Raible Designs

This works in tomcat 5.0.x too. But it has one disadvantage - it removes all whitespace between two JSP tags, even when you might one one space. For example, something like <c:out value="Hello"/> <c:out value="${name}"/> will now say, "HelloMatt".

It's the thought of searching through all my JSPs for these types of problems which has put me off using it.

Oh, the jasper ant task has a flag to do the same thing if you pre-compile your JSPs...

Posted by Kris on March 24, 2005 at 01:08 AM MST #

Posted by Larry Williams on March 24, 2005 at 01:59 AM MST #

<quote>"I've been wondering why the JSP compiler creates whitespace"<quote>

The JSP compiler doesn't *create* the whitespace. The whitespace already exists in the source document and the JSP compiler just doesn't remove it (Why would it? The whitespace is outside any JSP tags). If you remove the line breaks between JSP tags then there will be none in the generated HTML.

Not this

<%@ page import="org.apache.log4j.*" %>
<%@ page errorPage="/Error.jsp" %>

But this

<%@ page import="org.apache.log4j.*" %><%@ page 
errorPage="/Error.jsp" %>

Of course then your JSP is ugly and hard to read. Pick which one bugs you least or post-process the generated html, which I'm guessing is what the Tomcat switch enables.

Posted by Steve Raeburn on March 24, 2005 at 02:12 PM MST #

Posted by Charles Havener on March 25, 2005 at 03:09 PM MST #

Posted by Michael Musson on April 05, 2005 at 11:01 AM MDT #

Posted by Noruas on March 14, 2006 at 07:26 AM MST #

Posted by Patrick O'Sullivan on August 23, 2006 at 06:20 AM MDT #

Posted by todd hodes on September 12, 2006 at 08:07 PM MDT #

Posted by zzAA on May 23, 2007 at 01:42 AM MDT #

Hey guys,

The solution provided below works great too!

1. Keep trimFlt.jar in WEB-INF\lib folder

Download this jar from the reference link provided at the end.

2. Add following entries in web.xml

 <filter> 
   <filter-name>trimFilter</filter-name> 
   <filter-class>com.cj.trim.trimFilter</filter-class> 
 </filter>
 
 <filter-mapping>
   <filter-name>trimFilter</filter-name> 
   <url-pattern>/*</url-pattern>
 </filter-mapping>

To remove other HTML comments the filter parameter can be changed to -

<filter> 
  <filter-name>trimFilter</filter-name> 
  <filter-class>com.cj.trim.trimFilter</filter-class> 
  <init-param> 
    <param-name>removeComments</param-name> 
    <param-value>true</param-value> 
  </init-param> 
</filter>

The performance impact of this fix is yet to be analysed.

Reference that I used - http://www.servletsuite.com/servlets/trimflt.htm

Posted by Ashish Nair on July 03, 2007 at 03:43 AM MDT #

Posted by Sanath Kodikara on July 11, 2007 at 12:41 AM MDT #

Posted by Raible Designs on August 01, 2007 at 05:02 PM MDT #

The trimFlt.jar mentioned above works great for standard HTML streams, but we're having problems getting it filter XHTML-MP for some reason. Is there any deeper documentation and/or any way to contact the developer? The servletsuite site is rather content-free, and I'd probably purchase the "commercial license" for $49, but only if I knew that buying it would give me more direct access to the developer and/or the code itself.

Any ideas?

Posted by Ken Scott on November 06, 2007 at 04:08 AM MST #

Posted by David Truong on January 30, 2008 at 01:52 PM MST #

<!-- Strip whitespace -->
    <replaceregexp match=">\s*<" replace="> <" flags="g" byline="false">
      <fileset dir="${build.home}" includes="**/*.html,**/*.htm,**/*.jsp,**/*.tag"/>
 </replaceregexp>

Posted by Sam Allen on April 04, 2008 at 04:55 AM MDT #

Actually, IMHO this fact doen't matter at all for HTML, CSS and Javascript contents IF YOU CONFIGURE YOUR SERVER TO SERVE COMPRESSED CONTENTS for the textual mime-types (you can see tons of articles googling, for example a post written in Spanish in my blog: http://serverperformance.blogspot.com/2008/05/compresin-http.html).

I mean, patterns like tons of spaces or tabs have great compression ratios with gzip. For example I had an unoptimized JSP which sent to the browser 5,8 KBytes of html text. When eliminating carriage returns, spaces and tabs, I got a 3,5 KBytes content (hey, thats good). But when compressing the contents, in the first case 1,2 KBytes were sent though the network, and 1,1 KBytes in the second case.

So the actual difference isn't enough to worth it, at least in the 99% of the cases.

P.S: This comment is valid for HTML, Javascript and CSS contents, but surely no for JSON contents in response to AJAX requests because the JSON parser is a Javascript code and in the optimized case has to do more work for parsing it...

My 2 cents.
Regards

Posted by Server Performance on October 09, 2008 at 03:48 AM MDT #

Posted by Will on January 31, 2010 at 10:15 AM MST #

Posted by Matt Raible on September 30, 2010 at 03:00 PM MDT #