cas-server默认配置的单点退出并没有做到真正的单点退出（在一个客户端退出时，另一个已经登录的客户端还能访问）。

springboot下设置单点退出：

    与spring设置单点退出相同，cas-server已经内置了此类功能，我们只需要加入一个拦截器与监听器就好。不过我发现FilterRegistrationBean中的setOrder设置拦截器顺序并不起作用，最后只能通过放置顺序控制拦截器的执行顺序。

SingleSignOutFilter拦截器设置，需要是第一个加载的拦截器。

  @Bean
    public SingleSignOutFilter singleSignOutFilter(){
        return new SingleSignOutFilter();
    }

    @Bean
    public FilterRegistrationBean singleSignOutFilterBean(){
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        filterRegistrationBean.setFilter(singleSignOutFilter());
//        filterRegistrationBean.addInitParameter("targetFilterLifecycle","true")
        filterRegistrationBean.setEnabled(true);
        filterRegistrationBean.addUrlPatterns("/*");
        filterRegistrationBean.setOrder(1);
        filterRegistrationBean.setName("singleFilter");
        System.out.println("================================singleFilter执行");
        return filterRegistrationBean;
    }

public SingleSignOutHttpSessionListener singleSignOutHttpSessionListener(){
    return new SingleSignOutHttpSessionListener();
}
@Bean
public ServletListenerRegistrationBean<SingleSignOutHttpSessionListener> singleSignOutHttpSessionListenerBean(){
    ServletListenerRegistrationBean<SingleSignOutHttpSessionListener> listenerRegistrationBean= new ServletListenerRegistrationBean<>();
    listenerRegistrationBean.setEnabled(true);
    listenerRegistrationBean.setListener(singleSignOutHttpSessionListener());
    listenerRegistrationBean.setOrder(3);
    listenerRegistrationBean.setName("singleListener");
    System.out.println("================================singleListener执行");
    return listenerRegistrationBean;