("Days : "+datePositive);
    }
}

Answer 9

Get number of days before Christmas from current day , try this

System.out.println(ChronoUnit.DAYS.between(LocalDate.now(),LocalDate.of(Year.now().getValue(), Month.DECEMBER, 25)));

Answer 10

get days between two dates date is instance of java.util.Date

public static long daysBetweenTwoDates(Date dateFrom, Date dateTo) {
            return DAYS.between(Instant.ofEpochMilli(dateFrom.getTime()), Instant.ofEpochMilli(dateTo.getTime()));
        }

Answer 11

If the goal is just to get the difference in days and since the above answers mention about delegate methods would like to point out that once can also simply use -

public long daysInBetween(java.time.LocalDate startDate, java.time.LocalDate endDate) {
  // Check for null values here

  return endDate.toEpochDay() - startDate.toEpochDay();
}

Answer 12

I know this question is for Java 8, but with Java 9 you could use:

public static List<LocalDate> getDatesBetween(LocalDate startDate, LocalDate endDate) {
    return startDate.datesUntil(endDate)
      .collect(Collectors.toList());
}