Build a Spring-Boot REST service with Basic Authentication for several users

This post describes how to build a REST service with Spring-Boot that uses Basic-Authentication for several users and that uses the username of the authenticated user to do it’s work. Warning: A service using basic authentication should always use HTTPS as transport protocol, either by running behind a web server proxy or by setting up HTTPS by itself. I’ll cover the latter in a later post. This might be a setup for a service, where for each user, data is stored in a database, so it not only is necessary to authenticate the user to use the service, but it is also necessary in the service to know which user is accessing the service.