HTTP/1.1 200 OK Content-Type: application/pdf Last-Modified: Mon, 06 Jan 2014 02:14:20 GMT Accept-Ranges: bytes ETag: "0cc4b285acf1:0" Server: 微软-IIS/7.5 X-Powered-By: ASP.NET Date: Tue, 22 Jan 2019 20:36:49 GMT Content-Length: 0