Introduction to ModelDriven interface with example

Introduction to ModelDriven interface with example
Posted on: November 24, 2010 at 12:00 AM

In this tutorial you will learn about the ModelDriven interface and to use it in writing your own Action class

Model Driven Interface With Example

Model driven interface is an Action interface which provides a model object to pushed in to the value object in addition to action. In order to create a model driven action your class should extend ActionSupport class and also implement the ModelDriven interface. This interceptor is already present into the default stack.

The Model driven interface provides a single method getModel() this allows the model to be pushed into the value stack instead of action itself.

An example given below illustrates the model driven interface

StudentAction.java

<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
</head>
<body>
<h1>ModelDriven Interface Example</h1>

<h2>Add Student</h2>
<s:form action="studentAction" >
<s:textfield name="studentName" label="Name" value=""/>
<s:textfield name="studentAge" label="Age" value=""/>
<s:submit />
</s:form>

</body>
</html>

studentInfo.jsp

<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
</head>
<body>
<h1>ModelDriven Interface Example</h1>

<h2>Student Details</h2>
Name : <s:property value="studentName" /><br>
Age : <s:property value="studentAge" /><br>

</body>
</html>

StudentAction.java

package net.roseindia;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;
 
public class StudentAction extends ActionSupport 
	implements ModelDriven{
 
	StudentBean student = new StudentBean();
 
	public String execute() throws Exception {
 
		return SUCCESS;
 
	}
 
	public Object getModel() {
 
		return student;
	}
}

StudentBean.java

package net.roseindia;
public class StudentBean{
	 
	String studentName;
	int studentAge;
	public String getStudentName() {
		return studentName;
	}
	public void setStudentName(String studentName) {
		this.studentName = studentName;
	}
	public int getStudentAge() {
		return studentAge;
	}
	public void setStudentAge(int studentAge) {
		this.studentAge = studentAge;
	}
 	
}

Now Mapping for the above Action class and JSP files in struts.xml

struts.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>

<constant name="struts.enable.DynamicMethodInvocation" value="false" />
<constant name="struts.devMode" value="false" />

<package name="roseindia" extends="struts-default">


<action name="addStudent" 
class="net.roseindia.StudentAction" >
<result name="success">/jsp/addStudent.jsp</result>
</action>

<action name="studentAction" 
class="net.roseindia.StudentAction" >
<result name="success">/jsp/studentInfo.jsp</result>
</action>

</package>

</struts>

When you run this application it will display message as shown below:

Download this example code

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