Converting difference between 2 dates to days in java 7

Question

I want to compare 2 dates in java and need to convert the difference between the 2 dates to days

//Setting up date
Calendar cal = Calendar.getInstance();
cal.set(2019, 5, 16);
Date d = cal.getTime();

Output would be something like this : Sun Jun 16 11:04:57 UTC 2019

//Getting the current date instance
Calendar cal1 = Calendar.getInstance();
Date d1 = cal1.getTime();

Output would be something like this : Mon Jul 08 11:04:57 UTC 2019

Need to get the difference between d & d1 in days.

Thanks in advance for taking your time to provide solution

Use the new time and date methods. Calendar should never be used in new code. — Thorbjørn Ravn Andersen, Jul 08 '19 at 16:49
This is really complicated to get right with the old `Calendar` class. Do consider [ThreeTen Backport](https://www.threeten.org/threetenbp/), the backport to Java 6 and 7 of java.time, the modern Java date and time API. With it it will be a piece of cake and give very readable code. — Ole V.V., Jul 08 '19 at 17:53
Answer using ThreeTen Backport: `ChronoUnit.DAYS.between(LocalDate.of(2019, Month.JUNE, 16), LocalDate.now(ZoneId.of("Asia/Kolkata")))`. Just now gave 22. Please factor out into an appropriate number of lines of code. — Ole V.V., Jul 08 '19 at 17:58

score 1 · Accepted Answer · answered Jul 08 '19 at 16:25

Here, you just have to do simple math.

Calendar start = Calendar.getInstance();
Calendar end = Calendar.getInstance();
start.set(2010, 7, 23);
end.set(2010, 8, 26);
Date startDate = start.getTime();
Date endDate = end.getTime();
long startTime = startDate.getTime();
long endTime = endDate.getTime();
long diffTime = endTime - startTime;
long diffDays = diffTime / (1000 * 60 * 60 * 24);
DateFormat dateFormat = DateFormat.getDateInstance();
System.out.println("The difference between "+
  dateFormat.format(startDate)+" and "+
  dateFormat.format(endDate)+" is "+
  diffDays+" days.");

This will not work when crossing daylight savings time (or leap seconds) and might as well not give the expected results when using different times of day. You can modify it like this:

start.add(Calendar.DAY_OF_MONTH, (int)diffDays);
while (start.before(end)) {
    start.add(Calendar.DAY_OF_MONTH, 1);
    diffDays++;
}
while (start.after(end)) {
    start.add(Calendar.DAY_OF_MONTH, -1);
    diffDays--;
}

Hope this helps. Good luck.

score 1 · Answer 2 · answered Jul 08 '19 at 16:26

1

Simplest way:

public static long getDifferenceDays(Date d, Date d1) {
    long diff = d1.getTime() - d.getTime();
    return TimeUnit.DAYS.convert(diff, TimeUnit.MILLISECONDS);
}

answered Jul 08 '19 at 16:26

dbz

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Converting difference between 2 dates to days in java 7

2 Answers2