DispatchAction Functionality in Struts 2

✔ STRUTS 2 CHAPTERS:-

1. Struts2 Overview
2. Struts2 Architecture
3. Struts2 Configuration Files
4. Action in Struts2
5. Action in Struts2 by using Pojo Class
6. Action in struts2 by Implementing Action Interface
7. Action in Struts2 by Extending Action Support Class
8. Struts2 Hello World Example
9. Multiple Configuration File in Struts2
10. OGNL in Struts2
11. Value Stack in Struts2
12. Interceptors in Struts2
13. Struts2 Execandwait Interceptor
14. Struts2 Custom Interceptor
15. Struts2 Result type
16. Struts2 Redirect result type
17. Struts2 Validation Framework
18. Struts2 Validation by Built in validators
19. Struts2 i18n
20. Struts2 Zero Configuration by convention approach
21. Struts2 Zero Configuration by annotation Approach
22. Dispatch Action Functionality in Struts2
23. Dynamic method invocation in Struts2
24. Struts2 UI Tags
25. Struts2 Control Tags
26. Struts2 Data Tags
27. Struts2 and tiles integration
28. Struts2 and Quartz2 Schedular
29. Struts2 Interview Questions and Answers

The DispatchAction Functionality is a way of grouping the related actions into a single action class. In struts 1 DispatchAction class provides this functionality but in struts 2 every action class by default provide this functionality. To achieve this functionality in struts 2 we have to define the actions with the different names but having the same signature as execute method.

Example:

test.jsp

<%@ taglib uri="/struts-tags" prefix="s"%>
<html>
 <head>
     <title>Struts 2 dispatch action functionality example</title>
 </head>
 <body>
  <h3>This is a dispatch action functionality example.</h3>
 
  <s:form action="TestAction">
   <s:submit value="Submit"/>
   <s:submit value="Show" action="testShow"/>
  </s:form>
 
 </body>
</html>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
 xmlns="http://java.sun.com/xml/ns/javaee" 
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
 http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
 
 
  <filter>
  <filter-name>struts2</filter-name>
  <filter-class>
         org.apache.struts2.dispatcher.ng.
         filter.StrutsPrepareAndExecuteFilter
        </filter-class>
 </filter>
 
 <filter-mapping>
  <filter-name>struts2</filter-name>
  <url-pattern>/*</url-pattern>
 </filter-mapping>
 
 <welcome-file-list>
   <welcome-file>test.jsp</welcome-file>
 </welcome-file-list>
 
</web-app>

struts.xml

<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">
 
<struts>
 
 <package name="default" extends="struts-default">
  <action name="TestAction" 
                           class="com.javawithease.action.TestAction">
   <result name="success">/welcome.jsp</result>
  </action>
 
  <action name="testShow" method="show" 
                           class="com.javawithease.action.TestAction">
     <result name="success">/welcome.jsp</result>
  </action>
 
 </package>
 
</struts>

TestAction.java

import com.opensymphony.xwork2.ActionSupport;
 
/**
 * This class is used as an action class.
 * @author javawithease
 */
public class TestAction extends ActionSupport {
 private String message;
 
 public String execute(){
  setMessage("execute method is called.");
  return SUCCESS;
 }
 
 public String show(){
  setMessage("show method is called.");
  return SUCCESS;
 }
 
 public String getMessage() {
  return message;
 }
 
 public void setMessage(String message) {
  this.message = message;
 } 
}

welcome.jsp

<%@ taglib uri="/struts-tags" prefix="s"%>
<html>
 <head>
     <title>Struts 2 dispatch action functionality example</title>
 </head>
 <body>
  <h3>This is a dispatch action functionality example.</h3>
 
  <s:property value="message" />
 
 </body>
</html>