public class JpegHandler : IHttpHandler    {        public bool IsReusable        {            get { return true; }        }        public void ProcessRequest(HttpContext context)        {            string filename = context.Server.MapPath(context.Request.FilePath);            context.Response.ContentType = "image/jpeg";            if (context.Request.UrlReferrer == null                 || context.Request.UrlReferrer.Host == null                || !context.Request.UrlReferrer.Host.Contains("localhost")                )            {                context.Response.WriteFile("/image/error.jpg");            }            else            {                context.Request.ContentType = "image/jpeg";                context.Response.WriteFile(filename);            }        }    }

 

配置web.config