struts上床文件的问题

我想用struts写一个上传文件的页面，出现如下错误，type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException: Exception in JSP: /index.jsp:1411:  <p/>UserName:<html:text property="userName"/>
12:  <p/>Password:<html:password property="password"/>
13: 
14:  <html:file property="allanFile"  errorStyle="background-color: yellow" />
15:  <p/><html:submit/>
16:  </html:form>
17:  </body>
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:506)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
root cause javax.servlet.ServletException: No getter method for property: "allanFile" of bean: "UploadFileForm"
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:843)
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:776)
org.apache.jsp.index_jsp._jspService(index_jsp.java:85)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:334)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
root cause javax.servlet.jsp.JspException: No getter method for property: "allanFile" of bean: "UploadFileForm"
org.apache.struts.taglib.TagUtils.lookup(TagUtils.java:903)
org.apache.struts.taglib.html.BaseFieldTag.prepareValue(BaseFieldTag.java:120)
org.apache.struts.taglib.html.BaseFieldTag.renderInputElement(BaseFieldTag.java:99)
org.apache.struts.taglib.html.BaseFieldTag.doStartTag(BaseFieldTag.java:77)
org.apache.jsp.index_jsp._jspx_meth_html_file_0(index_jsp.java:183)
org.apache.jsp.index_jsp._jspx_meth_html_form_0(index_jsp.java:116)
org.apache.jsp.index_jsp._jspService(index_jsp.java:75)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:334)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
note The full stack trace of the root cause is available in the Apache Tomcat/5.5.20 logs.
--------------------------------------------------------------------------------而实际上我的FromBean中有这个方法：
import org.apache.struts.action.ActionForm;
import org.apache.struts.upload.FormFile;public class UploadFileForm extends ActionForm{
private String userName;
private String password;
protected FormFile allanFile;

public UploadFileForm(){

}

public void setUserName(String userName){this.userName = userName;}
public String getUserName(){return userName;}

public void setPassword(String password){this.password = password;}
public String getPassword(){return password;}

public void setAllanFile(FormFile allanFile){this.allanFile = allanFile;}
public FormFile getAllanFile(){return allanFile;}

}疑惑中