Getting days between current date and other date in Java

Question

I need a method which returns the difference in days between the current day and other any date, I have the following:

private long getDays(Date dateOp) {
    Calendar feCurrent=Calendar.getInstance();
    feCurrent.set(Calendar.HOUR_OF_DAY, 0);
    feCurrent.set(Calendar.MINUTE, 0);
    feCurrent.set(Calendar.SECOND, 0);

    Calendar feAna=Calendar.getInstance();
    feAna.setTime(dateOp);
    feAna.set(Calendar.HOUR_OF_DAY, 0);
    feAna.set(Calendar.MINUTE, 0);
    feAna.set(Calendar.SECOND, 0);
    feAna.getTime());
    long timeDiff = Math.abs(feAna.getTime().getTime() - feCurrent.getTime().getTime());

    return TimeUnit.MILLISECONDS.toDays(timeDiff);
}

The thing is I'm always getting one day less, for example, if the date as parameter is Octuber 16th 2017, the result will 3, but it's actually four, I debugged and the timeDiff for those dates is 345599395 , when converted to days is 3.999....

Does anyone have idea why it's not working.

By the way the date as parameter is load from a database, because if I tried with a main setting both dates it works.

Answer 1

You can use java.time components if you use Java 8

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

final class PeriodTest {

    public static void main(String[] args) {
        LocalDate now = LocalDate.of(2017, 4, 4); // 2017-04-04
        LocalDate otherDate = LocalDate.of(2015, 10, 23); // 23-10-2015
        long days = Math.abs(ChronoUnit.DAYS.between(otherDate, now));

        System.out.println("Days = " + days);
    }
}

Output

Days = 529

Pros:

• you don't have to play with old Calendar object
• you can convert java.util.Date to java.time.Instant with Date.toInstant() method to get it working with current example

Java 6 solution

For Java 6 you can use Joda-Time that was a precursor of Java 8 Time API.

import org.joda.time.Days;
import org.joda.time.LocalDate;

final class PeriodTest {

    public static void main(String[] args) {
        LocalDate now = LocalDate.parse("2017-04-04");
        LocalDate otherDate = LocalDate.parse("2015-10-23");

        int days = Math.abs(Days.daysBetween(now, otherDate).getDays());

        System.out.println("Days = " + days);
    }
}