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<big>J</big>AVA<big>S</big>ERVER <big>P</big>AGES<SUP>
<small>TM</small></SUP><BR>A Simplified Guide
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<b class="heading">4. JSP Technology in the Multitiered Architecture</b></td>
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<P>JSP technology can be used to create simple, interactive pages that report the time
of day or track visit-counts to a page. But this technology also scales well to takes
its place in an enterprise-level, multitier application architecture.<br>
Pages created with JSP technology are the server-based, "customer-facing" interface
for multitier applications, and provide a flexible, scalable environment for deploying
these applications.</P>
<P><B>Client Tier</B></P>
<P>On the client side, JSP pages communicate with Web-based clients, including HTML-based
browsers. The page manages the browser interaction, sending and receiving requests and
information, typically in HTML format.</P>
<P><B>Middle Tier</B></P>
<P>JSP pages may reside in almost any Web server or application server. The pages have
access to the wide range of Java APIs and services, including
JDBC<SUP><small>TM</small></SUP> technology for database access,
JavaMail<SUP><samll>TM</small></SUP> software for Java technology-based e-mail
applications, Java Transaction API for transaction services, and so on.</P>
<P><B>Data/EIS Tier</B></P>
<P>Enterprise JavaBeans<SUP><small>TM</small></SUP> components in the middle tier
can manage access to enterprise resources in the data/EIS tier, handling security,
authorization, transaction integrity, connection pooling, and data caching.
Enterprise JavaBeans and their containers encapsulate the complex logic required for
high-performance, highly secure enterprise applications.</P>
<P><B>Flexibility and Adaptability</B></P>
<P>The beauty of the JSP architecture is its flexible, adaptable design. The
back-end data sources are independent from the application logic, which itself is
independent from the browser presentation.</P>
<P>For example, it is easy to add new JDBC technology-compliant data sources to
an existing application infrastructure. Likewise, new Web-based applications can be
built that access existing resources, without reworking the original data sources.
Logic that is built once and encapsulated in beans or Enterprise JavaBeans components
can be leveraged for many different applications. And the rich and evolving family
of Java APIs means that there are continually expanding options for application
integration.</P>
<P><B>The Competitive Landscape</B></P>
<P>JSP technology is not the first approach for enabling interactive Web pages -
rather, it is the next step in the progression of products supporting Web-based
clients.</P>
<P>Some of the earlier methods include CGI programs, the mod_perl plug-in for
the Apache Web Server, and Microsoft Active Server Pages (ASP). For further
discussion of these technologies and their differences from JSP technology,
please go to java.sun.com/products/jsp/.</P>
<P>The JSP technology surpasses these previous methods in two fundamental areas:
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<LI>Portability - Pages built with JSP technology are portable across platforms
and servers, and work with portable, reusable components.</LI>
<LI>Easier Maintenance and Development - Because the page design is truly
separate from the application logic, JSP enables tiered development and
maintenance tasks, so page authors and developers can focus on specific
areas of interest without requiring the others' help.</LI>
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<b class="heading">5. Summary</b></td>
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<P><B>JSP Technology Powers Dynamic Content on the Web</B></P>
<P>JSP technology builds on the strength of the Java family and the multivendor
Java community, extending the core capabilities of the Java platform to create
powerful, flexible, and easy-to-maintain dynamic Web pages. JSP technology
inherits all of the benefits of the Java language, including platform- and
server-independence, a modular and reusable component architecture, and access
to the rich family of Java APIs (including JDBC, JavaMail, and Java Transaction
Service).</P>
<P>Using JSP technology, organizations can meet their users' needs for up-to-date,
high-performance, and reliable Web-based applications, while addressing the overall
organizational needs for long-term architectural decisions:
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<LI>Vendor Independence - Many different Web and application servers support
JSP technology, and more are added every day. The JSP specification
is the product of the Java Community Process (JCP), an open process
used by Sun since 1995 to develop and revise Java technology and
specifications in cooperation with the international Java community.
The result is a specification, built with the input and support of
the major vendors in the market, that does not lock companies into
any one vendor's solutions.</LI>
<LI>Portability - JSP technology is portable across platforms and servers
alike, building on the Write Once, Run Anywhere philosophy of the
Java language. Not only are the pages themselves portable, but they
can access Java technology-based components (beans, customized JSP tags)
that are also reusable and portable across platforms.</LI>
<LI>Flexibility - The multitier architecture using JSP technology is inherently
flexible and adaptable. Developers can change data sources, access
external data if necessary, and implement new security or authorization
methodology - all without affecting "customer-facing" applications.
Similarly, new applications can be built without reworking the
infrastructure to support them. This enables organizations to adopt new
technologies or applications as their business needs change.</LI>
<LI>Low Cost of Ownership - JSP technology lets page authors handle the ongoing
maintenance of dynamic pages without requiring developers to be involved
in changes that do not involve application logic. Likewise, JSP custom
tag libraries make it easy for developers to distribute advanced
application functionality to a wide variety of page authors. And, as
part of the Java family, JSP technology enables businesses to
leverage Java language expertise, JavaBeans components, and existing
Java technology-compatible components or data sources.</LI>
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<center><pre class="textbody">
Web Page Designed By : <i><a href="mailto:chengchien@linkline.com">Cheng-chien Yu</a></i>
Attaendant Class : Santa Monica College - CIS 36H
Due Date : September 29, 2001.
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