JSP Technology -- Friend or Foe?

By Brett McLaughlin
2003-03-07

Code vs. markup

Second on the JSP technology's list of features is something that might raise a bit of concern. JSP coding lets you insert Java code directly into a page of markup. To understand why this decision was made, recall that when the JSP specification was being developed, Sun's competition from Microsoft was at an all-time high, primarily due to the success of Microsoft Active Server Pages (ASP). The similarity of the name JavaServer Pages to Active Server Pages was not merely coincidental. And the ability to mimic many of ASP's features was also intentional. So JSP authors were given the option to add Java code into their markup.

As an example of Java code being added to markup, the JSP snippet in Listing 4 dynamically adds rows as needed to show each item in the Vector of actors.

<%@ page import="com.ibm.display.PageUtils" %>

<%@ page import="com.ibm.display.PageInfo" %>

<%@ page import="com.ibm.people.Actor" %>

<%@ page import="java.util.Iterator" %>

<%@ page import="java.util.Vector" %>

<%

PageInfo pageInfo = (PageInfo)session.getAttribute("PAGE_DATA")

Vector actors = pageInfo.getActors()

%>

<HTML>

<HEAD>

 <TITLE>

  <%=pageInfo.getTitle()%>

 </TITLE>

</HEAD>

<BODY>

 <H2 ALIGN="center">Search Results: Actors</H2>

 <CENTER>

  <HR width="85%">   

  <TABLE width="50%" CELLPADDING="3" CELLSPACING="3" border="1"

         BGCOLOR="#FFFFCC">

<%

 for (Iterator i = actors.iterator(); i.hasNext()) {

  Actor actor = (Actor)i.next();

%>

    <TR BGCOLOR="#FFCCCC">

      <TH width="50%" ALIGN="center">

       <%=actor.getLastName()%>

      </TH>

      <TH width="50%" ALIGN="center">

       <%=actor.getFirstName()%>

      </TH>

    </TR>

<%

 }

%>

  </TABLE>

 </CENTER>

</BODY>

</HTML>

Remember that so far I am simply describing the initial design goals of JSP technology; I'll defer my own judgment about the goals until a later section about the problems of JSP technology. You might be a little suspicious already, however, since embedding code into a JSP page would seem to cause problems with the first goal of JSP technology, separating content from presentation. But really (ahem), I'm not editorializing yet.

Tutorial Pages:
» A critical look at JavaServer Pages servlets as a viable presentation technology
» A bit of history
» The premise
» Segregation vs. integration
» Work vs. rework
» The promise of JSP technology
» Content vs. presentation
» Code vs. markup
» Designer vs. developer
» The problems
» Portability vs. language lock-in
» Mingling vs. independence
» Blurring the line between content and presentation
» Single-processing vs. multi-tasking
» HTML vs. XML
» Summary
» Resources

First published by IBM developerWorks

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