Resources cannot be null

问题错误提示：

HTTP Status 500 -

--------------------------------------------------------------------------------

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

java.lang.IllegalArgumentException: Resources cannot be null.
 org.apache.commons.validator.Validator.<init>(Validator.java:188)
 org.apache.struts.validator.Resources.initValidator(Resources.java:475)
 org.apache.struts.validator.DynaValidatorForm.validate(DynaValidatorForm.java:104)
 org.apache.struts.action.RequestProcessor.processValidate(RequestProcessor.java:950)
 org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:207)
 org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
 org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
 javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
 javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
note The full stack trace of the root cause is available in the Apache Tomcat/5.0.28 logs.

--------------------------------------------------------------------------------

Apache Tomcat/5.0.28
有很多朋友在问同一个问题，其实问题很小的，请看下面错误例子：

1、JSP不用改变，例如，建立register.jsp，源代码如下：(不得了啦，这里上传HTML源代码，被解释成一个HTML页面效果了)

<form name="form1" accept-charset="UNKNOWN" action="registerAction.do" method="post" > <table cellSpacing="0" cellPadding="3" width="301" border="0"> <tr> <td noWrap="true" width="61">用户名：</td> <td width="196"> <input type="text" name="userName" /> </td> </tr> <tr> <td height="30"> <td noWrap="true" height="30">密　码：</td> <td> <input type="password" name="userPassword1" /> </td> </tr> <tr> <td height="30"> <div align="center"></div> </td> <td noWrap="true" height="30">确　认：</td> <td> <input type="password" name="userPassword2" /> </td> </tr> <tr> <td height="30"> </tr> <input type="submit" value=" 确 定 " /> </td> </tr> </tbody> </table> </form> 本文来自优快云博客，转载请标明出处：http://blog.youkuaiyun.com/myok6/archive/2009/03/20/4006391.aspx

2、不用写ActionForm子类文件

3、需要在struts-config.xml文件中加入如下actionForm映射：

   <form-bean name="registerActionForm（虚构的）" type="org.apache.struts.action.DynaActionForm">
    <form-property name="userName"         type="java.lang.String" />
    <form-property name="userPassword1" type="java.lang.String" />
    <form-property name="userPassword2" type="java.lang.String" />
    <form-property name="userEmail"         type="java.lang.String" />
  </form-bean>
 
4、添加Action子类RegisterAction，其代码如下：
package com.drc.action;
 
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.DynaActionForm;
public class RegisterAction extends Action {
    public ActionForward execute(ActionMapping actionMapping,
                                 ActionForm form,
                                 HttpServletRequest httpServletRequest,
                                 HttpServletResponse httpServletResponse) {
        /**@todo: complete the business logic here, this is just a skeleton.*/
          DynaActionForm form = (DynaActionForm) form;
          System.out.println("userName          = " + form.get("userName"));
          System.out.println("userPassword1  = " + form.get("userPassword1"));
          return actionMapping.findForward("registerSuccess");
    }
}
 
5、在struts-config.xml中添加如下Action映射说明：
    <action input="/register.jsp"
                 name="registerActionForm"
                 path="/registerAction"
                 scope="request"
                 type="com.drc.action.RegisterAction"
                 validate="true">//很多问题都出在这儿,这儿应该是validate="false"，好多朋友把validate="false"写成了validate="true"，但因为程序中没有配置validate，相关说明请参看 http://book.youkuaiyun.com/bookfiles/604/10060419564.shtml
        <forward name="registerSuccess"
                        path="/userRegisterSuccess.jsp"
                        redirect="false" />
    </action>
 
6、如果想在validator中执行验证，与一般ActionForm方式一样

文章来自： http://blog.youkuaiyun.com/myok6/archive/2009/03/20/4006391.aspx