JavaServer Pages, 3rd Edition

The Locale Class

All Java classes that provide localization support use a class named java.util.Locale. An instance of this class represents a particular geographical, political, or cultural region, as specified by a combination of a language code and a country code. Java classes that perform tasks that differ depending on a user’s language and local customs—so called locale-sensitive operations—use a Locale instance to decide how to operate. Examples of locale-sensitive operations are interpreting date strings and formatting numeric values.

You create a Locale instance using a constructor that takes the country code and language code as arguments:

java.util.Locale usLocale = new Locale("en", "US");

Here, a Locale for U.S. English is created. George Bernard Shaw (a famous Irish playwright) once observed that “England and America are two countries divided by a common language,” so it’s no surprise that both a language code and a country code are needed to describe some locales completely. The language code, a lowercase two-letter combination, is defined by the ISO 639 standard available at http://www.ics.uci.edu/pub/ietf/http/related/iso639.txt. The country code, an uppercase two-letter combination, is defined by the ISO 3166 standard, available at http://www.chemie.fu-berlin.de/diverse/doc/ISO_3166.html. Tables Table 14-1 and Table 14-2 show some of these codes.

Table 14-1. ISO-639 language codes

Language code	Language
af	Afrikaans
da	Danish
de	German
el	Greek
en	English ...