struts1标签错误，提示html:text property method不存在


<%@ page language="java" contentType="text/html; charset=windows-31j"
    pageEncoding="windows-31j"%>
<%@ taglib uri="/WEB-INF/struts-html.tld" prefix="html" %>    
<%@ taglib uri="/WEB-INF/struts-bean.tld" prefix="bean" %>   
<%@ taglib uri="/WEB-INF/struts-logic.tld" prefix="logic" %>   
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=windows-31j">
<title>Insert title here</title>
</head>
<body>
1. html link</br>
<html:link page="/test/linked_page.jsp">linked_page</html:link>
<html:link forward="success">forward_success</html:link>2 html form</br>
<html:form action="saveProduct" method="post">
<html:text property="user" value=""/>
<html:checkbox property="ah" value="1">sports</html:checkbox>
<html:checkbox property="ah" value="2">swimming</html:checkbox>
</html:form>
</body>
</html>
界面如上。报错的信息如下：
javax.servlet.jsp.JspException: Bean org.apache.struts.taglib.html.BEAN のプロパティ ah に対するゲッターメソッドがありません
at org.apache.struts.taglib.TagUtils.lookup(TagUtils.java:973)
at org.apache.struts.taglib.html.CheckboxTag.isChecked(CheckboxTag.java:154)
at org.apache.struts.taglib.html.CheckboxTag.doStartTag(CheckboxTag.java:129)
at org.apache.jsp.test1_005fhtml_jsp._jspx_meth_html_005fcheckbox_005f0(test1_005fhtml_jsp.java:264)
at org.apache.jsp.test1_005fhtml_jsp._jspx_meth_html_005fform_005f0(test1_005fhtml_jsp.java:209)
at org.apache.jsp.test1_005fhtml_jsp._jspService(test1_005fhtml_jsp.java:97)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:877)
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:594)
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1675)
at java.lang.Thread.run(Unknown Source)
翻译过来就是bean对应的属性，方法不存在。不清楚这里要什么方法~~~