Day 7. Designing Web Applications

Web applications consist of Web components that are responsible for processing Web client requests, invoking the business logic tier, and delivering data in response to client requests. Web components can be servlets, JavaServer Pages (JSPs), JavaBeans, or JSP tag libraries (taglibs). Web applications are packaged and deployed into the Web container using WAR (Web Archive) files. The Web tier handles all communications between Web clients (browsers) and business logic components in the EJB tier. The MVC (Model-View-Controller) architecture pattern is used mainly to design Web applications. The Web tier typically produces HTML (or XML) content in response to the client request, whereas business logic is often implemented as EJB components in the EJB tier, although it may also be implemented entirely within the Web tier using Web components.

In learning about the Web container and the Web components today, you'll

• Learn about Web applications, the Web container and its common services

• Learn about Java servlets as server-side components to process client requests

• Explore the JavaServer Pages technology to generate dynamic contents

• Learn how to develop a simple JSP tag library to hide application logic from its presentation

• Study the MVC architecture pattern that can be applied to the design of scalable Web applications

• Learn how to package and deploy a Web application using the Web tier deployment descriptor