Bitter servlets - Bitter Java - page 75

Command

JSP

Servlet

Client
HTML

Figure 3.6 The completed Triangle design pattern. This is a modified form of Model-View-
Controller. Because this technology is batch oriented, we have two views. The Client HTML is
the input view, and the JSP is the output view.

existing HTML tags. The JSP is then compiled and executed on the server. The
output of the executed JSP is a page of HTML . This HTML page is then
returned to the client.
This architecture offers many advantages:
JSP s allow dynamic content. Since HTML scripts like JavaScript execute on
the client, dynamic content that exists on the server is not available. Since
the JSP is compiled and run on the server, it is not limited like JavaScript.
Separation of concerns. JSP s can be created and maintained in an editor.
Many editors explicitly accept JSP tags and extensions. Almost all HTML
editors allow HTML tags to be passed through. Using this design, a
graphics designer can be deployed to build web pages even if dynamic
content is involved with a minimum amount of scripting.
JSP s can be used to isolate the view from the controller and the model. This
advantage is academic, but since it applies to one of the oldest and most
studied design pattern in modern history, it cannot be ignored. Years of
practical experience have shown that the Model-View-Controller design
pattern has improved readability, increased reliability, and reduced the
disadvantages of change.
JSP s are an open standard. Unlike many techniques for creating dynamic
content, JSP s are based on collaborative standards. All of the techniques
in this topic are compatible with JSP designs. JSP s permit connection
pooling, are compiled to long-running servlets, and handle dynamic
content without the need of a full applet on the client.