Exception while converting XMLGregorianCalendar date 2022-11-24T13:35:00 into ISO

I have an XMLGregorianCalendar date in the below format:

2022-11-23T13:53:31

I want to convert it to ISO_8601 format like below:

2022-11-23T13:53:31.890Z

So I am getting below exception:

java.time.format.DateTimeParseException: Text '2022-11-23T13:53:31' could not be parsed at index 19

I have tried the below code:

public static boolean checkIfDateMatches( String fromDate, String toDate, String inputDate ) throws Exception {
    boolean flag = false;
    Date start = Date.from(Instant.parse(fromDate));
    Date end = Date.from(Instant.parse(toDate));
    Date input = Date.from(Instant.parse(inputDate));
    if( input.compareTo(start) >= 0 && input.compareTo(end) <= 0 ) {
        flag = true;
    }
    return flag;
}

Any help appreciated. Thank you

CodePudding user response：

If you just want to convert the example input to UTC, you will need to make sure it actually is UTC. Otherwise you would just append a Z and declare it UTC.

The DateTimeParseException tells you there's information missing in the String because a non existent index is attempted to be parsed. The input has a length of 19, so its last index is 18.

That means, in this case, the String cannot be (reliably) assigned to a zone or offset. Zone and offset are unkown. They have been expected at/from index 19.

If you can verify the input is a UTC time, you can use the following example that makes the input a comparable UTC datetime: An OffsetDateTime…

public static void main(String[] args) {
    // example input WITHOUT OFFSET
    String input = "2022-11-23T13:53:31";
    // parse it AND DECLARE IT UTC
    OffsetDateTime odt = LocalDateTime.parse(input)
                                      .atOffset(ZoneOffset.UTC);
    // print the result
    String msg = String.format("IN:  %s\nOUT: %s", 
                               input, 
                               odt.format(DateTimeFormatter.ISO_OFFSET_DATE_TIME));
    System.out.println(msg);
}

Output:

IN:  2022-11-23T13:53:31
OUT: 2022-11-23T13:53:31Z

You can compare OffsetDateTimes, just have a look at the docs.
If you need the milliseconds / fractions of second, define a custom DateTimeFormatter.

Remember to make sure the input is UTC.