java.lang.ClassCastException: org.apache.struts.action.ActionMessage 錯誤

java.lang.ClassCastException: org.apache.struts.action.ActionMessageorg.apache.struts.taglib.html.ErrorsTag.doStartTag(ErrorsTag.java:215)org.apache.jsp.login_jsp._jspx_meth_html_005ferrors_005f0(login_jsp.java:173)org.apache.jsp.login_jsp._jspx_meth_html_005fform_005f0(login_jsp.java:115)org.apache.jsp.login_jsp._jspService(login_jsp.java:77)org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)javax.servlet.http.HttpServlet.service(HttpServlet.java:803)org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)javax.servlet.http.HttpServlet.service(HttpServlet.java:803)org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1069)org.apache.struts.action.RequestProcessor.internalModuleRelativeForward(RequestProcessor.java:1012)org.apache.struts.action.RequestProcessor.processValidate(RequestProcessor.java:980)org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:255)org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)javax.servlet.http.HttpServlet.service(HttpServlet.java:710)javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

將 

   ActionErrors error=new ActionErrors();
   if ("login".equals(status)) {
   if (this.id == null || "".equals(this.id)) {
    error.add("id", new ActionMessage("id.null"));
   }
  }

該為

   ActionErrors error=new ActionErrors();
   if ("login".equals(status)) {
   if (this.id == null || "".equals(this.id)) {
    error.add("id", new ActionError("id.null"));
   }
  }
就可以了 ActionError比ActionMessage好用