DateTimeFormatterBuilder usages in Java 8, specifically optionals

Question

I'm trying to move from Joda to Java 8's ZonedDateTime and I'm hitting a wall with the DateTimeFormatterBuilder that I cannot seem to work around.

I want to accept any of these formats:

2013-09-20T07:00:33
2013-09-20T07:00:33.123
2013-09-20T07:00:33.123+0000
2013-09-20T07:00:33.123Z
2013-09-20T07:00:33.123Z+0000
2013-09-20T07:00:33+0000

Here is my current builder:

DateTimeFormatter formatter = new DateTimeFormatterBuilder()
        .parseCaseInsensitive()
        .append(DateTimeFormatter.ISO_LOCAL_DATE_TIME)
        .optionalStart()
        .appendPattern(".SSS")
        .optionalEnd()
        .optionalStart()
        .appendZoneId()
        .optionalEnd()
        .optionalStart()
        .appendPattern("Z")
        .optionalEnd()
        .toFormatter();

I'm probably wrong, but it appears that should match the patterns I want... right?

If anyone could point of what I may have missed, it'd be appreciated. I'm also not too sure of the use of appendOffset, so clarity on that is also appreciated if it turns out to be the answer.

Edit:

Text '2013-09-20T07:00:33.061+0000' could not be parsed at index 23

Looking at the builder, this appears to match due to the optional stages?

Edit 2:

After seeing advice from the first answer, I tried this:

DateTimeFormatter formatter = new DateTimeFormatterBuilder()
        .parseCaseInsensitive()
        .append(DateTimeFormatter.ISO_LOCAL_DATE_TIME)
        .optionalStart()
        .appendPattern(".SSS")
        .optionalEnd()
        .optionalStart()
        .appendZoneOrOffsetId()
        .optionalEnd()
        .toFormatter()

It continues to fail on the string above.

Edit 3:

Latest tests result in this exception:

java.time.format.DateTimeParseException: Text '2013-09-20T07:00:33.061+0000' could not be parsed at index 23
at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1947)
at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1849)
at java.time.ZonedDateTime.parse(ZonedDateTime.java:597)
at java.time.ZonedDateTime.parse(ZonedDateTime.java:582)

Answer 1

It may be the reason that +0000 is not a zone id, but a zone offset.

the documentation offers this list:

  Symbol       Meaning                     Presentation      Examples
  ------       -------                     ------------      -------
       V       time-zone ID                zone-id           America/Los_Angeles; Z; -08:30
       z       time-zone name              zone-name         Pacific Standard Time; PST
       O       localized zone-offset       offset-O          GMT+8; GMT+08:00; UTC-08:00;
       X       zone-offset 'Z' for zero    offset-X          Z; -08; -0830; -08:30; -083015; -08:30:15;
       x       zone-offset                 offset-x          +0000; -08; -0830; -08:30; -083015; -08:30:15;
       Z       zone-offset                 offset-Z          +0000; -0800; -08:00;

You may use appendOffset("+HHMM", "0000") (doc) or appendZoneOrOffsetId() (doc) instead of appendZoneId().

so your full formatter may look like the following

DateTimeFormatter formatter = new DateTimeFormatterBuilder()
                .parseCaseInsensitive()
                .append(DateTimeFormatter.ISO_LOCAL_DATE_TIME)
                .optionalStart()
                .appendPattern(".SSS")
                .optionalEnd()
                .optionalStart()
                .appendZoneOrOffsetId()
                .optionalEnd()
                .optionalStart()
                .appendOffset("+HHMM", "0000")
                .optionalEnd()
                .toFormatter();

Further the way of creating a ZonedDateTime may influence if there is an exception or not. Therefore I'd recommend the following as this worked without any exceptions.

LocalDateTime time = LocalDateTime.parse("2013-09-20T07:00:33.123+0000", formatter);
ZonedDateTime zonedTime = time.atZone(ZoneId.systemDefault());