第一種模式：同一頂級域名下cookie共享，代碼如下
HttpCookie cookies = new HttpCookie("Token");
cookies.Expires = DateTime.Now.AddDays(7);
cookies.Path = "/";
cookies.Domain = "xxxx.com";//設置同一頂級域名
cookies.Value = "token的值";
System.Web.HttpContext.Current.Response.Cookies.Add(cookies);
第二種模式：跨域下實現單點登錄