MVC中利用Filter验证用户登录状态

public class CheckinLoginAttribute:ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
if (filterContext.HttpContext.Session["user"] == null)
{
filterContext.HttpContext.Response.Redirect("/User/Login");
}
}
}

public class HomeController : Controller
{
//
// GET: /Home/

[CheckinLogin]
public ActionResult Index()
{
return View();
}

}