Chapter 4: Deploying Web Applications

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Overview

The previous chapters have covered the fundamental topics relating to the use of servlets in the enterprise, and those relating to the latest incarnation of the Servlet API, version 2.3. This chapter continues this look at the fundamentals by discussing servlet deployment.

With servlets, and more generally J2EE, the design and development process is very clearly isolated from the processes of application packaging and deployment. With servlets we are encouraged to develop loosely coupled components that are reusable. The components are then tied together into an application at packaging and deployment time. This allows the programmer to concentrate on what they do best during development, the process of coding business logic, leaving infrastructure issues (such as security, database connection pooling, and transactions) until the deployment stage.

As the title suggests this chapter focuses on this servlet packaging and deployment process. We will look at facilities provided by servlet-compliant web containers, which will allow us to develop flexible applications. The specific issues that we will address are:

• Web applications and their structures

• Development versus production deployment

• The web application deployment descriptor XML file

• Validating deployment descriptors

• Building web application archive files by hand

• An example of a complete web application

• Some advanced deployment issues

Let's start by defining what a web application is in the context of J2EE.

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