The Java EE 5 Tutorial

Establishing the Locale

To get the correct strings for a given user, a web application either retrieves the locale (set by a browser language preference) from the request using the getLocale method, or allows the user to explicitly select the locale.

The JSTL versions of Duke’s Bookstore automatically retrieve the locale from the request and store it in a localization context (see Internationalization Tag Library). It is also possible for a component to explicitly set the locale by using the fmt:setLocale tag.

The JavaServer Faces version of Duke’s Bookstore allows the user to explicitly select the locale. The user selection triggers a method that stores the locale in the FacesContext object. The locale is then used in resource bundle selection and is available for localizing dynamic data and messages (see Localizing Dynamic Data):

<h:commandLink id="NAmerica" action="storeFront"
    actionListener="#{localeBean.chooseLocaleFromLink}">
    <h:outputText value="#{bundle.english}" />
</h:commandLink>
public void chooseLocaleFromLink(ActionEvent event) {
    String current = event.getComponent().getId();
    FacesContext context = FacesContext.getCurrentInstance();
    context.getViewRoot().setLocale((Locale)
        locales.get(current));
}