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JSP versus ASP

JSP and ASP do have some basic concepts in common. They both make use of simple sever-side scripting to provide access to Web server information and functionality. They both do so using object oriented scripting. And they both started out with similar styles of delimiting this scripting from a page's content. In fact, Microsoft is replacing ASP with ASP+ (or the .NET architecture), which is even more like JSP than ASP in that its pages are compiled upon request and run in a "virtual machine" (which supports multiple languages and is written in C#).

Yet while ASP primarily supports two scripting languages -- JScript and VBScript -- JSP actually supports real Java code, not a new scripting language. The difference is that the Java code inside a JSP page is more script-like because it doesn't require Java class and package definitions. As you will see, the Java code inside JSP is added to methods of a Java Servlet that are generated the first time the JSP is requested. Of course, JScript, VBScript, and Java are all object oriented to some degree, or maybe to avoid getting into a political argument with those of you would dispute this claim I should refer to them as "Quasi-Object-Oriented." Whatever we choose to call them, we can at least agree that the scripting languages used by JSP and ASP are all provided with a set of pre-established objects by the Web server that they use to generate a dynamic Web page.

The following table lists some of the pre-established (instantiated, for the purist) objects that are available in both ASP and JSP.

Note that JSP is Java, so it is case sensitive. But capitalization doesn't matter in VBScript, so if you stick to lowercase, there really isn't any difference in the names.

These are the main objects we have to work with when creating dynamic content in either ASP or JSP, so it's a good idea to become familiar with their methods. I'll use some of them in the examples that follow, but I can't go into every method available within the limits of this article.

As I mentioned earlier, both ASP and JSP support a similar way of delimiting scripting from content on a page. <% and %> are used to set of sections of script, '<%=' and '%>' are used to return a value within content, and <%@ and %> are used to delimit page directives. Here is a brief example using both ASP and JSP:

<%@ LANGUAGE = JScript %>
<TITLE>Simple Scripting Tricks</TITLE>
Anyone can count like this:<BR>

<%
   for (i = 1; i < 6; i++) {
     Response.Write(i + "<BR>");
   }
   i = 1000000;
%>
It would take a long time, however, to count to <%= i %>.

<%@ page language="java" %>
<TITLE>Simple Scripting Tricks</TITLE>
Anyone can count like this:<BR>
<%
   for (int i = 1; i < 6; i++) {
     out.println(i + "<BR>");
   }
   i = 1000000;
%>

It would take a long time, however, to count to <%= i %>.

<TITLE>Simple Scripting Tricks</TITLE>
Anyone can count like this:<BR>

1<BR>
2<BR>
3<BR>
4<BR>
5<BR>
It would take a long time, however, to count to 1000000.

As you can see, there are some basic similarities between ASP and JSP. In fact, in this simple example, there's almost no difference. When we look deeper into JSP, however, fundamental differences will appear.