獲取自定義URL的絕對地址
string path = "http:/localhost:8204/FormDocFiles/2020/19/20190911000020.doc";
string path1 = ((System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create(path )).Address.LocalPath;
string path2 = HttpContext.Current.Server.MapPath(path);
//輸出
//path1:../FormDocFiles/2020/19/20190911000020.doc
//path2:D:/htmTopdf/FormDocFiles/2020/19/20190911000020.doc