巨大的建筑，总是由一木一石叠起来的，我们何妨做做这一木一石呢？我时常做些零碎事，就是为此。

这是对的，但是我没有说过这句话！ —— 鲁迅

代码如下，报错了：

protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    //当调用了下面的startWebSocket函数后，该socket就会和相应的listener建立起对应关系
    WebSocketListener listener = new MyWebSocketListener(myWebSocketService);
    ShiroHttpServletRequest sr = (ShiroHttpServletRequest) req;
}

ShiroHttpServletRequest sr = (ShiroHttpServletRequest) req;

这个request的类型是 HttpServletRequest ，强制转换成 ShiroHttpServletRequest 报错，这是之前的代码，肯定没问题，说明这个request本身就是 ShiroHttpServletRequest

跟一下代码，发现HttpServletRequest是如何一步步的变成ShiroHttpServletRequest的。

AbstractShiroFilter中有如下代码：

 protected ServletRequest wrapServletRequest(HttpServletRequest orig) {
        return new ShiroHttpServletRequest(orig, getServletContext(), isHttpSessions());
 }

是在这里进行了一层包裹，重建，生成的,具体调用路径，经分析为如下：

DelegatingFilterProxy(invokeDelegate)->
OncePerRequestFilter(doFilter)->
AbstractShiroFilter(doFilterInternal->prepareServletRequest->wrapServletRequest)

现在就定位到了DelegatingFilterProxy，查看之前的代码，DelegatingFilterProxy的定义是在web.xml中定义的，如下：

<filter>
    <filter-name>shiroFilter</filter-name>
    <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
    <init-param>
        <param-name>staticSecurityManagerEnabled</param-name>
        <param-value>true</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>shiroFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

解决方法：将这个DelegatingFilterProxy转换为spring-boot的方式。如下：

@Configuration
public class WebConfig {
  @Bean
  public FilterRegistrationBean<DelegatingFilterProxy> delegatingFilterProxy() {
    FilterRegistrationBean<DelegatingFilterProxy> filterRegistrationBean = new FilterRegistrationBean<>();
    DelegatingFilterProxy shiroFilter = new DelegatingFilterProxy();
    filterRegistrationBean.setFilter(shiroFilter);//注入的bean不为null
    filterRegistrationBean.addUrlPatterns("/*");//配置过滤规则
    filterRegistrationBean.setName("shiroFilter");
    filterRegistrationBean.setOrder(2);//执行次序
    return filterRegistrationBean;
  }
}

重新启动，则可以正常