Question

I am crawling through a servlet site and in almost every doPost I encounter code like this :

@Override
protected void doPost(HttpServletRequest request,
        HttpServletResponse response) throws ServletException, IOException {
    // set encoding to UTF-8
    if (request.getCharacterEncoding() == null)
        request.setCharacterEncoding("UTF-8");
    // TODO : this may be needed in doGet too ?????????
    response.setCharacterEncoding("UTF-8");

    // check if session exists
    boolean sessionExists = request.isRequestedSessionIdValid();
    HttpSession session = request.getSession();

    if (!sessionExists)
        session.setMaxInactiveInterval(1000);

    // if session does not exist we create it
    ServletContext context = session.getServletContext();
    Integer numSessions = (Integer) context
            .getAttribute("numberOfSessions");
    if (numSessions == null)
        context.setAttribute("numberOfSessions", 1);
    else if (!sessionExists)
        context.setAttribute("numberOfSessions", ++numSessions);
}

Would it be a good idea to create a BaseController class and move this code there – and should I move it in the init() method or in the doPost() – and then call super.doPost ? Also there are lines like session.setAttribute("photo", photo); in some of the servlets. Would it then be a good idea to have a session field in the BaseController – which if I understand things correctly should be volatile.

I am new to all this.

Thanks

Answer 1

You can move setting the request character encoding to a helper method and call it from doPost. Also check if your code behaved correctly in case that the encoding is set to something else than utf-8.

On the other hand, the session stuff is a bit weird. If you want to keep track of the number of sessions, remove all that and use javax.servlet.http.HttpSessionListener. It is more elegant and you will have your code in a single place.

If you need to keep track of variables that belong to a session, keep using the HttpSession class, do not save them in a field in the controller.