Components of web-based applications
All web-based database applications have three primary components: A web browser (or client), a web application server, and a database server.
Web-based database applications rely on a database server, which provides the data for the application. The database server sometimes also provides business logic in the form of stored procedures. Stored procedures can offer significant performance advantages, especially in a multi-tiered architecture. In addition to database servers, other enterprise information system components include IMS databases, IBM MQ messages, and CICS® records.
The clients handle the presentation logic, which controls the way in which users interact with the application. In some cases, the client validates user-provided input. Web applications sometimes integrate Java™ applets into the client-side logic to improve the presentation layer.
- Applet
- A Java program that is part of a Hypertext Markup Language (HTML) page. (HTML is the standard method for presenting web data to users.) Applets work with Java-enabled browsers, such as Microsoft Internet Explorer; they are loaded when the HTML page is processed.
Web application servers manage the business logic. The business logic, typically written in Java, supports multitiered applications. The web application server can manage requests from a variety of remote clients. The web application layer might include JavaServer Pages (JSP) files, Java servlets, Enterprise JavaBeans (EJB) components, or web services.
- JSP
- A technology that provides a consistent way to extend web server functionality and create dynamic web content. The web applications that you develop with JSP technology are server and platform independent.
- Servlet
- A Java program that responds to client requests and generates responses dynamically.
- EJB
- A component architecture for building distributed applications with the Java programming model. Server transactional components are reusable and provide portability across application servers.
- Web services
- Self-contained, modular applications that provide an interface between the provider and the consumer of application resources. You can read more about web services later in this information.