只要请求没关闭，当前线程的任何地方都能注入HttpServletRequest

[coderstory]

@component
public class myAuthenticationProvider extends DaoAuthenticationProvider {
private HttpServletRequest request;

public myAuthenticationProvider(UserDetailsService userDetailsService, HttpServletRequest request, PasswordEncoder passwordEncoder) {
    this.request = request;
    // 注意是使用set
    this.setUserDetailsService(userDetailsService);
    this.setPasswordEncoder(passwordEncoder);
}

@Override
protected void additionalAuthenticationChecks(UserDetails userDetails,
                                              UsernamePasswordAuthenticationToken authentication) throws AuthenticationException {
    super.additionalAuthenticationChecks(userDetails, authentication);
}

}
4.2章节里为什么搞得这么麻烦？
P53页看的时候 就感觉不太对
不知道这些代码的内容是怎么来的。。。很多代码都是new对象而不是注入