I'm playing with date-time format from ISO 8601. I have this pattern:
"yyyy-MM-dd'T'HH:mm:ssZZ'Z'"
and the output is:
"2015-11-17T00:00:00+0000Z".
My question is if the output is ok, if is possible to have in a date +0000 and Z taking in account both has the same meaning time zone offset/id. Thanks in advance for clarification =)
No, the Z is an offset-from-UTC so it should not be combined redundantly with a numerical offset of +00:00 or +0000.
While I do not have access to a paid copy of the ISO 8601 spec, the Wikipedia page clearly states that the Z must follow the time-of-day:
…add a Z directly after the time without a space.
The freely-available RFC 3339, a profile of ISO 8601, defines a Z as being attached to a time-of-day:
A suffix … applied to a time …
The RFC also states with formal ABNF notation that we should use either a Z or a number. In ABNF, the slash (SOLIDUS) means “or” (exclusive ‘or’), while the pair of square brackets means “optional”.
time-numoffset = ("+" / "-") time-hour [[":"] time-minute]
time-zone = "Z" / time-numoffset
Furthermore, section 5.4 of the spec specifically recommends against including redundant information.
The modern java.time classes built into Java use the standard ISO 8601 formats by default when parsing/generating strings. See Oracle Tutorial.
With Z:
Instant instant = Instant.parse( "2019-01-23T12:34:56.123456789Z" ) ;
With +00:00:
OffsetDateTime odt = OffsetDateTime.parse( "2019-01-23T12:34:56.123456789+00:00" ) ;
To create a string with the Z, simply call Instant::toString.
String output = Instant.now().toString() ; // Capture the current moment in UTC, then generate text representing that value in standard ISO 8601 using the `Z` offset-indicator.
2019-05-22T21:00:52.214709Z
To create a string with the 00:00, call OffsetDateTime::format. Generate text using a DateTimeFormatter with a formatting pattern you define.
DateTimeFormatter f = DateTimeFormatter.ofPattern( "uuuu-MM-dd'T'HH:mm:ss.SSSxxx" ) ;
String output = OffsetDateTime.now( ZoneOffset.UTC ).format( f ) ;
2019-05-22T21:00:52.319076+00:00
You may want to truncate any microseconds or nanoseconds.
Instant
.now()
.truncatedTo( ChronoUnit.MILLIS )
.toString()
2019-05-22T21:11:28.970Z
…and…
OffsetDateTime
.now( ZoneOffset.UTC )
.truncatedTo( ChronoUnit.MILLIS )
.format(
DateTimeFormatter.ofPattern( "uuuu-MM-dd'T'HH:mm:ss.SSSxxx" )
)
2019-05-22T21:11:29.078+00:00
See this code running live at IdeOne.com.
