# JSPWeaver removes the first-person penalty from JSP development

| by Charles Humble 161 Followers on Feb 05, 2008. Estimated reading time: 1 minute |
ZeroTurnaround's JSPWeaver is a real-time interpreter for JSP which aims to remove the first-person penalty encountered when the server creates and compiles the background servlet from the JSP mark-up.

Configuring the product is straightforward. You put the jspweaver.jar into your web application's \WEB-INF\lib, and add some basic configuration information to the application's web.xml file to tell it to use the interpreter for *.jsp URLs:


<servlet> 	<servlet-name>weaverServlet</servlet-name>	<servlet-class>com.zeroturnaround.jspweaver.JspInterpretingServlet</servlet-class>	<load-on-startup>1</load-on-startup></servlet><servlet-mapping> 	<servlet-name>weaverServlet</servlet-name>	<url-pattern>*.jsp</url-pattern></servlet-mapping>

Once the application server is re-started JSP pages will be interpreted on the fly.

The interpreter currently supports JSP 1.2-2.0. The 1.0 release supports the full JSP standard including common syntax, XML syntax and Java scriplets. It is container agnostic and should work with any JSP compliant container although the currently tested containers are:

• BEA Weblogic 8.1SPX, 9.X
• Jakarta Tomcat 4.X, 5.X, 6.X
• JBoss 4.X
• Jetty 5.X
• Oracle Application Server 9.X, 10.X

Support for JSP 2.1 is planned for the next release and Jevgeni Kabanov at ZeroTurnaround told InfoQ he expects it to be available in about a month. He also gave us a few more details on how the product works:

"It pretty much parses the JSP (either XML-style or original syntax, two separate parsers) and creates an in-memory representation of the pages, which can be used to render the actual output. Since the parsing is very quick and there is no translation it is much faster than compilation can ever be. We also use a patched version of BeanShell to interpret the embedded Java scriplets."

A free trial version is available from ZeroTurnaround. A license costs \$49/seat.

Style

## Hello stranger!

You need to Register an InfoQ account or or login to post comments. But there's so much more behind being registered.

## Get the most out of the InfoQ experience.

### Tell us what you think

Allowed html: a,b,br,blockquote,i,li,pre,u,ul,p

Email me replies to any of my messages in this thread

How well does it deal with scriptlets?

Disclaimer: I wrote what is effectively a competing project, but I don't make any money from it, and I don't have a huge amount of attachment to it

Parsing scriptlets in an interpreter is hard.
You have conditionals that cross scriptlets, and it's incredibly difficult to support those without converting the whole thing into Java.
Does JSPWeaver really do it, or does it just do a "good enough" job (which is all slim does too)

Side note: Strictly speaking, JSPWeaver cannot be a standard compliant JSP implementation (not that it claims to be) as the JSP spec requires that pages be converted into servlets. (Uck!)

Re: How well does it deal with scriptlets?

Re: How well does it deal with scriptlets?

Parsing scriptlets in an interpreter is hard.
You have conditionals that cross scriptlets, and it's incredibly difficult to support those without converting the whole thing into Java.
Does JSPWeaver really do it, or does it just do a "good enough" job (which is all slim does too)

Yep, it's hard, and yes we do that.

Somehow every time I post here formatting ends up messed up :(

Great Job

Great job, keep it up.
I am going to give it a try.
Close

#### by

on

Allowed html: a,b,br,blockquote,i,li,pre,u,ul,p

Email me replies to any of my messages in this thread

Allowed html: a,b,br,blockquote,i,li,pre,u,ul,p

Email me replies to any of my messages in this thread

4 Discuss

Login to InfoQ to interact with what matters most to you.