Servlets : HttpSessionBindinglistener Demo

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HttpSessionBindingListenerDemo Project Dir Structure

HttpSessionAttributeTestServlet.java

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class HttpSessionAttributeTestServlet extends HttpServlet
{
    private static final long serialVersionUID = 1L;

    public void init() throws ServletException
    {
        System.out.println("-----------------------------------------");
        System.out.println(" Init method is called in "
                + this.getClass().getName());
        System.out.println("--------------------------------------");
    }

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException
    {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();

        HttpSession httpSession = request.getSession();

        sleep();

        User user = new User("Ram", 43);
        httpSession.setAttribute("userinfo", user);

        sleep();

        httpSession.invalidate();

        out.println("This is the example of HttpSessionBindingListener");

    }

    private void sleep()
    {
        try
        {
            Thread.sleep(10000);
        }
        catch (InterruptedException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public void destroy()
    {
        System.out.println("-----------------------------------------");
        System.out.println(" destroy method is called in "
                + this.getClass().getName());
        System.out.println("-----------------------------------------");
    }

}

User.java

import javax.servlet.http.HttpSessionBindingEvent;
import javax.servlet.http.HttpSessionBindingListener;

public class User implements HttpSessionBindingListener
{

    private String name;
    private int age;

    public User(String name, int age)
    {
        super();
        this.name = name;
        this.age = age;
    }

    public User(String name)
    {
        this.name = name;
    }

    public String getName()
    {
        return name;
    }

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

    public int getAge()
    {
        return age;
    }

    public void setAge(int age)
    {
        this.age = age;
    }

    @Override
    public void valueBound(HttpSessionBindingEvent httpSessionBindingEvent)
    {
        System.out.println("\n###################################\n");

        System.out.println("valueBound method has been called in "
                + this.getClass().getName());

        System.out.println("Added/Replaced Attribute Name ="
                + httpSessionBindingEvent.getName() + ",value = "
                + httpSessionBindingEvent.getValue());

        System.out.println("\n#####################################\n");

        /*
         * if particular Attribute is added/replaced, based on that if you want
         * to perform any operation then you can do it here.
         */

    }

    @Override
    public void valueUnbound(HttpSessionBindingEvent httpSessionBindingEvent)
    {
        System.out.println("\n###################################\n");

        System.out.println("valueUnbound method has been called in "
                + this.getClass().getName());

        System.out.println("Removed Attribute Name ="
                + httpSessionBindingEvent.getName() + ",value = "
                + httpSessionBindingEvent.getValue());

        System.out.println("\n#####################################\n");

        /*
         * if particular Attribute is removed, based on that if you want to
         * perform any operation then you can do it here.
         */

    }

    @Override
    public String toString()
    {
        return "User [name=" + name + ", age=" + age + "]";
    }

}

web.xml

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    metadata-complete="true" version="3.0">

    <display-name>HttpSessionBindingListenerDemo</display-name>

    <description>
        This is a simple web application with a source code organization
        based on the recommendations of the Application Developer's Guide.
    </description>

    <servlet>
        <servlet-name>HttpSessionAttributeTestServlet</servlet-name>
        <servlet-class>HttpSessionAttributeTestServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>HttpSessionAttributeTestServlet</servlet-name>
        <url-pattern>/listenerTest</url-pattern>
    </servlet-mapping>

</web-app>

index.html

<html>
<body>
    <a href="listenerTest">listenerTest</a>
</body>
</html>

Environment Used 

JDK version :1.7.0_51
Tomcat version : 7.0.50 

To Download HttpSessionBindingListenerDemoApp Project Click the below link

https://sites.google.com/site/javaee4321/servlets/HttpSessionBindingListenerDemoApp.zip?attredirects=0&d=1

See also:

Servlets Tutorial

All Design Patterns Links