Java: ZonedDateTime - parse timestring without timezone

Question

I have a datetime-string WITHOUT a specified timezone. But I want to parse it with ZonedDateTime to give it a timezone-meaning in the act of parsing.

This code is working but uses LocalDateTime for parsing - and then convert it to ZonedDateTime with giving it a timezone-meaning.

DateTimeFormatter dtf = DateTimeFormatter.ofPattern ("yyyyMMddHHmm");

String tmstr = "201810110907";

LocalDateTime tmp = LocalDateTime.parse (tnstr,dtf);
ZonedDateTime mytime = ZonedDateTime.of (tmp, ZoneId.of ("UTC"));

Is there a way I can parse it directly with ZonedDateTime?

I have tried this, but it was not working.

mytime = mytime.withZoneSameInstant(ZoneId.of("UTC")).parse(str,dtf);

Answer 1

You may specify a default time zone on the formatter:

    DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyyMMddHHmm")
            .withZone(ZoneId.of("UTC"));
    String tmstr = "201810110907";
    ZonedDateTime mytime = ZonedDateTime.parse(tmstr, dtf);
    System.out.println(mytime);

Output:

2018-10-11T09:07Z[UTC]

Bonus tip: Rather than ZoneId.of("UTC") it’s usually nicer to use ZoneOffset.UTC. If you accept the output being printed as 2018-10-11T09:07Z instead (Z meaning UTC).