Servlets JavaServer Pages Web Application Modules

Overview of WebLogic Server Application Development 1-3

1.3 Overview of Java EE Applications and Modules

A WebLogic Server Java EE application consists of one of the following modules or applications running on WebLogic Server: ■ Web application modules—HTML pages, servlets, JavaServer Pages, and related files. See Section 1.4, Web Application Modules . ■ Enterprise Java Beans EJB modules—entity beans, session beans, and message-driven beans. See Section 1.5, Enterprise JavaBean Modules . ■ Connector modules—resource adapters. See Section 1.6, Connector Modules . ■ Enterprise applications—Web application modules, EJB modules, resource adapters and Web Services packaged into an application. See Section 1.7, Enterprise Applications . ■ Web Services—See Section 1.8, WebLogic Web Services . A WebLogic application can also include the following WebLogic-specific modules: ■ JDBC and JMS modules—See Section 1.9, JMS and JDBC Modules . ■ WebLogic Diagnostic FrameWork WLDF modules—See Section 1.10, WebLogic Diagnostic Framework Modules .

1.4 Web Application Modules

A Web application on WebLogic Server includes the following files: ■ At least one servlet or JSP, along with any helper classes. ■ Optionally, a web.xml deployment descriptor, a Java EE standard XML document that describes the contents of a WAR file. ■ Optionally, a weblogic.xml deployment descriptor, an XML document containing WebLogic Server-specific elements for Web applications. ■ A Web application can also include HTML and XML pages with supporting files such as images and multimedia files.

1.4.1 Servlets

Servlets are Java classes that execute in WebLogic Server, accept a request from a client, process it, and optionally return a response to the client. An HttpServlet is most often used to generate dynamic Web pages in response to Web browser requests.

1.4.2 JavaServer Pages

JavaServer Pages JSPs are Web pages coded with an extended HTML that makes it possible to embed Java code in a Web page. JSPs can call custom Java classes, known as tag libraries, using HTML-like tags. The appc compiler compiles JSPs and translates them into servlets. WebLogic Server automatically compiles JSPs if the servlet class file is not present or is older than the JSP source file. See Section 4.2, Building Modules and Applications Using wlappc . You can also precompile JSPs and package the servlet class in a Web application WAR file to avoid compiling in the server. Servlets and JSPs may require additional helper classes that must also be deployed with the Web application. 1-4 Developing Applications for Oracle WebLogic Server

1.4.3 More Information on Web Application Modules