CODEWITHSUNDEEP
javadatetimeunix-timestampjava-timecurrent-time
Bing Hao
Bing Hao

Reputation: 17

How to convert the Integer timestamp to date format and compare with LocalDateTime.now?

I have receive a timestamp in request as Integer format

target_time = 1728962183

Then I want to use it to compare with LocalDateTime.now() to decide the code flow.

Exp:

if(target_time < LocalDateTime.now()) {
   // perform some action
}

How do I convert the Integer timestamp to Date format?

Upvotes: -2

Views: 59

Answers (1)

Basil Bourque
Basil Bourque

Reputation: 338516

tl;dr

Instant
.ofEpochSecond ( 1_728_962_183L )
.isBefore( Instant.now() )

Epoch reference

If you know that number to be a count of whole seconds since the epoch reference of first moment of 1970 in UTC (1970-01-01T00:00Z), then convert to an Instant.

Instant

long count = 1_728_962_183L;
Instant instant = Instant.ofEpochSecond ( count );

instant.toString() = 2024-10-15T03:16:23Z

Compare to the current moment to see if that moment has passed.

boolean isPast = instant.isBefore( Instant.now() ) ;

LocalDateTime is the wrong class

You asked:

compare with LocalDateTime.now(

The LocalDateTime class represents a date with time-of-day, but lacks the context of a time zone or offset-from-UTC. Without that context, a date-with-time is ambiguous. We don't know if that was the date and time in Tokyo Japan, or in Toulouse France, or in Toledo Ohio US – three very different moments, several hours apart.

So the LocalDateTime class cannot represent a moment, is not a point on the timeline. So it makes no sense to compare a LocalDateTime to a moment.

Represent a moment

Three classes in java.time represent a moment. They provide three different ways to look at a moment.

  • Instant
    A moment as seen in UTC, that is, with an offset of zero hours-minutes-seconds from the temporal meridian of UTC. This class is the basic building-block of java.time framework.
  • OffsetDateTime
    A moment as seen through an offset, some number of hours-minutes-seconds ahead or behind the temporal meridian of UTC.
  • ZonedDateTime
    A moment as seen through a particular time zone.

An offset is merely a number of hours-minutes-seconds. A time zone is much more. A time zone is a named history of the past, present, and future changes to the offset used by the people of a particular region, as decided by their politicians.

Upvotes: 1

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