EJB & JSP: Java On The Edge, Unlimited Edition by Lou Marco ISBN: 0764548026 Your Guide to Cutting-Edge J2EE Programming Techniques. Chapter 1: Enterprise Computing Concepts JavaServer Pages (JSPs) and Enterprise JavaBeans (EJBs) are part of a server-side application development specification called the Java 2 Platform, Enterprise Edition (J2EE). Before you jump into the specifics of JSPs or EJBs, some background on enterprise application development, J2EE, and how JSP and EJB fit into J2EE is in order. This chapter sets the stage with information on the characteristics of a typical computing environment found in a modern corporation. Next, you read about two significant advancements in computer science that provide application developers with the means to satisfy their customers demands for computing services. You get a high-level look at J2EE and see how J2EE addresses the needs of application developers. You read about the components of J2EE, which include JSP and EJB. The chapter closes with a short discussion on the roles that JSPs and EJBs play in developing enterprise applications with the J2EE specification. The Enterprise Computing Environment Today s corporate computing environment is a different animal from its ancestors. Typically, enterprise computing environments are: . Data-Obsessed: These days, the modern company is addicted to its data. With storage costs low, companies are less likely to purge data stores today than in years past. Some industries, such as brokerage and insurance, keep decades worth of data and subject their data to intense analysis. The astute corporate mavens realize that corporate data is an asset worth exploiting. Those in charge look to their computing professionals to provide tools that exploit this valuable asset. . Distributed: Today s enterprise computing environment has grown beyond the scenario of a single machine in an air-conditioned room, with rows and rows of storage devices, serving hundreds or thousands of dumb green screens. The more likely scenario for today s environment is one of networked servers in diverse geographical locations that serve data to hundreds or thousands of comparatively smart GUI clients. . Secure: A good deal of corporate data must be kept from the prying eyes of the pesky, prying employee itching to know who got the biggest raise in the department, the dementedly disgruntled employee looking to vend proprietary information, and the capriciously curious employee trying to learn about various systems and applications. . Scalable: The environment that serves the needs of one hundred may be inadequate to serve the needs of one thousand. As the number of users increases, resources, such as bandwidth or database connections, have a bad habit of thinning out to unacceptable levels or simply running out. . Fault tolerant: With the computing environment distributed among many parts, the possibility of any single part failing increases with the number of parts. The company cannot afford to have its systems crash and burn every time a server winks out or a data store goes offline. . Heterogeneous: The days of a company using products from a single vendor are gone. More likely, a company uses a mix of hardware and software from several competing vendors. Today, everything from the physical disk
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