MVC
Model 1¶
Early Java web applications had the JSP as the center of the app. Its responsibilities included: * Parsing HTTP request parameters. * Calling classes that perform business logic with JavaBeans, which model data. * Controlling the navigation of the site. * Controlling what data the user sees. * Displaying the HTML "view" to the user.
This JSP-centered architecture is known as Model 1.
JavaBean¶
A Java class with a no-arg constructor and get/set methods.
business logic¶
Code or processing that handles what happens between the presentation logic (what the user interacts with) and data logic (what the database interacts with).
Model View Controller (MVC)¶
Later applications separate the display code (JSP) from flow control (navigation) and interacting with the model (business logic).
A servlet is added to control and coordinate interactions between the model and the view.
This three-layered architecture is the Model-View-Controller design pattern.
- Model - JavaBeans, Java classes, and data.
- View - JSP pages; things the user sees.
- Controller - servlet coordinating the model and view.