Locale Sensitive Operations

<< Locales, Localization Methods and Resource Bundles

<< JDK (Java Development Kit) Tutorials

This section provides a tutorial example on how to convert date objects to strings in different locales using java.util.SimpleDateFormat class.

Locale Sensitive Operations: Operations that require to know a user's locale in order to tailor information for the user. For example, formatting a calendar date into a string is a locale sensitive operation, because for an English speaking user in US, a calendar date should be formatted as "Mon Oct 21 20:54:05 EDT 2002"; but for a French speaking user, the same date should be formatted as "lun. oct. 21 20:54:05 EDT 2002".

Separated formatter classes are provided to handle locale sensitive operations related to some predefined classes. Here is a list of formatter classes:

Formatter          Data	               Operations
Class              Class

SimpleDateFormat   GregorianCalendar   Formating and parsing
DecimalFormat      Number              Formating and parsing

The following program shows how to internationalize the formatting operation of dates, numbers and currencies:

/**
 * FormatLocaleTest.java
 * Copyright (c) 2002 by Dr. Herong Yang
 */
import java.util.*;
import java.text.*;
class FormatLocaleTest {
   public static void main(String[] a) {
      showDateFormat();
      showNumberFormat();
   }
   public static void showDateFormat() {
      Date now = new Date(); // the current time
      DateFormat df;
      SimpleDateFormat sdf;
      System.out.println("Default date format:");
      df = DateFormat.getDateTimeInstance(DateFormat.LONG,
         DateFormat.LONG);
      System.out.println("   Locale(Default): " + df.format(now));
      df = DateFormat.getDateTimeInstance(DateFormat.LONG,
         DateFormat.LONG, Locale.FRANCE);
      System.out.println("   Locale(France): " + df.format(now));
      df = DateFormat.getDateTimeInstance(DateFormat.LONG,
         DateFormat.LONG, Locale.FRENCH);
      System.out.println("   Locale(French): " + df.format(now));
      df = DateFormat.getDateTimeInstance(DateFormat.LONG,
         DateFormat.LONG, Locale.GERMAN);
      System.out.println("   Locale(German): " + df.format(now));
      System.out.println("Customized date format:");
      sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy");
      System.out.println("   Locale(Default): " + sdf.format(now));
      sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy", 
         Locale.FRENCH);
      System.out.println("   Locale(French): " + sdf.format(now));
      sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy", 
         Locale.GERMAN);
      System.out.println("   Locale(German): " + sdf.format(now));
      sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy", 
         Locale.CHINESE);
      System.out.println("   Locale(Chinese): " + sdf.format(now));
   }
   public static void showNumberFormat() {
      double num = -1234.5678;
      NumberFormat nf;
      System.out.println("Number format:");
      nf = NumberFormat.getNumberInstance();
      System.out.println("   Locale(Default): "+ nf.format(num));
      nf = NumberFormat.getNumberInstance(Locale.FRANCE);
      System.out.println("   Locale(France): "+ nf.format(num));
      nf = NumberFormat.getNumberInstance(Locale.FRENCH);
      System.out.println("   Locale(French): "+ nf.format(num));
      nf = NumberFormat.getNumberInstance(Locale.JAPAN);
      System.out.println("   Locale(Japanese): "+ nf.format(num));

      System.out.println("Currency format:");
      nf = NumberFormat.getCurrencyInstance();
      System.out.println("   Locale(Default): "+ nf.format(num));
      nf = NumberFormat.getCurrencyInstance(Locale.FRANCE);
      System.out.println("   Locale(France): "+ nf.format(num));
      nf = NumberFormat.getCurrencyInstance(Locale.FRENCH);
      System.out.println("   Locale(French): "+ nf.format(num));
      nf = NumberFormat.getCurrencyInstance(Locale.JAPAN);
      System.out.println("   Locale(Japanese): "+ nf.format(num));
   }
}

Output:

Default date format:
   Locale(Default): November 1, 2002 9:45:44 AM EST
   Locale(France): 1 novembre 2002 09:45:44 EST
   Locale(French): 1 novembre 2002 09:45:44 EST
   Locale(German): 1. November 2002 09:45:44 EST
Customized date format:
   Locale(Default): Fri Nov 01 09:45:44 EST 2002
   Locale(French): ven. nov. 01 09:45:44 EST 2002
   Locale(German): Fr Nov 01 09:45:44 EST 2002
   Locale(Chinese): ??? ??? 01 09:45:44 EST 2002
Number format:
   Locale(Default): -1,234.568
   Locale(France): -1á234,568
   Locale(French): -1á234,568
   Locale(Japanese): -1,234.568
Currency format:
   Locale(Default): ($1,234.57)
   Locale(France): -1á234,57 F
   Locale(French): -1á234,57 ñ
   Locale(Japanese): -?1,235

Note that:

• When the locale is changed, the default formatter not only changes the language, but also changes the pattern.
• The "?" in the output of Chinese locale is caused by the console window not able to display the Chinese characters.
• The currency formatter is sensitive to not only the language, but also to the country.
• The precision is also adjusted in the default currency formatter for Japanese.

Sections in This Chapter

java.util.Locale - Localization and Internationalization

Locale Sensitive Operations

java.util.ResourceBundle - Resource Bundle Abstract Class

java.util.ListResourceBundle - Resource Bundles as Lists

java.util.PropertyResourceBundle - Resource Bundles as Properties Files

java.util.ResourceBundle.getBundle() - Retrieving Resource Bundles