jsp 网页定义EL参数老报错。

这是JSP的代码：
<%@ page language="java" import="java.util.*" import="java.io.*" pageEncoding="UTF-8" isErrorPage="true"%>
<%@ taglib uri="/myfun" prefix="my"%> 
<jsp:directive.page import="java.io.PrintWriter"/><%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'two.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> 
 
    <%// 自定义EL函数
    //
    //
     %>
    <form>
     parameters:<input type="text" name="parameters">
     <input type="submit" value="开始">
    </form>
   lenght= ${my:lenght(param["text"]) }
    
    
    <%
    //自定义标签！！！
    //
     %>
     
     <jsp:element name="rain">
      <jsp:attribute name="work">sdfa</jsp:attribute>
      <jsp:body >he is a good man</jsp:body>
     </jsp:element>
     <br><br>
    
     
     
    <jsp:element name="names">
     <jsp:attribute name="names">rain</jsp:attribute>
     <jsp:body>
     he is a manager and very young!
     </jsp:body>
    </jsp:element>
     
  </body>
</html>
这是web.xml：<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" 
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 
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>Tadayfirst</servlet-name>
    <servlet-class>look.Tadayfirst</servlet-class>
  </servlet>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>A</servlet-name>
    <servlet-class>look.A</servlet-class>
  </servlet>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>B</servlet-name>
    <servlet-class>look.B</servlet-class>
  </servlet>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>Oneday</servlet-name>
    <servlet-class>look.Oneday</servlet-class>
  </servlet>
  <jsp-config>
    <taglib>
      <taglib-uri>
        /myfun
      </taglib-uri>
      <taglib-location>
        /WEB-INF/el-function.tld
      </taglib-location>
    </taglib>
  </jsp-config>  <servlet-mapping>
    <servlet-name>Tadayfirst</servlet-name>
    <url-pattern>/servlet/Tadayfirst</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>A</servlet-name>
    <url-pattern>/servlet/A</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>B</servlet-name>
    <url-pattern>/servlet/b</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>Oneday</servlet-name>
    <url-pattern>/servlet/Oneday</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>
这是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"  
 xmlns:shcemalocation="http://java.sun.com/xml/ns/j2ee    
 http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">  
    
 <description>自定义标签</description>  
 <display-name>JSTL core</display-name>  
 <tlib-version>1.1</tlib-version>  
 <short-name>firstLabel</short-name>  
 <uri>/myfun</uri>  
 
<function>
<description>Length</description>
<name>length</name>
<function-class>classes.look.Change</function-class>
<function-signature>
java.lang.String length( java.lang.String)
</function-signature>
</function>
    
</taglib>  这是JAVA类代码：package look;public class Change {

public static int length(String text){
return new StringBuffer(text).length();
}
public static String toUp(String text){
return text.toUpperCase();
}
}
JSP网页报错：HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException: /two.jsp(65,13) The function lenght cannot be located with the specified prefix
org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:40)
org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:407)
org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:148)
org.apache.jasper.compiler.Validator$ValidateVisitor$1FVVisitor.visit(Validator.java:1522)
org.apache.jasper.compiler.ELNode$Function.accept(ELNode.java:129)
org.apache.jasper.compiler.ELNode$Nodes.visit(ELNode.java:200)
org.apache.jasper.compiler.ELNode$Visitor.visit(ELNode.java:242)
org.apache.jasper.compiler.ELNode$Root.accept(ELNode.java:56)
org.apache.jasper.compiler.ELNode$Nodes.visit(ELNode.java:200)
org.apache.jasper.compiler.Validator$ValidateVisitor.validateFunctions(Validator.java:1531)
org.apache.jasper.compiler.Validator$ValidateVisitor.prepareExpression(Validator.java:1536)
org.apache.jasper.compiler.Validator$ValidateVisitor.visit(Validator.java:720)
org.apache.jasper.compiler.Node$ELExpression.accept(Node.java:958)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2361)
org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2411)
org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2417)
org.apache.jasper.compiler.Node$Root.accept(Node.java:495)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2361)
org.apache.jasper.compiler.Validator.validateExDirectives(Validator.java:1763)
org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:198)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:347)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:327)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:314)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:589)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:317)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:968)
org.apache.jsp.one_jsp._jspService(one_jsp.java:95)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.26 logs.请各位大哥帮帮忙哈。