在执行登录过程时，spring boots会将用户配置文件保存在内存中。例如，如果为已登录的用户添加新角色并保存在数据库中，则内存中的用户配置文件不会更改，因此必须更新此数据。
您可以使用：

User user = userService.findById(idUser);
    SecurityContextHolder.getContext().setAuthentication(new UsernamePasswordAuthenticationToken(user, user.getPassword(), user.getRoles()));

使用此命令，可以更新spring安全内存中的用户配置文件。

谢谢大家，我找到了解决办法。
...
@启用Web安全
公共类securityconfig扩展了WebSecurityConfigureAdapter{

@Autowired
MyUserDetailsService myUserDetailsService;

Logger logger = Logger.getLogger(this.getClass());

@Override
protected void configure(HttpSecurity http) throws Exception {

    http.csrf().disable();

    http.addFilterBefore(new loginFilter(), AnonymousAuthenticationFilter.class).
            authorizeRequests().antMatchers("/","/register/**","/log/**").permitAll();

    http.formLogin().loginPage("/log/toLogin")
                    .loginProcessingUrl("/log/login") 
                    .usernameParameter("memacc")
                    .passwordParameter("mempwd");
    http.logout().logoutSuccessUrl("/");
}
@Override
protected void configure(AuthenticationManagerBuilder auth) throws Exception {
    auth.userDetailsService(myUserDetailsService);
}

} ...
使用类implement userdetailsservice interface。当用户登录时，验证该用户。
... @服务公共类myuserdetailsservice实现userdetailsservice{

@Autowired
MemberMapper memberMapper;

@Override
public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {

    Members member = memberMapper.getOneMemberByMemacc(username);
    if(member == null)
        throw new UsernameNotFoundException(username + " not found");
    UserDetails userDetails = User.builder()
            .username(member.getMemacc())
            .password("{noop}" + member.getMempwd())
            .roles(member.getRoleList()).build();
    return userDetails;
}

} ...