Although the application developed in the previous section was fairly easy to
develop, the resulting code isn't very maintainable. One of the JSPs has both
business logic and presentation logic embedded in it. It is considered a best practice
for JSPs to have only presentation logic, and keep the business logic elsewhere.
One common way to approach this problem is to use the Model-View-Controller
(MVC) design pattern. This pattern provides a clean separation of concerns,
providing artifacts that solely act as data (model), while other artifacts are
solely responsible for displaying the data (view) and another artifact or artifacts
is responsible for manipulating the data and transferring control to the view
(controller). In Java web applications, JSPs typically act as view, servlets act as
controllers, and custom JavaBeans act as the model.
In this section we will modify the application we developed previously so that it
follows this pattern.
Adding a Servlet to our Application
NetBeans provides functionality that allows us to easily create a servlet. In order to
create our servlet, we need to go to File| New File , choose Web from the Categories
list, then Servlet from the File Types list.