This blog talks about how to create an http alias pointing to a path in the actual file structure of the Web Aplication Server.
For eg: I have created an alias “test\rja” and mapped it to the path “E:\usr\sap\J2E\JC00\j2ee\cluster\server0\temp\rja”.
To show this works, copy an HTML file and put in this folder as shown below.
Access this HTML page using the HTTP alias as part of the URL.