The JavaTM Web Services Tutorial

Web Applications

Stephanie Bodoff

A Web application is a dynamic extension of a Web server. There are two types of Web applications:

In the Java 2 Platform, Web components provide the dynamic extension capabilities for a Web server. Web components are either Java Servlets or JSP pages. Servlets are Java programming language classes that dynamically process requests and construct responses. JSP pages are text-based documents that execute as servlets but allow a more natural approach to creating static content. Although servlets and JSP pages can be used interchangeably, each has its own strengths. Servlets are best suited to service-oriented Web applications and managing the control functions of a presentation-oriented application, such as dispatching requests and handling nontextual data. JSP pages are more appropriate for generating text-based markup such as HTML, SVG, WML, and XML.

Web components are supported by the services of a runtime platform called a Web container. In the Java Web Services Developer Pack (Java WSDP) Web components run in the Tomcat Web container. The Web container provides services such as request dispatching, security, concurrency, and life cycle management. It also gives Web components access to APIs such as naming, transactions, and e-mail.

This chapter describes the organization, configuration, and installation and deployment procedures for Web applications. Chapters 10 and 9 cover how to develop Web components for service-oriented Web applications. Chapters 12 and 13 cover how to develop the Web components for presentation-oriented Web applications. Many features of JSP technology are determined by Java Servlet technology, so you should familiarize yourself with that material even if you do not intend to write servlets.

Most Web applications use the HTTP protocol, and support for HTTP is a major aspect of Web components. For a brief summary of HTTP protocol features see HTTP Overview.

In This Chapter
Web Application Life Cycle
Web Application Archives
WAR Directory Structure
Tutorial Example Directory Structure
Creating a WAR
Configuring Web Applications
Alias Paths
Context and Initialization Parameters
Event Listeners
Filter Mappings
Error Mappings
References to Environment Entries, Resource Environment Entries, or Resources
Installing Web Applications
Deploying Web Applications
Listing Installed and Deployed Web Applications
Running Web Applications
Updating Web Applications
Reloading Web Applications
Redeploying Web Applications
Removing Web Applications
Undeploying Web Applications
Internationalizing and Localizing Web Applications
Accessing Databases from Web Applications
The Examples
Installing and Starting the Database Server
Populating the Database
Configuring the Web Application to Reference a Data Source
Defining a Data Source in Tomcat
Configuring Tomcat to Map the JNDI Name to a Data Source
Further Information

This tutorial contains information on the 1.0 version of the Java Web Services Developer Pack.

All of the material in The Java Web Services Tutorial is copyright-protected and may not be published in other works without express written permission from Sun Microsystems.