Java Localize DateFormat Cannot format given Object as a Date

Question

I wish to get a localized date string. For that, I'm doing:

String dateString = "2019-06-01 00:15:00";
dateString = dateString.replace(" ", "T");
dateString = dateString.concat("Z");

DateFormat dateformat = DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.MEDIUM, Locale.FRENCH);
System.out.println(dateformat.format(dateString));

But I'm getting the following exception:

java.lang.IllegalArgumentException: Cannot format given Object as a Date

What could be wrong here?

I recommend you don’t use `DateFormat`. That class is notoriously troublesome and long outdated. Instead use `DateTimeFormatter` from [java.time, the modern Java date and time API](https://docs.oracle.com/javase/tutorial/datetime/). — Ole V.V., Aug 06 '19 at 13:23
@OleV.V. Can you provide a sample for localization using DateTimeFormatter? — user5155835, Aug 06 '19 at 13:24
Isn't DateFormat.format suppose to format a date object to a string? Not the other way around? — KnotGillCup, Aug 06 '19 at 13:26
@OleV.V. If you could make your comment an answer, I can mark it as answer — user5155835, Aug 06 '19 at 15:42
@user5155835, date formatter can't do that. You will have to parse date from your string first, then format the date. — M. Prokhorov, Aug 06 '19 at 15:50
@user5155835 I have only hesitatingly done that. I still tend to consider this question a duplicate, so you may find better answers by searching for questions like it. — Ole V.V., Aug 06 '19 at 16:03

score 1 · Accepted Answer · answered Aug 06 '19 at 15:51

java.time

    String dateString = "2019-06-01 00:15:00";
    dateString = dateString.replace(" ", "T");
    dateString = dateString.concat("Z");

    DateTimeFormatter formatter = DateTimeFormatter
            .ofLocalizedDateTime(FormatStyle.SHORT, FormatStyle.MEDIUM)
            .withLocale(Locale.FRENCH);
    OffsetDateTime dateTime = OffsetDateTime.parse("2019-06-01T00:15:00Z");
    String formattedDateTime = dateTime.format(formatter);

    System.out.println("Formatted date/time: " + formattedDateTime);

Output:

Formatted date/time: 01/06/2019 00:15:00

I recommend you don’t use DateFormat. That class is notoriously troublesome and long outdated. Instead use DateTimeFormatter from java.time, the modern Java date and time API, as shown in my code.

For what went wrong in your code please see the similar question that I link to at the bottom.

Links

Oracle tutorial: Date Time explaining how to use java.time.
Similar question: Java : Cannot format given Object as a Date. My answer to the same.

Java Localize DateFormat Cannot format given Object as a Date

1 Answers1

java.time

Links