Java Cookbook

Setting the Default Locale

Problem

You want to change the default Locale for all operations within a given Java runtime.

Solution

Set the system property user.language, or call Locale.setDefault( ) .

Discussion

Here is a program called SetLocale, which takes the language and country codes from the command line, constructs a Locale object, and passes it to Locale.setDefault( ). When run with different arguments, it prints the date and a number in the appropriate locale:

C:\javasrc\i18n>java SetLocale en US
6/30/00 1:45 AM
123.457

C:\javasrc\i18n>java SetLocale fr FR
30/06/00 01:45
123,457

The code is similar to the previous recipe in how it constructs the locale.

import java.text.*;
import java.util.*;

/** Change the default locale */
public class SetLocale {
    public static void main(String[] args) {

        switch (args.length) {
        case 0:
            Locale.setDefault(Locale.FRANCE);
            break;
        case 1:
            throw new IllegalArgumentException(  );
        case 2:
            Locale.setDefault(new Locale(args[0], args[1]));
            break;
        default:
            System.out.println("Usage: SetLocale [language [country]]");
            // FALLTHROUGH
        }

        DateFormat df = DateFormat.getInstance(  );
        NumberFormat nf = NumberFormat.getInstance(  );

        System.out.println(df.format(new Date(  )));
        System.out.println(nf.format(123.4567));
    }
}