shiro 中获取servletContext 和WebApplicationContext

项目中用到shiro管理权限，但是shiro在spring容器中，某些类不在spring中初始化，但是想得到spring容器管理的bean，或者从shiro中获取servletContext，如下

		ServletRequest request = ((WebSubject)SecurityUtils.getSubject()).getServletRequest(); 
		HttpSession httpSession = ((HttpServletRequest)request).getSession(); 
		logger.debug("httpSession.getServletContext():"+httpSession.getServletContext());
		context = WebApplicationContextUtils.getWebApplicationContext(httpSession.getServletContext());