Indeed, you cannot use the "good old" JSTL in Facelets anymore the way as you would do in JSP. Facelets only supports a limited subset of JSTL (and has it already builtin, the JSTL JAR file is in fact superfluous).
You're forced to write a custom tag or better, a custom EL function, for this purpose.
Let's assume that we want to be able to do this:
<ice:graphicImage ... title="#{fmt:formatDate(bean.date, 'yyyy-MM-dd')}" />
Roughly said thus the same what the JSTL <fmt:formatDate> tag can do, but then in flavor of an EL function so that you can use it everywhere without the need for an "intermediating" tag. We want it to take 2 arguments, a Date and a SimpleDateFormat pattern. We want it to return the formatted date based on the given pattern.
First create a final class with a public static method which does exactly that:
package com.example.el;
import java.text.SimpleDateFormat;
import java.util.Date;
public final class Formatter {
private Formatter() {
// Hide constructor.
}
public static String formatDate(Date date, String pattern) {
return new SimpleDateFormat(pattern).format(date);
}
}
Then define it as a facelet-taglib in /META-INF/formatter.taglib.xml:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE facelet-taglib PUBLIC
"-//Sun Microsystems, Inc.//DTD Facelet Taglib 1.0//EN"
"http://java.sun.com/dtd/facelet-taglib_1_0.dtd">
<facelet-taglib>
<namespace>http://example.com/el/formatter</namespace>
<function>
<function-name>formatDate</function-name>
<function-class>com.example.el.Formatter</function-class>
<function-signature>String formatDate(java.util.Date, java.lang.String)</function-signature>
</function>
</facelet-taglib>
Then familarize Facelets with the new taglib in the existing /WEB-INF/web.xml:
<context-param>
<param-name>facelets.LIBRARIES</param-name>
<param-value>/META-INF/formatter.taglib.xml</param-value>
</context-param>
(note: if you already have the facelets.LIBRARIES definied, then you can just add the new path commaseparated)
Then define it in the Facelets XHTML file as new XML namespace:
<html
xmlns="http://www.w3.org/1999/xhtml"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:fmt="http://example.com/el/formatter"
...
>
Finally you can use it as intended:
<ice:graphicImage ... title="#{fmt:formatDate(bean.date, 'yyyy-MM-dd')}" />
Hope this helps.
