EL 運算式中使用自訂函數

一、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;}}

二、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>

三、web.xml

  <jsp-config>    <taglib>        <taglib-uri>/functions</taglib-uri>        <taglib-location>/WEB-INF/classes/functions.tld</taglib-location>    </taglib>  </jsp-config>

四、Jsp

<%@ taglib prefix="f" uri="/functions" %>

${f:equals("Hello","Hello")}<br/> ${f:equals("Hello","World")}<br/> ${f:equals(null,"World")}