Understanding Struts Controller
In this section I will describe you the Controller part of the Struts Framework. I will
show you how to configure the struts-config.xml file to map the request to some
destination servlet or jsp file.
The class org.apache.struts.action.ActionServlet is the heart of the Struts
Framework. It is the Controller part of the Struts Framework. ActionServlet is
configured as Servlet in the web.xml file as shown in the following code snippets.
<!-- Standard Action Servlet Configuration (with debugging) -->
<servlet>
<servlet-name>action</servlet-name>
<servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
<init-param>
<param-name>config</param-name>
<param-value>/WEB-INF/struts-config.xml</param-value>
</init-param>
<init-param>
<param-name>debug</param-name>
<param-value>2</param-value>
</init-param>
<init-param>
<param-name>detail</param-name>
<param-value>2</param-value>
</init-param>
<load-on-startup>2</load-on-startup>
</servlet>
This servlet is responsible for handing all the request for the Struts Framework, user
can map the specific pattern of request to the ActionServlet. <servlet-mapping> tag
in the web.xml file specifies the url pattern to be handled by the servlet. By default
it is *.do, but it can be changed to anything. Following code form the web.xml file
shows the mapping.
<!-- Standard Action Servlet Mapping -->
<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
The above mapping maps all the requests ending with .do to the ActionServlet.
ActionServlet uses the configuration defined in struts-config.xml file to decide the
destination of the request. Action Mapping Definitions (described below) is used to
map any action. For this lesson we will create Welcome.jsp file and map the
"Welcome.do" request to this page.
docsity.com
