Introduction
This is a simple demonstration of localization implemented in a JSF application. Localization is the process of adapting an application to the language, culture and formats of a particular region known as locale. In this article I cover localizing text, date and currency.
Background
The Locale class from the java.util package is used to specify a geographical location to be used to implement Localization. The Locale class has the following constructors:
Locale(String language)Locale(String language, String country)Locale(String language,String country,String variant)
For example, you can use the following code to specify the french language as spoken in France.
Locale locale=new Locale("fr","FR");
The ResourceBundle class from the java.util package is used to load resource bundle files. A resource bundle is a Java .properties file which contains locale specific strings. It consists of Key-Value pairs for each property. The resource bundle file is named as BaseFileName_LanguageCode_CountryCode.properties. For example, the resource bundle file for French language as spoken in France will be MessageBundle_fr_FR.properties.
The following code shows how we can use the ResourceBundle class to load the resource bundle for French language:
ResourceBundle bundle=ResourceBundle.getBundle("MessageBundle",locale);
The corresponding MessageBundle_fr_FR.properties file contains the following code:
# To change this license header, choose License Headers in Project Properties.
# To change this template file, choose Tools | Templates
# and open the template in the editor.
message=Bonjour
language=French
imageUrl=france.png
The DateFormat class from the java.text package is used to localize dates. The following is an example of how to localize the current date:
DateFormat df=DateFormat.getDateInstance(DateFormat.SHORT, locale);
currDate=df.format(new Date());
The NumberFormat class from the java.text package is used to localize numbers. The following is an example of how to localize an amount as currency:
NumberFormat nf=NumberFormat.getCurrencyInstance(locale);
amount=nf.format(12345.67);
Using the code
Since this article is based on JSF, I have created a Resource Scoped Managed Bean class called HelloBean to perform the actual localization and return localized data to the JSF page. The Managed Bean consists of the following properties:
private String language;
private String message;
private String currDate;
private String amount;
private String imageUrl;
It consists of getter methods for the above properties and methods to localize these properties in different languages and countries. The following code shows localization in English and French languages:
public void showEnglishMessage()
{
Locale locale=new Locale("en","US");
ResourceBundle bundle=ResourceBundle.getBundle("MessageBundle",locale);
localize(bundle, locale);
}
public void showFrenchMessage()
{
Locale locale=new Locale("fr","FR");
ResourceBundle bundle=ResourceBundle.getBundle("MessageBundle",locale);
localize(bundle, locale);
}
public void localize(ResourceBundle bundle,Locale locale)
{
message=bundle.getString("message");
language=bundle.getString("language");
imageUrl=bundle.getString("imageUrl");
DateFormat df=DateFormat.getDateInstance(DateFormat.SHORT, locale);
currDate=df.format(new Date());
NumberFormat nf=NumberFormat.getCurrencyInstance(locale);
amount=nf.format(12345.67);
}
In the above code, showEnglishMessage() and showFrenchMessage() user defined methods call another user defined method called localize() which performs localization using the Locale and ResourceBundle parameters.
Following are the English and French language resource bundle files:
# To change this license header, choose License Headers in Project Properties.
# To change this template file, choose Tools | Templates
# and open the template in the editor.
message=Hello
language=English
imageUrl=us.png
# To change this license header, choose License Headers in Project Properties.
# To change this template file, choose Tools | Templates
# and open the template in the editor.
message=Bonjour
language=French
imageUrl=france.png
The properties of the Managed Bean are bound to JSF controls on the index.xhtml JSF page as follows:
='1.0'='UTF-8'
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://xmlns.jcp.org/jsf/html">
<h:head>
<title>Localization Demo</title>
</h:head>
<h:body>
<h:form>
<div align="center">
<h1>Localization Demo</h1>
<h:panelGrid columns="2" border="5">
<h:outputLabel for="txtLanguage" value="Language: "/>
<h:outputText id="txtLanguage" value="#{helloBean.language}"/>
<h:outputLabel for="txtMessage" value="Message: "/>
<h:outputText id="txtMessage" value="#{helloBean.message}"/>
<h:outputLabel for="txtDate" value="Date: "/>
<h:outputText id="txtDate" value="#{helloBean.currDate}"/>
<h:outputLabel for="txtAmount" value="Amount(Currency): "/>
<h:outputText id="txtAmount" value="#{helloBean.amount}"/>
<h:outputLabel for="imgFlag" value="Flag: "/>
<h:graphicImage id="imgFlag" url="#{helloBean.imageUrl}"
width="100" height="100" />
<h:commandButton id="cmdEnglish" value="English Hello"
action="#{helloBean.showEnglishMessage}"
style="width: 170px" />
<h:commandButton id="cmdFrench" value="French Hello"
action="#{helloBean.showFrenchMessage}"
style="width: 170px" />
<h:commandButton id="cmdGerman" value="German Hello"
action="#{helloBean.showGermanMessage()}"
style="width: 170px" />
<h:commandButton id="cmdSpanish" value="Spanish Hello"
action="#{helloBean.showSpanishMessage()}"
style="width: 170px" />
<h:commandButton id="cmdItalian" value="Italian Hello"
action="#{helloBean.showItalianMessage()}"
style="width: 170px" />
<h:commandButton id="cmdTurkish" value="Turkish Hello"
action="#{helloBean.showTurkishMessage()}"
style="width: 170px" />
</h:panelGrid>
</div>
</h:form>
</h:body>
</html>
Points of Interest
As this article demonstrates, Java provides a very easy way to localize data. The same approach can be used in any kind of Java environment.
The flag images used in this article were downloaded from the following site:
https://www.countryflags.com/en/
