Web Applications

Many of today's enterprise applications implement a web frontend. They choose to expose their business functions via a web user interface, most often accessed from the client's browser. These applications may access other enterprise services such as XML transformers, JNDI, database resources, and connection factories to fulfill their service contracts. WebLogic Server provides the ideal environment for creating rich web applications it offers an extensive range of tools for assembling and configuring web components. Like any servlet engine, WebLogic supports all the functionality needed to host multiple web applications, which we shall cover in detail in later chapters.

In this chapter, we look at the internal structure of web applications and their associated XML deployment descriptors. We shall see how WebLogic eases the task of building and assembling web applications, and examine some of the deployment issues of WebLogic Server. We also look at how you can configure the various web components.

We take a peek at WebLogic's JSP compiler, and then examine JSP configuration issues when deploying a web application. Custom JSP tags are a useful mechanism for adding dynamic content to a JSP page. WebLogic provides a number of tag libraries. One such tag library offers useful caching functionality. Similar caching functionality is made available in the form of a servlet filter. WebLogic also provides a tool that can automatically create a JSP tag library from EJB components.

You also will learn about WebLogic's servlet support, such as session tracking and session persistence. WebLogic provides a number of ways to persist session state. File-, memory-, and cookie-based persistence mechanisms are supported. When using servlets in a cluster, in-memory session replication also can be used. This chapter examines these mechanisms, and looks at how to set up a simple web cluster with session replication.

Finally, we look at various ways in which you can secure a web application using declarative and programmatic techniques. Setting up the HTTP over SSL (HTTPS) listen port and the associated SSL configuration is covered in Chapter 16. Chapter 3 concludes the discussion of the web environment it describes how you can use and configure WebLogic's HTTP server and proxy plug-ins.