java.lang.IllegalArgumentException: The path of an ForwardConfig cannot be null__path

轉自：http://hi.baidu.com/bareearthling/blog/item/a8ac8981e9371adfbc3e1e3c.html

該異常是struts加入驗證時配置裡面沒有寫上input屬性，

因為驗證出錯的話會跳回input指向的頁面

如下紅色部分：

<action path="/customerRegeditAction" name="customerRegActionForm"
    type="org.springframework.web.struts.DelegatingActionProxy"
    cancellable="true" validate="true" input="/customer/login.jsp">
    <forward name="loginCancle" path="/index.jsp"></forward>
    <forward name="sucess" path="/customer/index_login.jsp"></forward>
    <forward name="fail" path="/index.jsp"></forward>
    <forward name="hadRegedit" path="/customer/customer_reg.jsp"></forward>

就會報這個異常