Subtract two dates in Java

Question

Possible Duplicate:
Calculating the Difference Between Two Java Date Instances

I know this might be a duplicate thread. But I am trying to figure out a way to compute the difference between two dates. From jquery the date string is in the format 'yyyy-mm-dd'. I read this as a String and converted to java Date like this

Date d1 = new SimpleDateFormat("yyyy-M-dd").parse((String) request.getParameter(date1));
Date d2 = new SimpleDateFormat("yyyy-M-dd").parse((String) request.getParameter(date2));

I want to compute the difference in the number of days between these two dates.

Note: I cannot use third party API's as those need to reviewed.

Which difference? Depending on the locality etc. there are multiple definitions. Take a look at the various 3rd party time API's to see where I'm heading with this comment. — Maarten Bodewes, Oct 23 '12 at 19:23
If you think it is a dup, why not search for it? It's not like the other thread cannot be found... — Maarten Bodewes, Oct 23 '12 at 19:25
@owlstead I cannot use third party apps because it needs to be reviewed by legal team to get it approved. So I have to tinker with what is available in util package. — user525146, Oct 23 '12 at 19:27
@owlstead. Shouldn't the difference in number of days which OP needs be same in all cases? — Rohit Jain, Oct 23 '12 at 19:29
@user525146 You should add your constraints to the question by editing it. It appears that the most commonly recommended solution is to use third party tools. If you can't, this should be stated up front. — Thomas Owens, Oct 23 '12 at 19:31

uldall · Accepted Answer · 2018-05-28T15:29:27.710

37

Edit 2018-05-28 I have changed the example to use Java 8's Time API:

LocalDate d1 = LocalDate.parse("2018-05-26", DateTimeFormatter.ISO_LOCAL_DATE);
LocalDate d2 = LocalDate.parse("2018-05-28", DateTimeFormatter.ISO_LOCAL_DATE);
Duration diff = Duration.between(d1.atStartOfDay(), d2.atStartOfDay());
long diffDays = diff.toDays();

edited May 28 '18 at 15:29

answered Oct 23 '12 at 19:44

uldall

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This will fail across spring's daylight savings boundary. Example (using your code), `d1 = new Date(112, 3-1, 11, 0, 0, 0)`, `d2 = new Date(112, 3-1, 12, 0, 0, 0)`, results in `0`. – Steve Kuo Oct 23 '12 at 22:14
1

The answer provides a truncated result. For a rounded result: long diffDays = (diff + 12 * 60 * 60 * 1000) / (24 * 60 * 60 * 1000) – Giorgio Barchiesi Nov 14 '13 at 10:47
@SteveKuo, I know this was a while ago, but do you have a better solution that doesn't fail for daylight savings? I'm not trying to be snarky, I am working on a similar issue myself and would prefer to avoid code with obvious flaws. – A Bailey Jun 19 '17 at 19:35
1

This failed for me with exception being: `java.time.temporal.UnsupportedTemporalTypeException: Unsupported unit: Seconds`. What worked for me was: `d1.until(d2).getDays()`, where both `d1` and `d2` are created as `LocalDate.of(...)`. – G. Urikh Jul 31 '20 at 12:43

score 13 · Answer 2 · answered Oct 23 '12 at 19:42

13

Assuming that you're constrained to using Date, you can do the following:

Date diff = new Date(d2.getTime() - d1.getTime());

Here you're computing the differences in milliseconds since the "epoch", and creating a new Date object at an offset from the epoch. Like others have said: the answers in the duplicate question are probably better alternatives (if you aren't tied down to Date).

answered Oct 23 '12 at 19:42

mnajera

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Please read the question again carefully. Your answer does **not** answer the original question. – DavidPostill Mar 15 '15 at 10:34
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doesn't matter because it helps when you are looking for solutions for yourself... This is the answer i will use for my own issue – Felipe Aug 02 '20 at 13:02

score 7 · Answer 3 · answered Oct 23 '12 at 19:44

7

Date d1 = new SimpleDateFormat("yyyy-M-dd").parse((String) request.
            getParameter(date1));
Date d2 = new SimpleDateFormat("yyyy-M-dd").parse((String) request.
            getParameter(date2));

long diff = d2.getTime() - d1.getTime();

System.out.println("Difference between  " + d1 + " and "+ d2+" is "
        + (diff / (1000 * 60 * 60 * 24)) + " days.");

answered Oct 23 '12 at 19:44

16dots

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Will fail across the start of daylight savings boundary. Example, d1=`2012-3-11` and d2=`2012-3-12` results in 0 days. – Steve Kuo Oct 23 '12 at 22:14

Subtract two dates in Java

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