How do I get my hour, minutes, seconds, and milliseconds to be zeros?

Question

I'm trying to get my format to be 2016-07-08T00:00:00.000Z.

String myDate = "20160708";
LocalDate myLocalDate = LocalDate.parse(myDate, DateTimeFormatter.BASIC_ISO_DATE);
OffsetDateTime myOffsetDate = myLocalDate.atTime(OffsetTime.now(ZoneOffset.UTC));

System.out.println(myOffsetDate); //2016-07-08T14:58:23.170Z

Answer 1

Well don't say "I want it to use the current time"! That's what this is doing:

OffsetTime.now(ZoneOffset.UTC)

If you just want an OffsetDateTime from a LocalDate by providing a zero offset and midnight, you can use:

OffsetDateTime myOffsetDate = myLocalDate
    .atTime(LocalTime.MIDNIGHT)
    .atOffset(ZoneOffset.UTC);

Or if you prefer:

OffsetDateTime myOffsetDate = myLocalDate
    .atTime(OffsetTime.of(LocalTime.MIDNIGHT, ZoneOffset.UTC));

(Personally I prefer the first version, myself...)

Note that that's just getting you the right OffsetDateTime. If you want to format that with milliseconds and seconds, you'll need to do that explicitly:

DateTimeFormatter formatter = DateTimeFormatter
    .ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSSX");
System.out.println(myOffsetDate.format(formatter));

As noted in comments, if you're find with a ZonedDateTime instead of an OffsetDateTime, you can use

ZonedDateTime myOffsetDate = myLocalDate.atStartOfDay(ZoneOffset.UTC);