Parse String datetime with Zone with Java Date

Question

I am trying to parse these dates in java.time and then get a String representation.

2021-12-27T09:15:09.738+02:00
2022-01-11T20:04:21+02:00

I read this similar answer and I have created a method in order to parse the above dates and return a String with the desired format:

public String getDatetimeFromDatetimeWithT(String dateFull) {
    String date = "";
    
    try {
        LocalDateTime ldate = LocalDateTime.parse(dateFull, DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSSZ"));
        date = ldate.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
    } catch (Exception e) {
        System.out.println(dateFull + " not matched 1 " + e);
    }

    try {
        LocalDateTime ldate = LocalDateTime.parse(dateFull, DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ssZ"));
        date = ldate.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
    } catch (Exception e) {
       System.out.println(dateFull + " not matched 2" + e);
    }
    
    return date;
}

However, none patterns are matched. What I am missing here?

UPDATE: In both dates I get an exception for the + character.

2021-12-27T09:15:09.738+02:00 not matched 1 java.time.format.DateTimeParseException: Text '2021-12-27T09:15:09.738+02:00' could not be parsed at index 23

2022-01-11T20:04:21+02:00 not matched 2 java.time.format.DateTimeParseException: Text '2022-01-11T20:04:21+02:00' could not be parsed at index 19

You are using an OffsetDateTime representation where a ZonedDateTime might be assumed. Use ZonedDateTime. — Joop Eggen, Jan 12 '22 at 10:04

deHaar · Accepted Answer · 2022-01-12T10:10:55.470

You don't even need to define a pattern, your examples are ISO formatted and they contain an offset rather than a zone.

That's why you can use this alternative (if you want to stick to LocalDateTime):

// parse without passing a formatter
OffsetDateTime odtA = OffsetDateTime.parse("2021-12-27T09:15:09.738+02:00");
OffsetDateTime odtB = OffsetDateTime.parse("2022-01-11T20:04:21+02:00");
// extract the LocalDateTimes
LocalDateTime ldtA = odtA.toLocalDateTime();
LocalDateTime ldtB = odtB.toLocalDateTime();
// print them
System.out.println(ldtA);
System.out.println(ldtB);

Result:

2021-12-27T09:15:09.738
2022-01-11T20:04:21

To make your method shorter, write something like this:

public static String getDatetimeFromDatetimeWithT(String dateFull) throws DateTimeParseException {
    return OffsetDateTime.parse(dateFull)
                         .format(DateTimeFormatter.ISO_LOCAL_DATE_TIME);
}

This basically parses the String argument to an OffsetDateTime and formats that OffsetDateTime using only the information a LocalDateTime has.

Result stays the same as posted above…

score 1 · Answer 2 · answered Jan 12 '22 at 09:52

1

Your date pattern is not correct. Use this:

yyyy-MM-dd'T'HH:mm:ss.SSSXXX

Or use one of the predefined ISO standard classes to do the parsing for you:

DateTimeFormatter.ISO_ZONED_DATE_TIME.parse(dateFull);

answered Jan 12 '22 at 09:52

Renis1235

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Could you write how to use `DateTimeFormatter.ISO_ZONED_DATE_TIME.parse(dateFull);` ? I tried to replace it in ` LocalDateTime ldate = LocalDateTime.parse(dateFull, DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ssZ"));` but it isn't valid. – yaylitzis Jan 12 '22 at 09:59
What date string are you using? Because it works in my test environment. – Renis1235 Jan 12 '22 at 10:04
1

You can't use LocalDateTime as it doesn't track the time zone. You need to use ZonedDateTime or OffsetDateTime. (See my answer) – Michael Gantman Jan 12 '22 at 10:17

score 0 · Answer 3 · answered Jan 12 '22 at 10:16

LocalDateTime doesn't contain time zone info. For that you need to use either ZonedDateTime or OffsetDateTime class. You still can (and should IMHO) use DateTimeFormatter. There is predefined formatter there called ISO_OFFSET_DATE_TIME that should fit your needs. Also a while ago I needed to parse a date from a string when format was not known in advance. So, I wrote an article about my implementation idea. You can read it here

Parse String datetime with Zone with Java Date

3 Answers3