Understanding The Struts ActionForm Class

An ActionForm is a JavaBean which extends the org.apache.struts.action.ActionForm. The ActionForm object is automatically populated on the server side with data entered from a form on the client side and ActionForm maintains the session state for the web application and .

At first,we will first create the class called AddressForm which extends the ActionForm class.The following code describes ActionForm.java.

package academictutorials;

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

/**
* Form bean for the Address Entry Screen.
*
*/
public class AddressForm extends ActionForm
{
private String name=null;
private String address=null;
private String emailAddress=null;

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

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

public void setAddress(String address)
{
this.address=address;
}

public String getAddress()
{
return this.address;
}

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

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

/**
* Reset all properties to their default values.
*
* @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.address=null;
this.emailAddress=null;
}

/**
* Reset all properties to their default values.
*
* @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 )
{
ActionErrors errors = new ActionErrors();

if( getName() == null || getName().length() < 1 )
{
errors.add("name",new ActionMessage("error.name.required"));
}
if( getAddress() == null || getAddress().length() < 1 )
{
errors.add("address",new ActionMessage("error.address.required"));
}
if( getEmailAddress() == null || getEmailAddress().length() < 1 )
{
errors.add("emailaddress",new ActionMessage("error.emailaddress.required"));
}
return errors;
}
}

The above class validates Address Form data and populates it. To validate user inputs,the validate() method is used . Error messages are added to ActionMapping object,if any or all of the fields on the form are blank . Note that in the next version ActionError will be removed and now we are using ActionMessage class.

Now we will create the model part of the application called Action class. In our action class simply forwards request to the Success.jsp. The following example is the code for AdessAction.java class

package academictutorials;

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;

public class AddressAction extends Action
{
public ActionForward execute(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws Exception
{
return mapping.findForward("success");
}
}

In the struts-config.xml,we have to create an entry for form bean. In struts-config.xml file,add the following lines :

<form-bean name="AddressForm" type="academictytorials.AddressForm"/>

In struts-config.xml file,add the following line for handling the action "/Address.do":

For entering the address details,create the Address.jsp page which is our form . Code for Address.jsp is as follows:

<%@ taglib uri="/tags/struts-bean" prefix="bean" %>
<%@ taglib uri="/tags/struts-html" prefix="html" %>

<html:html locale="true">

<head>

<title><bean:message key="welcome.title"/></title>

<html:base/>

</head>

<body bgcolor="white">

<html:form action="/Address">

<html:errors/>

<table>

<tr>

<td align="center">
<font size="4">Please Enter the Following Details</font>
</tr>
<tr>
<td align="right">
Name
</td>
<td align="left">
<html:text property="name" size="30" maxlength="30"/>
</td>
</tr>
<tr>
<td align="right">
Address
</td>
<td align="left">
<html:text property="address" size="30" maxlength="30"/>
</td>
</tr>

<tr>
<td align="right">
E-mail address
</td>
<td align="left">
<html:text property="emailAddress" size="30" maxlength="30"/>
</td>
</tr>
<tr>
<td align="right">
<html:submit>Save</html:submit>
</td>
<td align="left">
<html:cancel>Cancel</html:cancel>
</td>
</tr>
</table>
</html:form>
</body>
</html:html>

At first,the user enters the values in the form and then click on submit form. On the server side,form validation is done.The Eeror message is displays on the jsp page . Use the following code to display the error on the jsp page the <html:errors/> > tag is used. The <html:errors/> tag displays all the errors in one go. To create text box the <html:text .../> nbsp;

e.g.

<html:text property="address" size="30" maxlength="30"/>

To enter the address,the above tag is used.In form-bean,the address is retrieved from and later stored in the property named address. Using <html:submit>Save</html:submit> tag we ca create the submit button and using <html:cancel>Cancel</html:cancel> tag we can create Cancel button.

To create a link for testing the Address.jsp form,add the following line in index.jsp.

<html:link page="/pages/Address.jsp">Test Address Form</html:link>

To test the newly created screen,build the application and click on the Test the Address Form link on the index page .

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