Localization in JSF, how to remember selected locale per session instead of per request/view

46
votes

faces-config.xml:

<application>
    <locale-config>
        <default-locale>ru</default-locale>
        <supported-locale>ua</supported-locale>
    </locale-config>
</application>

In a bean action method, I'm changing the locale in the current view as follows:

FacesContext.getCurrentInstance().getViewRoot().setLocale(new Locale("ua"));

The problem is that ua Locale is applied, but only per request/view and not for session. Another request/view within the same session resets the locale back to default ru value.

How can I apply the locale for session?

5
jsfsessionjsf-2localizationinternationalization
I'm curious, how often is this technique of setting the language used? I have all my browsers in English, is this that reliable as an i18n tech? – treaz

5 Answers

88
votes

You need to store the selected locale in the session scope and set it in the viewroot in two places: once by UIViewRoot#setLocale() immediately after changing the locale (which changes the locale of the current viewroot and thus get reflected in the postback; this part is not necessary when you perform a redirect afterwards) and once in the locale attribute of the <f:view> (which sets/retains the locale in the subsequent requests/views).

Here's an example how such a LocaleBean should look like:

package com.example.faces;

import java.util.Locale;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
import javax.faces.context.FacesContext;

@ManagedBean
@SessionScoped
public class LocaleBean {

    private Locale locale;

    @PostConstruct
    public void init() {
        locale = FacesContext.getCurrentInstance().getExternalContext().getRequestLocale();
    }

    public Locale getLocale() {
        return locale;
    }

    public String getLanguage() {
        return locale.getLanguage();
    }

    public void setLanguage(String language) {
        locale = new Locale(language);
        FacesContext.getCurrentInstance().getViewRoot().setLocale(locale);
    }

}

And here's an example of the view should look like:

<!DOCTYPE html>
<html lang="#{localeBean.language}"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:h="http://java.sun.com/jsf/html">
<f:view locale="#{localeBean.locale}">
    <h:head>
        <title>JSF/Facelets i18n example</title>
    </h:head>
    <h:body>
        <h:form>
            <h:selectOneMenu value="#{localeBean.language}" onchange="submit()">
                <f:selectItem itemValue="en" itemLabel="English" />
                <f:selectItem itemValue="nl" itemLabel="Nederlands" />
                <f:selectItem itemValue="es" itemLabel="Español" />
            </h:selectOneMenu>
        </h:form>
        <p><h:outputText value="#{text['some.text']}" /></p>
    </h:body>
</f:view>
</html>

Note that <html lang> is not required for functioning of JSF, but it's mandatory how search bots interpret your page. Otherwise it would possibly be marked as duplicate content which is bad for SEO.

Related:

4
votes

I see that the problem is also with .properties file name. Java Locale us codes (lowercase) like: en_gb But automaticly created locale (by Netbeans) is lowercase_uppercase i.e.: messages_en_GB.properties Change name to: messages_en_gb.properties and it should work - if you tried everything

3
votes

This component f:view is not there your JSF page it will not work and It will shows only default english language.Provide the localae value for this f:view component then it will work fine. I faced the same problem now its working fine.

2
votes

One small remark to @BalusC great solution. If we have <f:viewAction> which executes some method in backing bean. Locale available from call to FacesContext.getCurrentInstance().getViewRoot().getLocale() inside that method would be locale that is set by user browser or default application locale, not that locale that is set on session bean by user selection(of course they can match if browser locale equals that locale that user selected).

I can stand corrected, because maybe I did something wrong when implementing solution provided by @BalusC.

EDIT. After playing with JSF lifecycle, this behavior with locale is not related to <f:viewAction>, because there is similar behavior also with @PostContruct. <f:view locale="#{localeBean.locale}"> in request(after user selected locale) is executed in render response phase. <f:viewAction> and @PostContruct methods are executed in invoke application phase. That is why logic that is executed in this method do not have access to user selected locale.

Solution that we using when we need correct locale is to inject(CDI) localeBean in other backing bean that contains <f:viewAction> and @PostContruct methods, and then set locale with UIViewRoot#setLocale() from localeBean in beginning of these methods.

0
votes

If you can use CDI and deltaspike (JSF module) in your environment, you could add the following to your LocaleBean to automatically reset the locale on the current view:

@javax.enterprise.context.SessionScoped
public class LocaleBean implements Serializable {

    ...

    public void resetLocale(@Observes @BeforePhase(JsfPhaseId.RENDER_RESPONSE) PhaseEvent event) {
        event.getFacesContext().getViewRoot().setLocale(this.locale);
    }
}