Struts 2 mapping interceptors to action

Struts 2 developers are used to declare the actions belong to a package that extend the “struts-default“, which contains the default set of interceptors.

<package name="default" namespace="/" extends="struts-default">
	<action name="testingAction" 
		class="com.mkyong.common.action.TestingAction" >
		<result name="success">pages/result.jsp</result>
	</action>
</package>

The default set of interceptors are grouped as “defaultStack” in struts-default.xml file, which is located in the struts2-core.jar file. The “defaultStack” provides all the core Struts 2 functionality, which is suit the need of most application.

Try study the struts-default.xml file, it’s always the best interceptors reference.

Mapping interceptor to action

To map other interceptors to action, use the “interceptor-ref” element.

<package name="default" namespace="/" extends="struts-default">
	<action name="testingAction" 
		class="com.mkyong.common.action.TestingAction" >
		<interceptor-ref name="timer"/>
		<interceptor-ref name="logger"/>
		<result name="success">pages/result.jsp</result>
	</action>
</package>

In above snippet code, it map the “timer” and “logger” interceptors to the “TestingAction” action class via “interceptor-ref” element.

The interceptors will fire in the order they’re declared.

Since the “TestingAction” is declared it’s own interceptors, it’s immediate loses all the inherit default set of interceptors, you must explicitly declare the “defaultStack” in order to use it, see below example.

<package name="default" namespace="/" extends="struts-default">
	<action name="testingAction" 
		class="com.mkyong.common.action.TestingAction" >
		<interceptor-ref name="timer"/>
		<interceptor-ref name="logger"/>
		<interceptor-ref name="defaultStack"/>
		<result name="success">pages/result.jsp</result>
	</action>
</package>