1.編寫java類
- package myEL;
- public class ELFun {
- public static String processStr(String s) {
- s=s.toUpperCase();
- return s;
- }
- }
EL函數對應的java類的方法必須是靜態的
2.編寫tld文件
- <?xml version="1.0" encoding="UTF-8"?>
- <taglib version="2.0" 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">
- <tlib-version>1.0</tlib-version>
- <uri>myelfun</uri>
- <function>
- <name>elfunction</name>
- <function-class>myEL.ELFun</function-class>
- <function-signature>
- java.lang.String processStr(java.lang.String)
- </function-signature>
- </function>>
- </taglib>
TLD文件的擴展名必須是.tld
3.web.xml配置
- <jsp-config>
- <taglib>
- <taglib-uri>/WEB-INF/TLD/elfun.tld
- </taglib-uri>
- <taglib-location>
- /WEB-INF/TLD/elfun.tld
- </taglib-location>
- </taglib>
- </jsp-config>
4.jsp中調用
- <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
- <%
- String path = request.getContextPath();
- String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
- %>
- <%@ taglib uri="/WEB-INF/TLD/elfun.tld" prefix="elfun" %>
- <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
- <html>
- <head>
- <base href="<%=basePath%>">
- <title>My JSP 'elfun.jsp' starting page</title>
- <meta http-equiv="pragma" content="no-cache">
- <meta http-equiv="cache-control" content="no-cache">
- <meta http-equiv="expires" content="0">
- <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
- <meta http-equiv="description" content="This is my page">
- <!--
- <link rel="stylesheet" type="text/css" href="styles.css">
- -->
- </head>
- <body>
- <form method="POST">
- 請輸入一個字符串:
- <input type="text" name="text"/>
- <p>
- <input type="submit" value ="提交"/>
- </form>
- <p>
- 直接輸出文本框中的內容:
- <p>
- ${param.text }
- <p>
- ${elfun:elfunction(param.text)}
- <p>
- <br>
- </body>
- </html>
如果用URI引用TLD文件,JSP引擎會先在WEB-INF目錄及子目錄中尋找所有的*.tld文件,如果發現某個.tld文件中的<uri>標籤定義的URI和talib中的uri屬性的值相等,就會記住這個.tld路徑,在生成servlet的同時就會將這個TLD文件的路徑也加進來。