Struts 1.3 Session Management

I am using the session object to store the logged in user id in signUpAction.java

HttpSession session = request.getSession();
if(login>0&&candy>0){                
    session.setAttribute("username", val.getUsername());
    result = "success";    
}

then i forward the user to a jsp page corresponding to his/her id.

User name is `<bean:write name="signUp" property="username"/>`

The problem is that when the user clicks the back button, he/she logs back out(without clicking any logout button). I want a session to be maintained until the user clicks on the logout button. And how do i check whether the user is logged in on every page? I am using Struts 1.3 and I'm new to it. Please help me. I'm trying to develop a Job Portal web app as a project.

Solution

Here is how I did it. In my validateAction class file

HttpSession session = request.getSession();
session.setAttribute("username", val.getUsername());

After that on every JSP page i wrote

<c:choose>
        <c:when test="${not empty sessionScope.username}">
            // all the codes goes here
        </c:when>
        <c:otherwise>
            <h1>Please Login First.</h1>
        </c:otherwise>
</c:choose>

And in the master page I included

<body onload="window.history.forward(1);">

so even when the user clicks the back button the browser won't load the last cached page.

and when the user clicks the logout button, I call my invalidateAction class file

HttpSession session = request.getSession();
session.removeAttribute("username");