There is something to be said for the sharing of knowledge. While this isn’t a massive world-wide project like the first dictionary or encyclopedia, I’d like to think it will have a use, in spite of me. This article series is about the sharing of knowledge, and has been called “The Encyclopedia of Web Technologies.”

I only wish I could be quite that exhaustive; however, since I’ve already written more than 100 pages of text, I figure, why stop now? This time around, we continue to look at Server-Side Scripting languages which, without sounding glib, allow you to add some form of basic intelligence to your website.

We continue to explore technologies which enable you to make HTML, CSS and JS dynamically and in an automated manner. There are many sites — from Ebay.com to your local search engine — which use Server-Side Programming to automatically create the pages you asked for, exactly the way you asked for them. Each of the technologies in both our last article and this one can really do “anything;” it is really up to the programmer to measure the advantages and disadvantages in relation to the current project.

Let’s move on then, shall we?

JSP Definition

JSP is a Sun Microsystems technology. You know Sun; it’s the company behind Java. It’s a good company, and JSP expands on an already good technology. JSP is a free specification for extending Java Servlets to generate dynamic web pages on a web server.

Like most of our other technologies, JSP lets developers create dynamic HTML or XML pages that combine static page elements with dynamic content. This allows smart developers to separate user bits like HTML from logic bits, such as the JSP code. JSP was created to simplify the Java Servlets technology (which we’ll cover in a future article) and to be less complicated than other offerings, CGI being one example, available at the time of its creation.

What It Really Is

So we understand that JSP is an extension of Java for web pages, but what is it really about? For most people, Java’s biggest appeal is that it can tie into existing Java elements, and therefore save a lot of development time.

JSP is based on components. It uses JavaBeans and Enterprise JavaBeans (EJB) components which hold the business logic for an application. JSP composes tags and a scripting platform for presenting the content generated and returned by the beans into HTML pages. The components structure means that non-Java developers can use JSP to manipulate beans built by Java developers. On the other hand, Java developers can use these beans and Java in JSP pages for more advanced productions based on the beans.

What is really happening in this process? A user calls a JSP page through their browser. Then Resin (for instance) located on the web server converts JavaScript, JSP tags, and HTML into segments of Java code, which the engine consequently arranges into a core Java servlet. This core servlet is, therefore, pre-assembled and works “behind the scenes.” It is called every time that particular page is requested by a user, saving valuable recompiling time. The next time a user calls that page from their browser, the JSP code has already been compiled, and it does not have to convert the JavaScript, HTML, etc. each time. That is, the servlet engine needs only to produce that servlet once, or after the last code change was implemented.

JSP uses a combination of XML and CFM-like tags, as well as scripts written in Java, to generate page content. Applications written to the JSP specification can be run on compliant web servers, and web servers such as Apache, Netscape Enterprise Server, and Microsoft IIS that have had Java support added.

Advantages

+ Strong integration with JavaBeans and other elements
+ Ease of use for experienced Java developers
+ Rapid Application Development
+ Adept scaling to heavy loads
+ Cross-platform compatibility
+ Open Source availability

Disadvantages

+ Slower speed due to being more robust and intensive (JSP pages often run slower than
similar pages using technologies such as PHP, for example)
+ Steeper learning curve when compared to many other technologies

Examples

For a multitude of examples of PHP usage, as well as a full manual, go to php.net/manual. Following are some standard types of things you might find.

Similar Technologies

In reality, any Net-based scripting language is somewhat similar to JSP in that it fulfills the same goals, and we will look at most of these in future articles within this series:

+ ColdFusion: ColdFusion is Macromedia’s offering for web-based dynamic content. While technically, it isn’t “scripting,” as it is based on an HTML-like tag structure, it still fulfills the same goal of providing dynamic webpages.

+ PHP: Just like JSP, PHP is cross-platform compatible. In some ways, it is simpler to develop, because it doesn’t require separate files for logic and procedures. It is also is harder to work with for basically the same reason. PHP is a very strong language with an incredibly large and supportive community