InternalAuthenticationProvider.java 文件源码

private String extractUserName(AbstractAuthenticationEvent appEvent) {
    if (appEvent.getSource() != null && appEvent.getSource() instanceof InternalAuthentication) {
        InternalAuthentication internalAuth = (InternalAuthentication) appEvent.getSource();

        if (internalAuth.getPrincipal() != null) {

            if (internalAuth.getPrincipal() instanceof User) {
                User user = (User) internalAuth.getPrincipal();
                return user.getUserName();
            }
            if (internalAuth.getPrincipal() instanceof String) {
                return (String) internalAuth.getPrincipal();
            }
        }
    }

    return null;
}