Add users dynamically in Spring Java - spring

Question

This code I use to add users from my database that can authenticate but the problem this code is executed once , I want to have users that register how can I achieve that ?
I have this solution How to adding new user to Spring Security in runtime but I coudn't add it to my actual code please help.
this is my code
#Configuration
#EnableWebSecurity
protected static class SecurityConfig extends WebSecurityConfigurerAdapter {
#Autowired
DataSource dataSource;
#Autowired
UserRepository userRepository;
#Override
protected void configure(AuthenticationManagerBuilder auth) throws Exception {
for (UsersEntity user : userRepository.findAll())
if (user.getUsername() != null && user.getPassword() != null)
auth.
inMemoryAuthentication()
.passwordEncoder(UsersEntity.ENCODE_PASS)
.withUser(user.getUsername()).password(user.getPassword())
.roles("USER");
}
#Bean
#Override
public AuthenticationManager authenticationManagerBean()
throws Exception {
return super.authenticationManagerBean();
}
}

Answer 1

You can simply set another authenticationProvider.
#Autowired
private MyAuthenticationProvider authenticationProvider;
protected void configure(AuthenticationManagerBuilder auth) throws Exception {
auth.authenticationProvider(authenticationProvider);
}
Simply implement your own MyAuthenticationProvider that asks your UserRepository for each login attempt. Or another way would be to simply use basic jdbc:
protected void configure(AuthenticationManagerBuilder auth) throws Exception {
auth.jdbcAuthentication().dataSource(dataSource)
.usersByUsernameQuery(
"select username,password, enabled from users where username=?")
.authoritiesByUsernameQuery(
"select username, role from user_roles where username=?");
}
...of course, you would need to set your own queries there.