Group long UTC by day

Question

Is there any reasonable way to group long UTC dates by day?

I would change them to 86400, but it does not take a second per second.

Does anyone have any other ideas, I use java, so I can parse them into Date Objects, but I'm a bit concerned about the overhead of performance on using a date class.

There is also a more efficient way than comparing the parts of the month and day of the year of a Date object?

Answer 1

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Answer 2

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Answer 3

TL;DR

Instant.ofEpochSecond( 1_493_367_302L )            // Convert a count of whole seconds from epoch of 1970 into a date-time value in UTC.
       .atZone( ZoneId.of( "Pacific/Auckland" ) )  // Adjust into the time zone as a context for determining a date.
       .toLocalDate()                              // Extract a date-only value by which we can sort/collect/organize our date-time values.

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1970-01-01T00:00:00, Instant.

Instant instant = Instant.ofEpochSecond( 1_493_367_302L ) ;

instant.toString(): 2017-04-28T08: 15: 02Z

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continent/region, America/Montreal, Africa/Casablanca Pacific/Auckland. 3-4 , EST IST, , (!).

ZoneId z = ZoneId.of( "America/Montreal" ); 
ZonedDateTime zdt = instant.atZone( z );

zdt.toString(): 2017-04-28T01:15: 02-07: 00 [America/Los_Angeles]

ZonedDateDate . LocalDate. LocalDate .

LocalDate ld = zdt.toLocalDate();

ld.toString(): 2017-04-28

, Map LocalDate List Set ZonedDateTime . Streams .

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• Java SE 8, Java SE 9,
  • .
  • Java API .
  • Java 9 .
• Java SE 6 Java SE 7
  • java.time Java 6 7 ThreeTen-Backport.
• Android
  • The ThreeTenABP project adapts ThreeTen-Backport (mentioned above) specifically for Android.
  • See. How to use ... ThreeTenABP .

The ThreeTen-Extra project extends java.time with additional classes. This project is proof of possible future additions to java.time. Here you can find useful classes, such as Interval, YearWeek, YearQuarterand longer .