Get a Period of Days between two Dates

Question

I use java.time.Period#getDays() to get the number of days for a given period of LocalDates.

It seems to work for most cases, but for a whole month, I get a period of zero days.

The following test case fails (java.lang.AssertionError: expected:<30> but was:<0>):

@Test
public void testOneMonthPeriodDays() {
    Period p = Period.between(LocalDate.of(2017, 06, 01), LocalDate.of(2017, 07, 01));
    assertEquals(30, p.getDays());
}

I'll bet p.getMonths() == 1. A `Period` is a count of years, months, and days. Your case would be one month and zero days. — GriffeyDog, May 01 '17 at 21:17

score 13 · Accepted Answer · edited Oct 28 '19 at 15:48

13

I believe this is the correct result. If you run the following test you will see that getMonths() returns 1. It seems that getDays is not get the total days but get the remainder days.

@Test
public void testOneMonthPeriodDays() {
    Period p = Period.between(LocalDate.of(2017, 06, 01), LocalDate.of(2017, 07, 01));
    assertEquals(0, p.getDays());
    assertEquals(1, p.getMonths());
}

To get the total number of days between two dates see this question Calculate days between two dates in Java 8

To quote the answer given in that question:

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

Note that DAYS is member of java.time.temporal.ChronoUnit enum.

edited Oct 28 '19 at 15:48

JuanMoreno

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answered May 01 '17 at 21:18

bhspencer

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Wouldn't it be better to show the link to that question since it already exists? – bhspencer May 01 '17 at 21:22
Sorry, I missed the link to the answer. Agreed. Yeah I think it looks better with the edit. Thanks. – Gray May 01 '17 at 21:24

score 7 · Answer 2 · answered May 01 '17 at 21:25

JavaDoc for java.time.Period#getDays() says:

returns the amount of days of this period, may be negative

I guess this is missleading and it does not really return the total amount of days.

I use now

final long daysElapsed = ChronoUnit.DAYS.between(LocalDate.of(2017, 06, 01), LocalDate.of(2017, 07, 01));

which works as expected.

score 1 · Answer 3 · edited Jul 29 '19 at 11:25

1

Do the following:

long daysDifference = DAYS.between(dayInitial, dayAfter);

where:

LocalDate dateInitial;   //initial date
LocalDate dateAfter;      //later date

edited Jul 29 '19 at 11:25

Vishwa Ratna

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answered May 01 '17 at 21:35

HaroldSer

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Get a Period of Days between two Dates

3 Answers3