Struts DispatchAction Tutorial with Example in Eclipse.

Are you bugged of creating separate action classes for some common set of functionality in your Struts application? Feeling pain in managing all those hundreds of Action classes in your project? Don’t worry, cheers..!! DispatchAction is for you.

DispatchAction is one of the Struts built-in action that provides a mechanism that facilitates having a set of related functionality in a single action instead of creating separate independent actions for each function.

Let us create a sample example that uses DispatchAction and implement certain functionality of our project. Before that, I assume you have working knowledge of Struts application. If you don’t, Read this tutorial about A Hello World Struts project and get some basics about Struts application.

Also, I assume you have already got a Struts application and you want to add Dispatch Action into it. So let us start with our example.

Step 1: Create DispatchAction class file.

Create an Action class called UserManagementAction and extend it with class org.apache.struts.actions.DispatchAction. Copy following code into it.

package net.viralpatel.struts.helloworld.action;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.actions.DispatchAction;

public class UserManagementAction extends DispatchAction {
	
	public ActionForward create(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {
	
		request.setAttribute("message", "User created successfully");
		
		return mapping.findForward("success");
	}



	public ActionForward delete(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {
	
		request.setAttribute("message", "User deleted successfully");
		
		return mapping.findForward("success");
	}



	public ActionForward update(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {
	
		request.setAttribute("message", "User updated successfully");
		
		return mapping.findForward("success");
	}



	public ActionForward block(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {
	
		request.setAttribute("message", "User blocked successfully");
		
		return mapping.findForward("success");
	}
}

In above code, we have created separate methods (create(), delete(), update() and block()) for each functionality. Also note that the method signature of these methods are exactly similar to the execute() method of Action class file.

public ActionForward delete(ActionMapping mapping, ActionForm form,
		HttpServletRequest request, HttpServletResponse response)
		throws Exception { }

Step 2: Create a mapping for action in struts-config.xml file.

Open your struts-config.xml and copy following action mapping entry in it.

We have added an extra attribute in <action> tag, parameter=”parameter”. DispatchAction will read a request parameter called “parameter” and its value will decide the method to be called. Suppose you have a request parameter “parameter” with value “create”, Dispatch Action will call create() method from your Action file.

Step 3: Create JSPs for viewing the application.

Create two JSP files UserManagement.jsp and UserSuccess.jsp and copy following code into it. UserManagement.jsp will display a menu for selecting action to be taken. UserSuccess.jsp will just print the appropriate action taken by the Action class.

UserManagement.jsp

UserSuccess.jsp

In UserManagement.jsp, we have created links using <html:link> tag and passed a parameter “parameter” with values create, delete, block etc. This value is fetched by the Dispatch Action and is used to call corresponding method in Action class. Thus if we click Update User link, a parameter update will be passed to the action class and corresponding update() method will be called by framework.

Step 4: Run the application.

Compile and Run the project using Eclipse or Ant and open UserManagement.jsp file in your favorite browser.
Struts Dispatch Action Example Tutorial

Click the link Create User or Delete User etc. and see the output.

struts-dispatchaction-example-create

struts-dispatchaction-example-delete

Get our Articles via Email. Enter your email address.

You may also like...

32 Comments

  1. Carlos says:

    Excelente manual!!! Muchas gracias
    Thank’s

  2. Viral Patel says:

    @Carlos: Thanks for the good words :) Do read other articles about Struts and also feel free to subscribe for the newsletter.

  3. Kumar says:

    If we have a from in which we are trying to use Dispatch action, What is the best way of implementing it. I have used the parameter in action tag of a Form, something like, action=’dynaAction.do?param=ParamValue’. depends on the action selected, we can change the URL for the form. Do you have any other approach in doing this.

    Thanks,
    Kumar

  4. neelam says:

    hello viral
    my question is that ,cannot we use buttons instead of html-link ??…..
    b’coz when I m using buttons instead of links I m getting following error
    ” Request[/ClientForm] does not contain handler parameter named ‘parameter’. This may be caused by whitespace in the label text”….

    • Viral Patel says:

      Hi Neelam,
      The possible reason of error in case of using button instead of link is that it is not able to get parameter to decided which method to trigger in Struts. Create a field (hidden or select box) in your form with name=”parameter” and set its value to method name that you want to call.

      Hope this will solve the issue.

  5. neelam says:

    hi viral
    I have tried this using
    **********jsp…************

    ***********struts-config…*************

    ********ApplicatonResources…***********
    label.save=save

    *********************ClientAction_Buttons.java***************************
    protected Map getKeyMethodMap() {
    Map map = new HashMap();
    map.put(“label.add”, “add”);
    map.put(“label.edit”, “edit”);
    map.put(“label.search”, “search”);
    map.put(“label.save”, “save”);
    return map;
    }

    public ActionForward add(
    ActionMapping mapping,
    ClientForm form,
    HttpServletRequest request,
    HttpServletResponse response) throws Exception {
    System.out.println(“You are in add function.”);
    return mapping.findForward(“add”);
    }
    **************

    but now I m getting the following error
    javax.servlet.ServletException: DispatchMapping[/ClientForm] does not define a handler property..
    can you please tell me what I doing wrong here???
    Regards
    Neelam

    • Amyth says:

      “javax.servlet.ServletException: DispatchMapping[/ClientForm] does not define a handler property..
      can you please tell me what I doing wrong here???”

      Your add() method is having a parameter of type ClientForm, Replace the ClientForm with ActionForm and check if it works.

  6. Duy Khoa says:

    I think this is not a good solution. In some situations it is not useful and cannot be implemented. How can we extend both ActionSupport and DispatchAction. In modern OOP, a class should be have one and only one superclass.

  7. pbchowdary says:

    Hi viral,i am daily visitor of u r website,u r posts are very good and i am following the same.Me working as a s/w professional in a small organization.could you pls post one sample project with dao,vo,action,domain layer.

  8. Sky says:

    Hi Neelam,

    I guess, now you have used a hidden field named “parameter” on the jsp, but you have not
    created a property by the name “parameter” on the corresponding form for that jsp.

  9. srikanth says:

    if we use dispatch action how many formbean(Action Forms) classes we have to create.

  10. ADITYA SINGH says:

    if i want to put a specific method of dispatch action in thread, then what will i have to do .

  11. Akash Gupta says:

    Go through this link :
    http://www.raistudies.com/struts-1/dispatchaction/
    Realy good illustration of DispatchAction with real life example and code.

  12. asdf says:

    nice tutorial. this is exactly what i required.

  13. @ Viral :) Excellent Work! Very Good!! I Easily Understood the concept.. thank You Viral Patel

  14. Niketa says:

    Hello viral
    I would like to know what to do in case i have three buttons add, update , delete..
    Then how do i pass a parameter to action class.

  15. senthilnathan says:

    Well said.But my doubt is ActionForm need or not?

  16. Shrikant Kale says:

    I have done the same prog. with buttons and using the scope but problem is that its not showing any result
    —————————————————————————————————————-

    Student Id :
    Student Name :

    ————————————————————————————————————————-

    ———————————————————————————————————————–
    public class CustomerDispatchForm extends org.apache.struts.action.ActionForm {

    protected String sid;
    protected String name;

    public String getSid() {
    return sid;
    }

    public void setSid(String sid) {
    this.sid = sid;
    }

    public String getName() {
    return name;
    }

    public void setName(String name) {
    this.name = name;
    }

    }

    —————————————————————————————————————————

    public class CustomerDispatchAction extends DispatchAction {

    String sid;
    String name;

    public ActionForward saveCustomer(ActionMapping mapping,ActionForm form,HttpServletRequest request,HttpServletResponse response) {

    CustomerDispatchForm fm=(CustomerDispatchForm) form;

    sid=fm.getSid();
    name=fm.getName();

    request.setAttribute(“Student ID”, sid);
    request.setAttribute(“Student Name”, name);

    return mapping.findForward(“success”);
    }

    public ActionForward deleteCustomer(ActionMapping mapping,ActionForm form,HttpServletRequest request,HttpServletResponse response) {

    CustomerDispatchForm fm=(CustomerDispatchForm) form;

    sid=fm.getSid();
    name=fm.getName();

    request.removeAttribute(“sid”);
    request.removeAttribute(“name”);

    return mapping.findForward(“success”);
    }

    }
    ————————————————————————————————————————–

    ———————————————————————————————————————-

    action
    org.apache.struts.action.ActionServlet

    config
    /WEB-INF/struts-config.xml

    debug
    2

    detail
    2

    2

    action
    *.do

    30

    Input.jsp

    /WEB-INF/struts-bean.tld
    /WEB-INF/struts-bean.tld

    /WEB-INF/struts-html.tld
    /WEB-INF/struts-html.tld

    /WEB-INF/struts-logic.tld
    /WEB-INF/struts-logic.tld

    /WEB-INF/struts-nested.tld
    /WEB-INF/struts-nested.tld

    /WEB-INF/struts-tiles.tld
    /WEB-INF/struts-tiles.tld

    ======================================================================

    Help Me to understand the error.

  17. john says:

    Nice one… Saved my time….

  18. sweetu514 says:

    Hi viral, when I try this example , I get the 404- Resource not found error, what could be the reason ?

  19. Kailash says:

    Hi Viral

    Thanks a lot!

    I have one query. Can We hide method name in URL?

    I tried hard!but not success-ed!

    Thanks in Advance.

    Kailash

  20. vijay says:

    Hi Viral,

    I am a new bee in struts. i am using 1.3 version of struts.

    Can we have multiple execute methods in one acton class in struts if we are not using DispatchAction mechanism ?

    What will happen if we try to use multiple execute methods ?

    Your help is appreciated.

    Awaiting for your answer ASAP.
    Regards,
    Vijay

  21. Saimanraj says:

    Hi Viral,
    thank you soo much for this super manual.. Its very easy to understand and it is very clear.

  22. samkhan says:

    Hi Viral
    I m getting the following issue is I click on any of the link on the first page load
    Create User | Delete User | Update User | Block User
    url is: http://localhost:8080/DA/UserManagement.jsp

    type Status report
    message Servlet action is not available
    description The requested resource is not available.

  23. Arti says:

    hi viral ,
    I have used DispatchActon class and i m getting error as DispatchMapping[/getEmp] does not define a handler property.Here is my code.Please suggest smthing to solve this error.
    index.jsp

    <html:link href="getEmp.do?action=getEmp">Get Employee</html:link>
            <html:link href="getEmp.do?action=newEmp">New Employee</html:link>
    

    dispatchAction.java

    public class dispatchAction extends DispatchAction {
    
      
    
         
        private static final String SUCCESS = "success";
    
        public ActionForward getEmp(ActionMapping mapping, ActionForm form,
                HttpServletRequest request, HttpServletResponse response)throws Exception{
            
            request.setAttribute("method", "getEmp is called");
            return mapping.findForward(SUCCESS);
        }
        
         public ActionForward newEmp(ActionMapping mapping, ActionForm form,
                HttpServletRequest request, HttpServletResponse response)throws Exception{
            
            request.setAttribute("method", "newEmp is called");
            return mapping.findForward(SUCCESS);
        }
    
    

    struts-config.xml

    displayTest.jsp

    <bean:write name="method"/>
    

    thanks in advanced

  24. thiyagarjan says:

    I’m new to struts while creating an appln I met with some issue I got cleared with this link thanks a lot dear

  25. lalit says:

    hii…I want to know that how to call create ,edit and delete in action by dispatcg action?

  26. vinodh says:

    Hi,
    thanks for this. this helped me to explain same functionality in interview .
    regards
    vinodh

  27. uttam kumar says:

    i need two different form in one jsp page,which has only one front controller servlet , and two different beans .. in struts 1. . plz help me

  28. ramesh says:

    The below code is returning null .

    i believe you need to store the ‘message’ to some variable and print it. correct me if i am wrong.

  29. Hi Viral,

    the below Code is not working , “message” is printing as null.

    <font color="blue"><h3><%= request.getAttribute("message") %></h3></font> 
    

    I used like this,now it is working , kindly reckeck

    <font color="Green"><h3>${message} </h3></font> 
    

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.