1.6.1

Simple 2

1/2

 Tier Application

HTTP/HTML/XML

Java method invocation (JDBC)

Browser

JSP

The simple 2 tier model (accessing a database in the example above) describes the cgi bin 

replacement architecture that the Servlet model first enabled. This allows a JSP (or a Servlet) 

to directly access some external resource (such as a database or legacy application) to service 

a client's request. The advantage of such a scheme is that it is simple to program, and allows 

the page author to easily generate dynamic content based upon the request and state of the 

resource(s). However this architecture does not scale for a large number of simultaneous 

clients since each must establish/or share (ad hoc) a (potentially scarce/expensive) 

connection to the resource(s) in question.

1.6.2

N tier Application

HTTP/HTML/XML

RMI/IIOP

Browser

JSP

EJB

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JavaServer Pages 1.1 Specification   November 30, 1999