How to get a request url hash on the back end server. Reconstructing the full request url in a servlet.

It is impossible, the browser does not include the hash into the request url sent to the server:

Just a note for myself on what values of the request path can be extracted from HttpServletRequest in a servlet:

The full request path can be reconstructed by a function like:

request.getRequestURL() + (request.getQueryString() != null ? ("?" + request.getQueryString()) : "")