Building website according to the MVC model

[jprog]

Hi, guys

i created a website, but the presentation and the business logic aren't separated. In the jsp pages there is a connection to the database and retrieving data from the database.
What will be the structure of my site according to the MVC model.

JSP->ControllerServlet1->Bean1
JSP->ControllerServlet2->Bean2
JSP->ControllerServlet3->Bean3

or something else.

If you have more information about MVC model i will be appreciate. :)

[Tolls]

The client makes calls to your server.
These calls are handled by Servlets, which will generally make calls to a business layer. Servlets should simply control the flow, that is receive request, farm them off to a service layer, then forward to a suitable JSP when that service has finished its job.

So it's:

Client -> Servlet -> Business Layer
                  -> JSP -> Client

[jprog]

Thanks for the answer. There is one Controller Servlet or can be many Controller Servlets.

[Tolls]

Many.
It's easier to break up the work that way, and to test individual bits of functionality.
I click button X on the front end, that fires a call to servlet X on the back end. Button Y calls servlet Y.

If there's a set of closely related operations then you might stick them in one Servlet, but I personally rarely see the advantage in that.

[jprog]

In my case i'm using web.xml to store database parameters(driver, server, username, password, port). I have a servlet for retrieving parameters from the web.xml, model class which makes connection to the database and close the connection. And beans for every query to the database. Is this the right way?

[Tolls]

Your model should know nothing about the database.
There will be a database layer, essentially a set of DAOs, which will do the persisting.

I'd stick the parameters in a properties file myself, which the database layer will then look at. Again, the servlet should know nothing about any databases. It should pass control into a business layer that then actually does the processing.

Client -> Servlet -> Service class (does the processing) -> calls DAOs (does the database interaction).

[cld71]

You can also use filters and listeners to do your business layer, and pass the data through the application, session, or request scope attributes to your servlet or JSP pages.

Client -> Servlet/JSP -> Filter -> Filter -> ... -> Listener -> DAO -> Database

Just remember you must declare the JSP with as a servlet in your web.xml file in order to be able to use a filter, because of the filter mappings.