JSP 2 and Servlet 2.4 broke my custom tags

Question

Hello experts,

We recently switched to Servlet 2.4 and JSP 2 on a project and our custom tags no longer work. We have tags like:

<myTags:someTag value="${x}" />

and once in the tag we evaluated x bean and went from there. Now the evaluation happens directly in the JSP and we get a String (apparently x.toString()) set for the value attribute.

There are not a lot of tags and I could adapt them in a few days but how can I do that? I could not find anything on the web (or maybe I'm not looking where I should).

How do I pass the x bean to my tag and evaluate it there and not allow it to be evaluated in the JSP?

P.S. I do not want to deactivate the EL-engine

Thank you!

Answer 1

If you redeclare web.xml as Servlet 2.4 as follows

<web-app 
    xmlns="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
    version="2.4">

and the tld file as JSP 2.0 taglib as follows:

<taglib 
    xmlns="http://java.sun.com/xml/ns/j2ee" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd" 
    version="2.0"> 

Then you can add <rtexprvalue>true</rtexprvalue> entries to tag attributes in the TLD file which are expecting EL values. E.g.

<attribute>
    <name>value</name>
    <rtexprvalue>true</rtexprvalue>
</attribute>

It namely defaults to false.