“Custom JSTL tags” makes honestly no sense. This term is utterly meaningless. JSTL is already a taglib at its own. Please carefully read the introductory paragraphs of our JSTL wiki page to learn what JSTL really is. You perhaps actually meant “Custom JSP tags“. Of course they would not work in Facelets as that’s a completely different view technology than JSP and actually the successor of the deprecated JSP.
Well, the analogy of a “Custom JSP tag” is a “Custom Facelets tag”, or more commonly “Facelets tag file”. It’s rather simple, you can follow the same syntax as an include file.
/WEB-INF/tags/some.xhtml:
<ui:composition xmlns:ui="http://java.sun.com/jsf/facelets">
Hello World
...
<ui:insert /> <!-- This inserts tag body, if necessary. -->
</ui:composition>
and register it in /WEB-INF/example.taglib.xml as follows:
<?xml version="1.0" encoding="UTF-8"?>
<facelet-taglib
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-facelettaglibrary_2_0.xsd"
version="2.0">
<namespace>http://example.com/jsf/facelets</namespace>
<tag>
<tag-name>some</tag-name>
<source>tags/some.xhtml</source>
</tag>
</facelet-taglib>
which is in turn registered in /WEB-INF/web.xml as follows:
<context-param>
<param-name>javax.faces.FACELETS_LIBRARIES</param-name>
<param-value>/WEB-INF/example.taglib.xml</param-value>
</context-param>
(note that registration in web.xml is unnecessary when the *.taglib.xml file is in /META-INF folder of a JAR in /WEB-INF/lib)
and finally use it in your templates as follows:
<html ... xmlns:my="http://example.com/jsf/facelets">
...
<my:some />