Question

为什么servlet里取不到cookie

Answer 1

string sa = Request.Cookies["ds"].Value.ToString ;
是sd不是sa,Cookies的Name。不妨采用下面的Sample定义Cookie
Page1:
HttpCookie cookieID = new HttpCookie("UserID", “Administrator”);
Response.Cookies.Add(cookieID);//add cookies userID
Response.Redirect("Page2.aspx");

Page2:
if (Request.Cookies["UserID"] != null)
userName = Request.Cookies["UserID"].Value;