Building a sample Web App with STRUTS part 2

6. Let us compile this java file. First let us set a parameter in NetBeans - to set target directory where the java files will be compiled (classes will be stored). Go to tools - options compiler types- external compilation (the external compiler, javac is typically the default compiler. Set the target directory to StrutsNetBeansSample /WEB-INF/classes. Click on the file (TestFormBean.java) in the explorer window and click build - > compile from main menu. The o/p window should show a message like 'Finished TestFormBean. Now we have a form bean we need an Action class that will take this form bean - use the ipString entered by user to pass to the next page.

7. Lets create the TestActionHandler.java under src/com/openstack/struts/testapp. Here is the class definition:

package com.openstack.struts.testapp;


import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Locale;
import java.util.Vector;
import javax.servlet.*;
import javax.servlet.http.*;
import org.apache.struts.action.*;

import com.openstack.struts.testapp.*;

public final class TestActionHandler extends Action {

  public ActionForward perform(ActionMapping mapping,
  ActionForm form,
  HttpServletRequest request,
  HttpServletResponse response)
throws IOException, ServletException {


 
       
     TestFormBean tform = 

(com.openstack.struts.testapp.TestFormBean) form;
         
     String tmpStr = "Welcome " + tform.getIpString() + " !";
     tform.setIpString(tmpStr);
            
     request.setAttribute("TestFormBean", tform);
          
 return (mapping.findForward("success"));

    }


}

As you can see all we are doing is taking the ipString (where user will enter his / her name) and then generating a welcome message. Then we reset the ipString with this complete message and set the bean back in the request object. Finally we forward the control to the 'success' handler of this action.

Look at the 'perform' method. It returns 'ActionForward' that forwards the action to the next page (or handler).

The part 'return (mapping.findForward("success"))' will instruct struts to go to next step.

Let"s look at how we specify this 'next step' in struts: Open the struts.config from the WEB-INF directory. Look at the action mapping:

<action    path="/TestAction"
           type="com.openstack.struts.testapp.TestActionHandler"
           name="TestFormBean"
           scope="request"
           validate="false">
      <forward name="success"     path="/TestResult.jsp" />
    </action>

The TestAction (from the TestFormPage.jsp) maps to TestActionHandler class under com.openstack.struts.testapp. In our TestFormPage.JSP we have specified the submit action in the form as "TestAction". So when the form submits STRUTS will read this file to evaluate 'TestAction' and call the perform method in:
com.openstack.struts.testapp.TestActionHandler Class. 
Finally the mapping.findForward("success")) will forward the request to TestResult.jsp, based on the following line in struts.config

<forward name="success"
path="/TestResult.jsp" /> 

So, in summary STRUTS will do the following tasks:

• Copy user entered values into a form bean.
• Call the action handler passing the form bean.
• Facilitate screen flow using the action mapping.