iTP Secure WebServer System Administrator's Guide (iTPWebSvr 5.1+)

Using NonStop Servlets for JavaServer Pages With
The iTP Secure WebServer
iTP Secure WebServer System Administrator’s Guide—522659-001
9-7
JavaServer Pages
•
Deploy and Create (web archive) WAR files
JavaServer Pages
JavaServer Pages, a presentation layer technology that sits on top of the Java servlets
model, is used to simplify the creation and management of dynamic HTML. The
technology takes a component-based rather than page-based approach to development.
With page-based design the web page combines the presentation material usually
created by designers with the business logic usually created by programmers.
By separating the user interface from content generation JSP allows page designers to
change the page layout without altering the underlying programmable dynamic content.
Furthermore the programmable content, or business logic, can be written in the form of
reusable components such as Java Beans. This separation of the page logic from its
display and the support for a reusable component-based design makes JSP a faster and
easier way to build web-based applications.
JavaServer Pages uses XML-like tags and scriptlets written in the Java programming
language to encapsulate the logic that generates the content for the page. Additionally,
the application logic can reside in server-based resources Java Beans that the page
accesses with these tags and scriptlets. All formatting (HTML or XML) tags are passed
directly back to the response page. The underlying JSP engine (actually a specialized
servlet itself) transforms JSP tags, scriptlets and HTML into Java code which is
organized as a Java servlet. In JSP 1.1 the servlet is precompiled as Java bytecode, thus
the page does not need to be interpreted every time it is requested. The code is
recompiled automatically if the page is changed.
A high level view of JSP is shown in Figure 9-2, JSP Data Flows
.
Figure 9-1. A J2EE Web Container With Two Applications
VST901.vsd
WEB CONT A INER
APPLICATION # 2
JAVA
SERVLETS
DEPLOYMENT
DESCRIPTOR
JAVA
CLASSES
JSP
PAGES
APPLICATION # 1
JAVA
SERVLETS
DEPLOYMENT
DESCRIPTOR
JAVA
CLASSES
JSP
PAGES