Interceptors

Interceptors are just like filters in servlets. As you observe the below figure, a request is processed through the interceptor, before it handled by action object.

How to declare interceptors

<interceptors>

            <interceptor name="validation" class="ValidateData"/>

            <interceptor name="logger" class="LogData"/>

</interceptors>

You can declare interceptors inside a package like above.

How to apply interceptor to action

 <action name="numberCheck" class="NumberCheckAction">

            <interceptor-ref name="validation" />

            <result name="success">/success.jsp</result>

            <result name="failure">/failure.jsp</result>

</action>

Use <interceptor-ref> element to apply an interceptor to an action. In the above case interceptor ‘validation’ is applied to the action named ‘numberCheck’.

As you observe the above figure, whenever client submits a request, it passes through interceptors before action class handles it. In the same way, result also passed back to the client, through interceptors in reverse order.

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