Use user-defined functions in El expressions

I,Java

 
Package test. utils. CTAG; public class customtags {public static Boolean equals (string S1, string S2) {If (S1 = S2) return true; If (S1! = NULL) return s1.equals (S2); Return false ;}}
 

II,TLD

<? XML version = "1.0" encoding = "UTF-8"?> <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"> <tlib-version> 1.0 </tlib-version> <JSP-version> 2.0 </JSP-version> <short-name> F </short-Name> <function> <Name> equals </Name> <function-class> test. utils. CTAG. customtags </function-class> <function-signature> Boolean equals (Java. lang. string, Java. lang. string) </function-signature> </function> </taglib>
 

Iii. Web. xml

<JSP-config> <taglib-Uri>/funtions </taglib-Uri> <taglib-location>/WEB-INF/classes/functions. TLD </taglib-location> </taglib> </JSP-config>
 

Iv. jsp

 
<% @ Taglib prefix = "F" uri = "/functions" %>
 

 
$ {F: equals ("hello", "hello")} <br/>$ {f: equals ("hello", "world ")} <br/>$ {f: equals (null, "world ")}