Spring 3 MVC: Internationalization & Localization Tutorial with Example

Ref:- http://viralpatel.net/blogs/spring-3-mvc-internationalization-i18n-localization-tutorial-example/

What is i18n and L10n?

In computing, internationalization and localization are means of adapting computer software to different languages and regional differences. Internationalization is the process of designing a software application so that it can be adapted to various languages and regions without engineering changes. Localization is the process of adapting internationalized software for a specific region or language by adding locale-specific components and translating text.
The terms are frequently abbreviated to the numeronyms i18n (where 18 stands for the number of letters between the first i and last n in internationalization) and L10n respectively, due to the length of the words. The capital L in L10n helps to distinguish it from the lowercase i in i18n.

Our Goal

Our goal is to add Internationalization and Localization support to our Spring MVC application. Once finished our app will look like.

We will add two languages support to our application: English and German. Depending on the locale setting of users browser, the appropriate language will be selected. Also user will be able to select the language from top-right corner of the application.

Message Resouces File

We will create two properties file which will contain all the messages to be displayed in the application. These files are kept in a source folder called “resources”. Create a source folder in your project by Right click on Project name > New > Source Folder and name it resources.

Create two files messages_en.properties and messages_de.properties in this folder and copy following content into it.

File: resources/messages_en.properties

label.firstname=First Name label.lastname=Last Name label.email=Email label.telephone=Telephone label.addcontact=Add Contact   label.menu=Menu label.title=Contact Manager     label.footer=© test

File: resources/messages_de.properties

label.firstname=Vorname label.lastname=Familiename label.email=Email label.telephone=Telefon label.addcontact=Addieren Kontakt   label.title=Kontakt Manager label.menu=Menü     label.footer=© test

Configuring Internationalization (i18n) / Localization (L10n) in Spring MVC

Now we have created message resource properties for our application. We need to declare these files in spring configuration file. We will use class org.springframework.context.support.ReloadableResourceBundleMessageSource to define the message resources.
Also, note that we will provide a feature where user will be able to select language for the application. This is implemented by using org.springframework.web.servlet.i18n.LocaleChangeInterceptor class. The LocaleChangeInterceptor class will intercept any changes in the locale. These changes are then saved in cookies for future request. org.springframework.web.servlet.i18n.CookieLocaleResolver class will be used to store the locale changes in cookies.

Add following code in the spring-servlet.xml file.

File:WebContent/WEB-INF/spring-servlet.xml

<bean id="messageSource"     class="org.springframework.context.support.ReloadableResourceBundleMessageSource">     <property name="basename" value="classpath:messages" />     <property name="defaultEncoding" value="UTF-8"/> </bean>   <bean id="localeChangeInterceptor"     class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor">     <property name="paramName" value="lang" /> </bean>   <bean id="localeResolver"     class="org.springframework.web.servlet.i18n.CookieLocaleResolver">     <property name="defaultLocale" value="en"/> </bean>   <bean id="handlerMapping"     class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping">     <property name="interceptors">         <ref bean="localeChangeInterceptor" />     </property> </bean>

Note that in above configuration we have defined basename property in messageSource bean to classpath:messages. By this, spring will identify that the message resource message_ will be used in this application.

Change the View – The JSPs

Now as we have created two message resources files and configured it in Spring MVC, we will use these messages in the JSP files. Open all the JSP files of our demo application and update with following code.

File:WebContent/WEB-INF/jsp/header.jsp

<%@taglib uri="http://www.springframework.org/tags" prefix="spring"%>   <h3><spring:message code="label.title"/></h3>   <span style="float: right">     <a href="?lang=en">en</a>     |     <a href="?lang=de">de</a> </span>

File:WebContent/WEB-INF/jsp/menu.jsp

<%@taglib uri="http://www.springframework.org/tags" prefix="spring"%>   <p><spring:message code="label.menu"/></p>

File:WebContent/WEB-INF/jsp/footer.jsp

<%@taglib uri="http://www.springframework.org/tags" prefix="spring"%>   <spring:message code="label.footer"/>

File:WebContent/WEB-INF/jsp/contact.jsp

<%@taglib uri="http://www.springframework.org/tags" prefix="spring"%> <%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%> <html> <head>     <title>Spring 3 MVC Series - Contact Manager</title> </head> <body>       <form:form method="post" action="addContact.html">       <table>     <tr>         <td><form:label path="firstname"><spring:message code="label.firstname"/></form:label></td>         <td><form:input path="firstname" /></td>     </tr>     <tr>         <td><form:label path="lastname"><spring:message code="label.lastname"/></form:label></td>         <td><form:input path="lastname" /></td>     </tr>     <tr>         <td><form:label path="lastname"><spring:message code="label.email"/></form:label></td>         <td><form:input path="email" /></td>     </tr>     <tr>         <td><form:label path="lastname"><spring:message code="label.telephone"/></form:label></td>         <td><form:input path="telephone" /></td>     </tr>     <tr>         <td colspan="2">             <input type="submit" value="<spring:message code="label.addcontact"/>"/>         </td>     </tr> </table>        </form:form> </body> </html>

Note that in above JSP, we used <spring:message> tag to display the message from resource bundle.
One thing that we must note here is that in header.jsp file, we have specified two links to select language. The link sets a request parameter ?lang= when user click on this link. Note that spring identifies this request parameter by using LocaleChangeInterceptor interceptor and change the local accordingly. Also note that while configuring LocaleChangeInterceptor in spring-servlet.xml file, we have specified property “paramName” with value “lang”

<property name="paramName" value="lang" />

Thus the Spring framework will look for a parameter called “lang” from request.

That’s All Folks

That’s pretty much it :) We just added Internationalization and Localization support to our demo Spring 3.0 MVC application. All you have to do is just execute the app in Eclipse. Press Alt + Shift + X, R.