Struts – MappingDispatchAction Example

Struts MappingDispatchAction class is used to group similar functionality into a single action class, and execute the function depends on parameter attribute of the corresponding ActionMapping. Here’s an example to show the use of MappingDispatchAction.

Download this example – Struts-MappingDispatchAction-Example.zip

1. MappingDispatchAction class

Extends the MappingDispatchAction class, and declares two methods – generateXML() and generateExcel().

MyCustomDispatchAction.java

package com.mkyong.common.action;
 
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.actions.MappingDispatchAction;
 
public class MyCustomDispatchAction extends MappingDispatchAction{
 
	public ActionForward generateXML(ActionMapping mapping,ActionForm form,
		HttpServletRequest request,HttpServletResponse response) 
        throws Exception {
 
		request.setAttribute("method", "generateXML is called");
 
	        return mapping.findForward("success");
	}
 
	public ActionForward generateExcel(ActionMapping mapping,ActionForm form,
		HttpServletRequest request,HttpServletResponse response) 
	throws Exception {
 
		request.setAttribute("method", "generateExcel is called");
 
		return mapping.findForward("success");
	}
}

2. Struts configuration

Declares two action mappings, each point to same MyCustomDispatchAction class with different parameter attributes.

struts-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts-config PUBLIC 
"-//Apache Software Foundation//DTD Struts Configuration 1.3//EN" 
"http://jakarta.apache.org/struts/dtds/struts-config_1_3.dtd">
 
<struts-config>
 
	<action-mappings>
 
	 	<action
			path="/CustomDispatchActionXML"
			type="com.mkyong.common.action.MyCustomDispatchAction"
			parameter="generateXML"
			>
 
			<forward name="success" path="/pages/DispatchExample.jsp"/>
 
		</action>
 
		<action
			path="/CustomDispatchActionExcel"
			type="com.mkyong.common.action.MyCustomDispatchAction"
			parameter="generateExcel"
			>
 
			<forward name="success" path="/pages/DispatchExample.jsp"/>
 
		</action>
 
 
		<action
			path="/Test"
			type="org.apache.struts.actions.ForwardAction"
			parameter="/pages/TestForm.jsp"
			>
		</action>
 
	</action-mappings>
 
</struts-config>

3. View page

In JSP page, the links work as following :

1. /CustomDispatchActionXML will execute the generateXML() method.
2. /CustomDispatchActionExcel will execute the generateExcel() method.

TestForm.jsp

<%@taglib uri="http://struts.apache.org/tags-html" prefix="html"%>
<html>
<head>
</head>
<body>
 
<h2>Struts - DispatchAction Example</h2>
 
<h4>html:link</h4>
<p>
   <html:link action="/CustomDispatchActionXML" >
           Generate XML File
   </html:link>
   |
   <html:link action="/CustomDispatchActionExcel" >
           Generate Excel File
   </html:link>
</p> 
 
<h4>a href</h4>
<p>
   <a href="CustomDispatchActionXML.do">
           Generate XML File
   </a>
   |
   <a href="CustomDispatchActionExcel.do" >
           Generate Excel File
   </a>
</p> 
 
</body>
</html>

DispatchExample.jsp

<%@taglib uri="http://struts.apache.org/tags-bean" prefix="bean"%>
<%@taglib uri="http://struts.apache.org/tags-logic" prefix="logic"%>
<html>
<head>
</head>
<body>
 
<h2>Struts - DispatchAction Example</h2>
 
<bean:write name="method"/>
 
</body>
</html>