什么物理路径？它是一个物理文件，因此必须存储在物理路径中！

What physical path? It is a 'physical' file so must be stored in a physical path!

MapPath方法映射指定服务器上相应物理目录的相对或虚拟路径。

The MapPath method maps the specified relative or virtual path to the corresponding physical directory on the server.

所以没关系... SaveAs方法将文件保存在物理路径中〜 / Documents虚拟路径点......

So it is all right...The SaveAs method will save the file in the physical path where the "~/Documents" virtual path points...