Struts: The basic Web Struts Application

Before read this article, be sure you know What is the Strusts Framework?
So, this article will explaint how to build an simple Web Struts Application?. It have many program support easily-build-int
Struts such as: MyEclipse, NetBean ... But, the basic guide for building Struts is very helpful for new to Struts and Java programming. This example will help you understand Struts in detail. I'll create new user interface to accept Name and Email address from user-input. In this case, form input was create with a basic JSP template called input.jsp and the success page will be success.jsp. Action class is just forwarding it to the sucess.jsp.

Action Form for struts (MODEL).



So, what's ActionForm? It's JavaBean that extends org.apache.struts.action.ActionForm. This bean will be maintains the session state for web application, data input from form at client-side will be automatically added as the object in server-side. In this case, i'll create new ActionForm name as GuestForm.java

• GuestForm.java

package prlamnguyen.struts.form;

import javax.servlet.http.HttpServletRequest;
import org.apache.struts.action.*;


/**
* @author Nguyen, Lam Duy
* @link http://prlamnguyen.blogspot.com/2007/02/java-tutorial-basic-web-struts.html
*/

/**
 * Form bean for the Guest entry.
 *
*/
public class GuestForm extends ActionForm
{
  private String name=null;
  private String emailAddress=null;

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

  public String getName(){
    return this.name;
  }

  public void setEmailAddress(String emailAddress){
    this.emailAddress=emailAddress;
  }

  public String getEmailAddress(){
    return this.emailAddress;
  }


  /**
   * Reset method will be used for reseting all data to default is null.
   *
   * @param mapping The mapping used to select this instance
   * @param request The servlet request we are processing
   */
  public void reset(ActionMapping mapping, HttpServletRequest request) {
     this.name=null;
     this.emailAddress=null;
  }

  /**
   * Validate method to vailde the data inputed from form at client-side. It's be
   * excute at Server-side. Set return to null if you not want to validate the
   * form input
   *
   * @param mapping The mapping used to select this instance
   * @param request The servlet request we are processing
   * @return errors
   */
  public ActionErrors validate(
      ActionMapping mapping, HttpServletRequest request ) {
      //In this case, i'll not validate form, i want this article simply
       //The validate form for struts will be posted later.
      return null;
  }

}

Action Class for Struts (Controller)





Next step, create Action class, Action class is a Controller which receives the request, looks up the mapping for this request, and forwards it to an action. I'll create new class file name GuestAction.java which simply forward the request the success.jsp.

• GuestAction.java

package prlamnguyen.struts.action;


import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;



/**
* @author Nguyen, Lam Duy
* @link http://prlamnguyen.blogspot.com/2007/02/java-tutorial-basic-web-struts.html
*/

public class AddressAction extends Action
{
  /**
  * Method execute
  * @param mapping
  * @param form
  * @param request
  * @param response
  * @return ActionForward
  * @throws Exception
  */
  public ActionForward execute(ActionMapping mapping, ActionForm form,
                    HttpServletRequest request, HttpServletResponse response) throws Exception{
       ActionForward forward = new ActionForward();
       forward = mapping.findForward("success");
      return forward;
  }
}

Now, create config file for Struts, default name for struts config file is struts-config.xml. Add the following lines in the struts-config.xml file:

• struts-config.xml

<?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.2//EN"
                                             "http://struts.apache.org/dtds/struts-config_1_2.dtd">
<struts-config>



 ...


 <!--
Define form-bean class.
-->

 <form-beans >
 <form-bean name="guestForm" type="prlamnguyen.struts.form.GuestForm" />
</form-beans>


 ...

 <action-mappings >

 <!--
These line below for handling the action "/guestInput.do".
-->
  <action
     attribute="guestForm"
     input="/input.jsp"
     name="guestForm"
     path="/guestInput"
     scope="request"
     validate="false"
     type="prlamnguyen.struts.action.GuestAction">

     <forward name="success" path="/success.jsp" />
 </action>
</action-mappings>

 ...

 </struts-config>

The action *.do have to define in web.xml. Add following code into web.xml file. This step can be ignored when you use MyEclipse or NetBean ... to add Struts. In this case, i'll do it for you.

• web.xml

<?xml version="1.0" encoding="UTF-8"?>
 <web-app xmlns="http://java.sun.com/xml/ns/j2ee" 
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
          version="2.4" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee   
          http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">




 ...


 <!--
Add these line for using struts in web application, 
    default code can be generated by other program such as: MyEclipse, NetBean....
-->
  <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>3</param-value>
</init-param>
<init-param>
<param-name>detail</param-name>
<param-value>3</param-value>
</init-param>
<load-on-startup>0</load-on-startup>
</servlet>


 ...


  <servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>


 ...


 </web-app>

JSP for input and Display (VIEW).



Last, create the new jsp page for form input which is our form for entering the details and jsp page for success message, in Struts Config, input-form file was defined as input.jsp and success page is success.jsp.

• input.jsp

<html:form action="/guestInput">
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td>Name:</td>
<td><html:text property="name"/></td>
</tr>
<tr>
<td>Email Address:</td>
<td><html:text property="emailAddress"/></td>
</tr>
</table>
<div align="center"> 
<html:submit/>&nbsp;&nbsp;<html:reset/>
</div>
</html:form>  

• success.jsp

  <%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<html>
<head>
<title>Success</title>
</head>
<body>
       Input successful !

 </body>
 </html>  

Correct me if I'm wrong.

Regard!

© Nguyen, Duy Lam 2008