ashx 接受 post json 请求

HttpContext.Current.Response.ContentType = "application/json";
            HttpContext.Current.Response.ContentEncoding = Encoding.UTF8;

Stream inputStream = HttpContext.Current.Request.InputStream;
                Encoding encoding = HttpContext.Current.Request.ContentEncoding;
                StreamReader streamReader = new StreamReader(inputStream, encoding);
                string strJson = streamReader.ReadToEnd();