Choosing a server-side language used to be easy. Way back when,
CGI was pretty much
the only scripting option out there. Intrepid developers could
write their own server extensions, but few were up to the
challenge, and the gap between these two options (inefficient CGI
scripts and extremely complex server extension development) was
huge.
Microsoft tried to fill this hole with Active Server Pages (ASP),
which allow developers to use simple scripting to access the server
and its extensions. But while ASP gives you an efficient way to
return dynamic content, it essentially limits you to Microsoft platforms, and
even the simplest of scripting mistakes can cause the server to
crash or hang, effectively bringing down your website.
Apparently in response to ASP, Sun Microsystems gave the world
JavaServer Pages (JSP) technology, which is based entirely upon
Sun's popular Java
programming language and gives developers the advantages of
developing in Java in a more relaxed, script-like environment.
Behind the scenes, JSP pages are dynamically assembled into Servlets, which are simply
Java classes. This means JSP supports the same modularity,
reusability, platform-independence, and access to Java APIs that
Java programming supports.
Thanks to its foundation in Java and its use of Java threads to
handle incoming requests, JSP is a great deal more efficient than
many other scripting languages, such as CGI. Its threading model
and error handling also help prevent server hangs and crashes. And
when the underlying Java Virtual Machine (JVM) makes use of Just In
Time (JIT) compilation, the performance of well-written JSP can
approach that of C++.
JSP also bests ASP by supporting the definition of tags that
abstract functionality within a page, so tags can be defined in a
tag library and then used within any JSP page. This makes for a
better separation of page content from its code, which is one of
Web development's prime directives. The less code scattered
throughout the pages of a website, the easier the site is to
maintain. Global changes need only be made to the tags defined in a
central library, making time-consuming, page-by-page fixes things
of the past.
For those XML lovers
among us, good news: JSP pages can be written in well-formed,
valid XML by using XSLT. (For those of you
who aren't XML-spawn, this simply means that JSP can make full use
of a very powerful and widely accepted data format and all the
tools and support that go with it.)
And unlike ASP, JSP is a lot less platform-specific and it
doesn't rely as heavily on the company that created it for support
or performance improvements. That said, there are some similarities
between JSP and ASP. Here, let's closer look at how the two
compare.
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