Multiple DispatcherServlet mapping for servlets in Spring SVC

If you know Spring, you know what place DispatcherServlet holds in this framework as it is the one for handling View mapping in Spring MVC and the files. I recently had my play with this framework along-with couple of others and there I faced a problem in Spring MVC when I was done with multiple sections in a specific project. I wanted to define mapping for different sections separately so that if I access any file using http://localhost:8080/module1/index.html, I should be getting completely different section mapped in module1-servlet.xml which is defined in web deployer web.xml as –

<servlet>
        <servlet-name>module1</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    </servlet> 

<servlet-mapping>
    <servlet-name>module1</servlet-name>
    <url-pattern>*.html</url-pattern>
</servlet-mapping> 

 

Bean declaration in module1-servlet.xml is like –

    <bean name="/module1/index.html" class="org.springframework.showcase.module1.web.IndexController">
        <property name="viewName" value="module1/index"/>
    </bean>

 

 

And then I try to create DispatcherServlet for another section  – module2, with same signature as for module1 in web.xml

<servlet>
        <servlet-name>module2</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    </servlet> 

<servlet-mapping>
    <servlet-name>module2</servlet-name>
    <url-pattern>*.html</url-pattern>
</servlet-mapping> 

With this mapping, I create another servlet named  module2-servlet.xml and there bean declaration looks like –

    <bean name="/module2/index.html" class="org.springframework.showcase.module1.web.IndexController">
        <property name="viewName" value="module2/index"/>
    </bean>

 

With this configuration, when I try to open http://localhost:8080/module2/index.html, 404 error is displayed which means Page Not Found. If you have worked on Struts framework, you might already be knowing the work-around.

 

This is because we are using same <url-pattern> tag for both modules with same servlet class – DispatcherServlet which is not correct.  We can have multiple DispatcherServlets with distinct <url-pattern> tag values. So in order to sort out this issue, I changed module2 entry in web.xml as –  

<servlet>
        <servlet-name>module2</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    </servlet> 

<servlet-mapping>
    <servlet-name>module2</servlet-name>
    <url-pattern>*.htm</url-pattern>
</servlet-mapping> 

And bean entry in module2-servlet.xml was changed to –

    <bean name="/module2/index.htm" class="org.springframework.showcase.module1.web.IndexController">
        <property name="viewName" value="module2/index"/>
    </bean>

 

After this, I was able to open http://localhost:8080/module2/index.htm

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