我必須從我的User班級中刪除一個登錄字段并email在 SecurityUtils 中用作用戶名我已經j_username在前端更改了參數，但現在問題仍然存在于后端public static String getCurrentUserLogin() {        SecurityContext securityContext = SecurityContextHolder.getContext();        Authentication authentication = securityContext.getAuthentication();        String userName = null;        if (authentication != null) {            if (authentication.getPrincipal() instanceof UserDetails) {                UserDetails springSecurityUser = (UserDetails) authentication.getPrincipal();                userName = springSecurityUser.getUsername();            } else if (authentication.getPrincipal() instanceof String) {                userName = (String) authentication.getPrincipal();            }        }        return userName;    }結果userName是空的，因為UserDetails并且Authentication沒有電子郵件。如何將字段設置email為“j_username”？我試過這個如何在春季安全中通過電子郵件而不是用戶名登錄解決方案，但這還不夠，因為我使用了anonymousUser另外，我有一個實現，UserDetailsService但是在調試時它不會被調用anonymousUserpublic class DomainUserDetailsService implements UserDetailsService {    private final UserRepository userRepository;    public DomainUserDetailsService(UserRepository userRepository) {        this.userRepository = userRepository;    }    @Override    public UserDetails loadUserByUsername(final String login) {        String lowercaseLogin = login.toLowerCase(Locale.ENGLISH);        Optional<User> userFromDatabase = userRepository.findOneByLogin(lowercaseLogin);        return userFromDatabase.map(user -> {            if (!user.getActivated()) {                throw new UserNotActivatedException("User " + lowercaseLogin + " was not activated");            }            List<GrantedAuthority> grantedAuthorities = user.getAuthorities().stream()                .map(authority -> new SimpleGrantedAuthority(authority.getName()))                .collect(Collectors.toList());            return new org.springframework.security.core.userdetails.User(lowercaseLogin,                user.getPassword(),                grantedAuthorities);    }}