web.xml

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">

<display-name>el_function_helloworld</display-name>

<welcome-file-list>

<welcome-file>function.jsp</welcome-file>

</welcome-file-list>

<jsp-config>

<taglib>

<taglib-uri> http://jakarta.apache.org/tomcat/functions </taglib-uri>

<taglib-location> /WEB-INF/tlds/functions.tld </taglib-location>

</taglib>

</jsp-config>

</web-app>

这里的taglib-uri的值就是页面中引用的依据。