Configuration in struts 2.0 application:

When ever we are developing struts based application we have to do some configuration code changes. It includes the following:

1) web.xml- we have to specify the controler which will handle each request and determine the action to process the request.

Code Sample:

  <filter>
      <filter-name>struts2</filter-name>
      <filter-class>
         org.apache.struts2.dispatcher.FilterDispatcher
      </filter-class>
      <init-param>
         <param-name>struts.devMode</param-name>
         <param-value>true</param-valu>>
      </init-param>
   </filter>

   <filter-mapping>
      <filter-name>struts2</filter-name>
      <url-pattern>/*</url-pattern>
   </filter-mapping>

2) struts.xml and struts.properties- Most of the time we do not use struts.properties, it is used to override the default properties.

In struts.xml we specify a lot of things like package, action, interceptors, results, global-exception esult, constant properties etc.

Example:

<struts>
<!-- Package: We can have multiple packages with 
                             different namespace -->
   <package name="ankit" namespace="/" 
                          extends="struts-default">
 <!-- Global Result-->
 <global-results>
        <result name="exception">jsp/error.jsp</result>
    </global-results>
<!-- Global Exception Mapping-->
    <global-exception-mappings>
        <exception-mapping exception="java.lang.Exception"
            result="exception" />
    </global-exception-mappings>
   
   <!-- Action -->
   <action name="examp" 
         class="com.ankit.struts2.ExampAction"
         method="execute">
<!-- Interceptor -->         
		 <interceptor-ref name="params"/>
<!-- Result -->         
		 <result name="success">/Output.jsp</result>
      </action>
	</package>
</struts>

We can have multiple file for configuration, so that we can easily maintain the code in seperate packages:

In main struts.xml we can have below entry:

<package name="def" namespace="/" extends="struts-default">  
</package>  
  
<include file="a/struts-a.xml"></include>  
<include file="a/struts-b.xml"></include>

Here struts-1.xml can have specification for a functionality and struts-b.xml will have specification for b functionality.