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

sergionni picture sergionni · Jan 28, 2011 · Viewed 49.7k times · Source

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?

Answer

BalusC picture BalusC · Jan 28, 2011

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.

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