How do I find out whether a locale uses 12 or 24 hour time in Java?

Question

In Java, I want to print just the time of day in hours and minutes and want it to correctly switch between, e.g., \"13:00\" and \"1:00 PM\" according to the locale. How do I

Answer 1

I have written small function which detects whether current locale uses 24 or 12 hours:

public static boolean is24HourLocale() {
    String output = SimpleDateFormat.getTimeInstance(DateFormat.SHORT).format(new Date());
    if (output.contains(" AM") || output.contains(" PM")) {
        return false;
    } else {
        return true;
    }
}

Answer 2

The locale doesn't explicitly specify whether 12 or 24 hour time formats are preferred. Rather, locale specific date formats are handled by the locale defining the formats directly.

• If you simply want to use the "locale preferred" time format, just call one of the three DateFormat.getTimeInstance(...) static methods, and use whatever DateFormat it returns.

• If you have a SimpleDateFormat instance in your hands, you could (if you were prepared to do a significant amount of coding) call toPattern() and parse the resulting pattern to see if it used a 12 or 24 hour dates ... or neither. You could even tweak the pattern to use the "other" form and then call applyPattern(String) to alter the format.

Answer 3

Use the java.text.DateFormat class to create the correct output of the given time.

As from the API:

To format a date for the current Locale, use one of the static factory methods:

myString = DateFormat.getDateInstance().format(myDate);

You just use the getTimeInstance() method and call the format() method on the returned DateFormat object