Spring MVC Internationalization i18n Example | SessionLocaleResolver

Spring Framework is bundled with LocaleResolver which enables the support for Internationalization (i18n) and Localization  (L10n). In this Spring MVC Internationalization i18n Example, lets add the Internationalization support to our Spring MVC Hello World application.

We will be creating a simple Spring MVC application which displays the page contents in English, German and Italian languages.

Folder Structure:

1. Create a simple Maven webapp Project “SpringMVCInternationalization” and create a package for our source files “com.javainterviewpoint” under  src/main/java 
2. Now add the following dependency in the POM.xml

   <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
   	<modelVersion>4.0.0</modelVersion>
   	<groupId>com.javainterviewpoint</groupId>
   	<artifactId>SpringMVCInternationalization</artifactId>
   	<packaging>war</packaging>
   	<version>0.0.1-SNAPSHOT</version>
   	<name>SpringMVCInternationalization Maven Webapp</name>
   	<url>http://maven.apache.org</url>
   
   	<properties>
   		<jdk.version>1.8</jdk.version>
   		<spring.version>4.3.7.RELEASE</spring.version>
   		<jstl.version>1.2</jstl.version>
   		<servlet.version>3.1.0</servlet.version>
   		<commons.fileupload.version>1.3.2</commons.fileupload.version>
   	</properties>
   
   	<dependencies>
   		<!-- Spring Dependency -->
   		<dependency>
   			<groupId>org.springframework</groupId>
   			<artifactId>spring-webmvc</artifactId>
   			<version>${spring.version}</version>
   		</dependency>
   
   		<dependency>
   			<groupId>org.springframework</groupId>
   			<artifactId>spring-context</artifactId>
   			<version>${spring.version}</version>
   		</dependency>
   
   		<!-- JSTL Dependency -->
   		<dependency>
   			<groupId>jstl</groupId>
   			<artifactId>jstl</artifactId>
   			<version>${jstl.version}</version>
   		</dependency>
   
   		<!-- Servlet Dependency -->
   		<dependency>
   			<groupId>javax.servlet</groupId>
   			<artifactId>javax.servlet-api</artifactId>
   			<version>${servlet.version}</version>
   			<scope>provided</scope>
   		</dependency>
   	</dependencies>
   	<build>
   		<finalName>SpringMVCInternationalization</finalName>
   		<plugins>
   			<plugin>
   				<groupId>org.apache.maven.plugins</groupId>
   				<artifactId>maven-compiler-plugin</artifactId>
   				<version>3.3</version>
   				<configuration>
   					<source>${jdk.version}</source>
   					<target>${jdk.version}</target>
   				</configuration>
   			</plugin>
   		</plugins>
   	</build>
   </project>
   

3. Create the Java class HelloController.java under  com.javainterviewpoint folder.
4. Place the messages_en.properties, messages_de.properties and messages_it.properties under src/main/resources folder
5. Place the welcome.jsp under the sub directory under WEB-INF/Jsp

Spring MVC Internationalization i18n Example

Dependency Tree

[INFO] ------------------------------------------------------------------------
[INFO] Building SpringMVCInternationalization Maven Webapp 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-dependency-plugin:2.1:tree (default-cli) @ SpringMVCInternationalization ---
[INFO] com.javainterviewpoint:SpringMVCInternationalization:war:0.0.1-SNAPSHOT
[INFO] +- org.springframework:spring-webmvc:jar:4.3.7.RELEASE:compile
[INFO] |  +- org.springframework:spring-aop:jar:4.3.7.RELEASE:compile
[INFO] |  +- org.springframework:spring-beans:jar:4.3.7.RELEASE:compile
[INFO] |  +- org.springframework:spring-core:jar:4.3.7.RELEASE:compile
[INFO] |  |  \- commons-logging:commons-logging:jar:1.2:compile
[INFO] |  +- org.springframework:spring-expression:jar:4.3.7.RELEASE:compile
[INFO] |  \- org.springframework:spring-web:jar:4.3.7.RELEASE:compile
[INFO] +- org.springframework:spring-context:jar:4.3.7.RELEASE:compile
[INFO] +- jstl:jstl:jar:1.2:compile
[INFO] \- javax.servlet:javax.servlet-api:jar:3.1.0:provided
[INFO] ------------------------------------------------------------------------

Spring Configuration File –  SpringConfig-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc.xsd">

	<context:component-scan base-package="com.javainterviewpoint"> </context:component-scan>
	<mvc:annotation-driven> </mvc:annotation-driven>

	<bean id="messageSource"
		class="org.springframework.context.support.ResourceBundleMessageSource">
		<property name="basename" value="messages" />
	</bean>
	
	<bean id="localeResolver"
		class="org.springframework.web.servlet.i18n.SessionLocaleResolver">
		<property name="defaultLocale" value="en" />
	</bean>

	<mvc:interceptors>
		<bean class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor">
			<property name="paramName" value="lang" />
		</bean>
	</mvc:interceptors>

	<bean id="viewResolver"
		class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<property name="prefix">
			<value>/WEB-INF/Jsp/</value>
		</property>
		<property name="suffix">
			<value>.jsp</value>
		</property>
	</bean>

</beans>

• <context:component-scan> will let the Spring Container to search for all the annotation under the package “com.javainteriviewpoint”. 
• <mvc:annotation-driven/> annotation will activate the @Controller, @RequestMapping, @Valid etc annotations.
• ResourceBundleMessageSource is one of the Spring Message source entity which implements the MessageSource interface, it will be used to read the “message_*.properties” files present in the classpath. We will be passing the name of the property file to the “basename” property.

<bean id="messageSource"
  class="org.springframework.context.support.ResourceBundleMessageSource">
	<property name="basename" value="messages" />
</bean>

• We can get the Current locale of the user by different locale resolution strategy such as Accept-Language which is present in the header, session, cookie. All the resolvers provided by Spring will be implementing the LocaleResolver.
• We have used SessionLocaleResolver in our case to use the locale for the particular session and we have set the defaultLocale to English.

<bean id="localeResolver"
  class="org.springframework.web.servlet.i18n.SessionLocaleResolver">
	<property name="defaultLocale" value="en" />
</bean>

• Note: The bean id has to be “localeResolver”,  if not Spring will try to register the default resolver AcceptHeaderLocaleResolver
• LocaleChangeInterceptor is a special interceptor in Spring which enables you to change the locale based on the parameter which is present in the request. In our case it is “lang”, using which the user can change the change a different language.

<mvc:interceptors>
  <bean class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor">
     <property name="paramName" value="lang" />
  </bean>
</mvc:interceptors>

• The view is resolved through “InternalResourceViewResolver” which searches for the jsp files under the /WEB-INF/Jsp/ directory.

<bean id="viewResolver"
  class="org.springframework.web.servlet.view.InternalResourceViewResolver">
	<property name="prefix">
		<value>/WEB-INF/Jsp/</value>
	</property>
	<property name="suffix">
		<value>.jsp</value>
	</property>
</bean>

locale specific message resources

Our application supports 3 languages English, German and Italian. Add the messages in each languges to the corresponding property file.

messages_en.properties

spring.welcome = Welcome to Javainterviewpoint
spring.content = Spring MVC Internationalization (i18n) and Localization (L10n) Example

messages_de.properties

spring.welcome = Willkommen bei Javainterviewpoint
spring.content = Spring MVC Internationalisierung (i18n) und Lokalisierung (L10n) Beispiel

messages_it.properties

spring.welcome = Benvenuti in Javainterviewpoint
spring.content =  Esempio di Spring MVC Internationalization (i18n) e Localization (L10n)

web.xml

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
    version="3.1">

    <servlet>
        <servlet-name>SpringConfig</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
         <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value></param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>SpringConfig</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
    
     <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/SpringConfig-servlet.xml</param-value>
    </context-param>
	
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
</web-app>

The web.xml has everything about the application that a server needs to know, which is placed under the WEB-INF directory.  It contains the name of the SpringConfiguration file, when the DispatcherServlet is initialized the framework will try to load a configuration file “[servlet-name]-servlet.xml” under the WEB-INF directory.

HelloController.java

package com.javainterviewpoint;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class HelloController
{
    @GetMapping("/hello")
    public ModelAndView welcome()
    {
        return new ModelAndView("welcome");
    }
}

• We have annotated our “HelloController” class with @Controller annotation which tells Spring Container to treat this class as a Controller.
• @GetMapping annotation on top of welcome() redirects the request to this method, when the request given is “/hello” and it can take only GET request and redirects the user to the welcome.jsp

welcome.jsp

The welcome.jsp should be created under /WEB-INF/Jsp folder.

<%@ page contentType="text/html;charset=UTF-8"%>
<%@ taglib prefix="spring" uri="http://www.springframework.org/tags"%>
<html>
<body>
	<h1>Spring MVC Internationalization i18n Example</h1>

	Select Language : <a href="?lang=en">English</a> | <a href="?lang=de">German</a> | <a href="?lang=it">Italian</a>

	<h2>
		<spring:message code="spring.welcome" />
	</h2>
	<h3>
		<spring:message code="spring.content" />
	</h3>

</body>
</html>

The <spring:message> tag provides the internationalization support, the code attribute act as a key while looking up for the messages in the property file.

Output

Hit on the URL : http://localhost:8080/SpringMVCInternationalization/hello

Since we have provided the defaultLocale as English the page will load its content in English

Hit on the URL http://localhost:8080/SpringMVCInternationalization/hello?lang=de , alternatively click on the German Hyperlink to make the page load it contents in German

Hit on the URL http://localhost:8080/SpringMVCInternationalization/hello?lang=it to load the contents in italian