Unable to obtain ZonedDateTime from TemporalAccessor when parsing a Date

Question

With Java 1.8.0_51 the following code (taken from Unable to obtain OffsetDateTime from TemporalAccessor)

DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyyMMdd").withZone(ZoneId.of("Europe/Berlin"));
OffsetDateTime offsetDateTime = ZonedDateTime.parse("20151113", formatter).toOffsetDateTime();
System.out.println(offsetDateTime.format(DateTimeFormatter.ISO_DATE));

throws an exception:

java.time.format.DateTimeParseException: Text '20151113' could not be parsed: Unable to obtain ZonedDateTime from TemporalAccessor: {},ISO,Europe/Berlin resolved to 2015-11-13 of type java.time.format.Parsed
at java.time.format.DateTimeFormatter.createError(DateTimeFormatter.java:1918)
at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1853)
at java.time.ZonedDateTime.parse(ZonedDateTime.java:597)

What am I doing wrong this time?

I have discussed the theory behind `java.time` at length here: https://stackoverflow.com/a/56508200/145989 — Ondra Žižka, Jun 08 '19 at 17:57

score 8 · Accepted Answer · edited May 23 '17 at 10:30

You are forgetting to set a time.

If you compare my answer with your code, you can notice that the only difference is that the time information missing. A ZonedDateTime contains a time information and since your current formatter does not handle it, an instance of ZonedDateTime can't be formed.

You can also see it in the stacktrace, that contains

Caused by: java.time.DateTimeException: Unable to obtain LocalTime from TemporalAccessor: {},ISO,Europe/Berlin resolved to 2015-11-13 of type java.time.format.Parsed
    at java.time.LocalTime.from(LocalTime.java:409)
    at java.time.ZonedDateTime.from(ZonedDateTime.java:560)
    ... 5 more

Depending on what you want, you could build a custom formatter with DateTimeFormatterBuilder and call parseDefaulting to provide a default values for each time chrono fields. If you want to default to midnight, you can set NANO_OF_DAY to 0. A sample example would be

public static void main(String[] args) {
    DateTimeFormatter formatter = 
        new DateTimeFormatterBuilder().appendPattern("yyyyMMdd")
                                      .parseDefaulting(ChronoField.NANO_OF_DAY, 0)
                                      .toFormatter()
                                      .withZone(ZoneId.of("Europe/Berlin"));

    OffsetDateTime offsetDateTime = ZonedDateTime.parse("20151113", formatter).toOffsetDateTime();
    System.out.println(offsetDateTime.format(DateTimeFormatter.ISO_DATE));
}

Another possible solution would be to parse the text as a LocalDate and then construct a ZoneDateTime with it:

public static void main(String[] args) {
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyyMMdd");
    LocalDate parsed = LocalDate.parse("20151113", formatter);
    ZonedDateTime zonedDateTime = ZonedDateTime.of(parsed, LocalTime.MIDNIGHT, ZoneId.of("Europe/Berlin"));
    // get OffsetDateTime similarly
}

So I cannot set a default time for my DateTimeFormatter as I can set a default time zone? — asmaier, Mar 11 '16 at 15:52
@asmaier Yes, this is `parseDefaulting` purpose. I edited with an example. — Tunaki, Mar 11 '16 at 15:53

score 2 · Answer 2 · answered Mar 11 '16 at 15:56

2

The Java 8 java.time.* package is a very strict package. It doesn't allow flexibility between types and inputs - if you want a ZonedDateTime object, you must construct it from an input that has a time zone, a date & a time.

If you want to use just a date to construct an object it has to be of a type that doesn't have a time field, specifically, LocalDate.

answered Mar 11 '16 at 15:56

Amit

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But a LocalDate does not have a timezone. And there is no `ZonedDate` only without a time. – Tunaki Mar 11 '16 at 15:58
@Tunaki - Correct. Personally I don't find it very comfortable to work with the package for these reasons exactly. It could be argued that "a date has no timezone", but practically it's useful at times... – Amit Mar 11 '16 at 16:03
1

I found a solution with LocalDate, too: `DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyyMMdd"); OffsetDateTime offsetDateTime = LocalDate.parse("20151113", formatter).atStartOfDay(ZoneId.of("Europe/Berlin")).toOffsetDateTime();` But I prefer the solution from @Tunaki, because all the configuration for the parsing is done via the formatter. – asmaier Mar 11 '16 at 16:16
@asmaier - that's OK. My answer explains the issue, it doesn't choose a solution. Choose the solution that works best for you... – Amit Mar 11 '16 at 16:19

Unable to obtain ZonedDateTime from TemporalAccessor when parsing a Date

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