DelegetingActionProxy

DelegetingActionProxy solves the problem of having to create an action as subclasses of ActionSupport. It is better to define beans in the Spring application context are proxies to the Struts Actions.

For example, class SpringIndexAction extends Action and declares a setter for the productionManager property. We add an action declaration to the Struts configuration file struts-config.xml.

[action path="/sindex"
type="org.springframework.web.struts.DelegatingActionProxy"
validate="false"]
[forward name="success"
path=".index"/]
[/action]

Notice the action type is set to DelegatingActionProxy, which is a Spring class that delegates all calls to the real bean of the SpringIndexAction class.

Before we can use DelegatingActionProxy, we first need to add the ContextLoaderPlugin bean to the Struts configuration file.

[plug-in
className="org.springframework.web.struts.ContextLoaderPlugin"]
[set-property property="contextConfigLocation"
value="/WEB-INF/actionContext.xml"/]
[/plug-in]

We declare the SpringIndexAction in the actionContext.xml file.

[beans]
[bean name="/sindex" class="com.....actions.SpringIndexAction"]
[property name="productManager"][ref
bean="productManager"/][/property]
[/bean]
[/beans]

When we now make a request to the /sindex.do URL, DelegatingActionProxy looks up the bean with its name set to /sindex. It uses the beans defined in the WebApplicationContext that is loaded by the ContextLoaderPlugin declared in the file specified in its contextConfiguration property. The /sindex bean is the actual SpringIndexAction, it is instantiated, and its productManager property is set.

The difference after using DelegetingActionProxy is that the SpringIndexAction is a fully Spring-managed bean and we have no manual dependency lookup code in the Action.