Spring Beans on Web Application Scope

There are times when we’d like to place injected Spring beans onto a scope where they can be accessed directly by JSTL EL expressions (${variable}). Perhaps URLs from JEE Resource References to be used in hrefs.

Spring has a class that enables us to do this directly from its configuration file, ServletContextAttributeExporter. This class will place beans on “Web Application Scope”, also known as “Servlet Context”.

It has attribute of a Map of keys to value objects, into which you can inject any Spring-defined beans you want, under any key names.

For instance, with a URL resource reference:

    <!-- JEE URL resource-reference -->  
    <jee:jndi-lookup id="staticContentUrl" jndi-name="staticContentUrl" resource-ref="true"/>

    <!-- Add specified beans directly to Web Application Scope (a.k.a. Servlet Context)  
         for global access, particularly in JSPs -->  
    <bean class="org.springframework.web.context.support.ServletContextAttributeExporter">  
        <property name="attributes">  
            <map>  
                <entry key="staticContent" value-ref="staticContentUrl"/>  
            </map>  
        </property>  
    </bean>

Then you would reference these values in a JSP like this:

<a href="${staticContent}/index.html"/>Home Page</a>