@Override
  public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
    //方法调用前执行
    return true;//返回为false,拦截器拦截的方法不会调用
  }
  @Override
  public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
  //方法执行结束后执行
  }
  @Override
  public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
  //该方法将在整个请求完成之后，也就是DispatcherServlet渲染了视图执行, 这个方法的主要作用是用于清理资源的，
  }  

 @Autowired
  private LoginInterceptor loginInterceptor;//自己定义的拦截器类
  @Override
  public void addInterceptors(InterceptorRegistry registry) {
  registry.addInterceptor(loginInterceptor).addPathPatterns("拦截URL，可以不填默认全部请求拦截");
  }