Java EE Architecture

The Java EE architecture typically consists of the following layers:

1, Domain object layer: This layer is mainly composed of abstract object model (also known as Pojo,plain old Java object Common, traditional Java objects), generally contains the required business logic method, Typically, the state of these object models is kept in a database to provide persistent support;

2, DAO (Database Access Object) layer: This layer consists of a series of DAO components, the completion of the database of CRUD (create, query retrieve, update updates, delete) and other operations;

3. Business Logic Layer: This layer consists of a series of business logic objects that implement the logical methods required by the system, which may be used only to expose the business logic method implemented by the domain object object, or it may be the business logic method implemented by DAO. In order to achieve;

4, the controller layer: the layer is mainly composed of controller components, the controller is used to intercept user requests, and forward the request to their respective business logic method, processing user requests, and forwarding the processing results to different presentation layer components;

5. Presentation layer: This layer consists of a series of view components, including JSP page, velocity page, etc., which collects the user request and displays the result to the user;

The Java EE components are loosely coupled, top to bottom, and the implementation of the upper component relies on the functionality of the lower component, and from the bottom up, the lower component provides support for the upper component.

Java EE Architecture