Application of two kinds of design patterns in EJB development

Absrtact: This paper introduces the layered structure of Java EE, and deeply studies how to design EJB with session façade pattern and valueobject pattern, and explains the development process in detail.

Keywords: EJB; value object mode; session appearance mode

I. Overview

Compared with the traditional two-tier architecture, Java EE has two features:

1. Defines a set of standardized components that provide a complete service for these components.

2. Use a multi-tier distributed Application model. The logic of an application is encapsulated in different components according to the different functions it implements. As shown in Figure 1.

This multi-tier architecture enables enterprise-class applications to be highly scalable, allowing each tier to focus on a particular role:

1, Client tier for display.

2. Web tier for generating dynamic display.

3, Business tier is used to implement business logic.

4, EIS tier for database services.

The EJB component architecture, which is used to implement business logic, is the foundation and most important part of Java EE.

It is recognized that the Java-EE platform, as an extensible, full-featured platform, can extend key enterprise applications to any Web browser and can be adapted to a variety of different internet streams, accessible to virtually any traditional database and solution, Java EE has become the development of e-commerce application of the fact standard.

To enable developers to develop standardized, reusable applications, Java EE provides us with a large number of patterns. Patterns, though sometimes difficult to understand, are very simple to use, providing a powerful reusable mechanism that avoids the duplication of investment by developers and designers.

However, in the face of so many patterns, beginners often do not know how to do so, the author combined with the previous development experience, detailed description of how to use the model to complete the EJB design.