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Transcript
Java Server Pages (JSP)
Presented by:
Ananth Prasad & Alex Ivanov
May 10, 2001
JSP Definition
JSP is a dynamic scripting capability for web
pages that allows java as well as a few
special tags to be embedded into a web file
(HTML/XML, etc). The suffix traditionally
ends with .Jsp to indicate to the web server
that the file is a JSP file. JSP is a server side
technology - can't do any client side
validation with it
JSP
JSP
• A JSP file is a script like an ASP file except
that represents a template for a web page.
• When the page is first requested, the JSP is
compiled into a “servlet” form and
executed.
• Afterwards the JSP script exists as a
compiled java byte-code (unless it is
changed)
Why not just write Servlets?
The focus is on HTML. Java and the JSP
extensions assist in making the HTML more
functional. Servlets on the other hand allow
outputting of HTML but it is a tedious
process.
It is easy to make a change and then let the JSP
capability of the Web Server you are
using deal with compiling it into a Servlet and
running it.
JSP
JSP Benefits
Easy and Rapid Web Development,
Deployment and Maintenance
Emphasizing Reusable Components
Separating Content Generation from
Presentation
JSP Benefits Contd.....
Open Development and Widespread
Industry Support
Platform Independence
Simplifying Page Development with
Tags
Use of Beans
One use of JavaBeans is as a data
encapsulator. A property of a JavaBean is
simply the data (state) of the bean.
Properties are accessible by two methods:
the getter and the setter. The value of the
property is accessed by the getter method. If
the property is writeable, its value is
changed by the setter method.
Use of Beans contd.....
Loading a Bean - <jsp:usebean>
Initializing a Bean - <jsp:setProperty>
Displaying Dynamic Content <jsp:getProperty>
Java code in your page?
Three ways…
• Using declarations, <%!.........%>.
• With scriptlets,
<%...........%>.
• Expressions between <%=.....%>.
A look at simple JSP code
<html>
<body>
<b>I’m HTML code.</b><br>
<% out.println(“I’m Java code.”) %>
</body>
</html>
Example, “Hello, World”
Example:
<%
String name = null;
if (request.getParameter(“name”) == null ) {
%>
Hello, World
<% } else {
println.out(“Hello,” + name); }
%>
JSP Vs JavaScript
JavaScript
–
–
–
–
–
Validates on Client Side
Less Secure
Browser Dependent
Unstable
….
JSP Vs. Servlets
Similarities
• Provide identical results to the end user
• JSP is an additional module to the servlet
JSP Vs Servlets
contd.....
Differences
• Servlets: “HTML in Java Code”
HTML code inaccessible to Graphics designer
But accessible to Programmer
• JSP: “Java Code Scriplets in HTML”
HTML code accessible to Graphic Designer
Java code accessible to Programmer
JSP Vs ASP
Web Server
Platforms
Reusable cross
platform
components?
Security against
System Checks
Customizable
Tags
ASP
IIS, PWS
Windows
No
JSP
Any
Any
Yes
No
Yes
No
Yes
Useful Links of JSP
• The current version of JSP is 1.1. It is available from
http://java.sun.com/products/jsp.
• Archives of the JSP mailing list are available at
http://archives.java.sun.com/archives/jsp-interest.html
• web application servers support JSP
http://www.flashline.com/components/appservermatrix.jsp
• JSP Demo website
http://www.flashline.com/
Conclusion
• JSP is robust server side dynamic web page
generator.
• Easy to implement
• Easy to manage
• Code is portable
• Free
References
• Web page development using JSP
by Duane K. Fields, Mark A. Kolb
• Java Server Pages -- by Hans
Bergsten
• Core Servlets and JSP -- by Marty
Hall
• Graphics used on this presentation was
obtained from different web sites.
The End
