Programming Jakarta Struts, Second Edition

Chapter 2. Inside the Web Tier

This chapter discusses the relationship between the architectural tiers and their roles in an application. Special attention is given to the web tier, which allows an application to communicate and interoperate with clients over the Web. In particular, this chapter focuses on the physical and logical aspects of designing and using a web tier for your applications.

The Struts framework is based on the Java Servlet technology and, to a lesser extent, JavaServer Pages, and therefore is dependent on a web container. For Struts developers, understanding how the web container processes client requests is fundamental to a deeper understanding of the framework itself. This chapter illustrates the various components that are part of the web container and discusses each component’s responsibilities.

An Architecture Overview

This section presents a high-level architectural view of a Struts application. Although this section shows an architecture for an enterprise application, not all applications written using Struts will be of this size and makeup. However, this type of application does allow us to present many facets of how Struts applications may be configured.

Many applications—especially J2EE applications—can be described in terms of their tiers. The application’s functionality is separated across these tiers, or functional layers, to provide separation of responsibility, reusability, improved scalability, and many other benefits. The separation of tiers ...