I would like to log in knowing only the username

[nunziaandrulli]

I would like to log in knowing only the username

[klaus (Klaus Pfeiffer)]

Then you have to dive a bit into spring security. Here is some kotlin example code, maybe it will help you a bit:

    @Autowired
    private lateinit var userDetailsService: UserDetailsService

...


val loadedUser: UserDetails = userDetailsService.loadUserByUsername(username)

val authentication = UsernamePasswordAuthenticationToken.authenticated(
    loadedUser,
    null,
    loadedUser.authorities
)

SecurityContextHelper.setAuthentication(authentication)