servlet向jsp传值出现404.

servlet里是这样写的
request.setAttribute( "artId",y);
request.getRequestDispatcher( "articleDetail.jsp").forward(request,response);
然后就报错，说我的jsp不存在
HTTP Status 404 - /xxbbs/com.xx.servlet/articleDetail.jsp

type Status report

message /xxbbs/com.xx.servlet/articleDetail.jsp

description The requested resource is not available.

但是这个jsp是存在的呀