Java Calendar: Subtract two Dates to get difference in days between the two

Question

I want to check how many days it has been since my user logged in:

Calendar lastLogin = Calendar.getInstance();
lastLogin.setTime(randomPlayer.getLastLogin());
Calendar today = Calendar.getInstance();

How would I subtract this to get the difference in days between the two? I.e number of days since last login.

It is highly recommended *not* to use the `Calendar` and `Date` classes anymore. If you're using Java 8, use `java.time`. If you're using an earlier version, use Joda-Time. `Calendar` and `Date` are really crufty, inefficient classes. — RealSkeptic, Apr 14 '17 at 12:55
You can use java time Period period= Period.between(date1, date2); then use period.getDays() to get day — Younes Ouchala, Apr 14 '17 at 13:05
that can be helpful for you http://www.javabrahman.com/quick-tips/java-8-how-to-calculate-difference-between-two-java-time-localdate-instances/ — Younes Ouchala, Apr 14 '17 at 13:09

Marvin · Accepted Answer · 2017-04-14T13:02:39.087

I suggest using LocalDate instead:

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

public class DaysBetween {

    public static void main(String[] args) {
        LocalDate lastLogin = LocalDate.of(2017, 4, 1);
        LocalDate today = LocalDate.now();
        System.out.println(daysBetween(lastLogin, today));
    }

    private static long daysBetween(LocalDate from, LocalDate to) {
        return ChronoUnit.DAYS.between(from, to);
    }
}

Or, if you really want to stick to Calendar:

import java.time.temporal.ChronoUnit;
import java.util.Calendar;

public class DaysBetween {

    public static void main(String[] args) {
        Calendar lastLogin = Calendar.getInstance();
        lastLogin.set(Calendar.YEAR, 2017);
        lastLogin.set(Calendar.MONTH, 3);
        lastLogin.set(Calendar.DAY_OF_MONTH, 1);
        Calendar today = Calendar.getInstance();
        System.out.println(daysBetween(lastLogin, today));
    }

    private static long daysBetween(Calendar from, Calendar to) {
        return ChronoUnit.DAYS.between(from.toInstant(), to.toInstant());
    }
}

Java Calendar: Subtract two Dates to get difference in days between the two

1 Answers1