Spring注解无法注入Session监听器解决办法

public class DefaultSessionListener implements HttpSessionListener {

    public void sessionCreated(HttpSessionEvent arg0) {

    　　ApplicationContext ctx = WebApplicationContextUtils.getRequiredWebApplicationContext(arg0.getSession().getServletContext());
   　　 IMemberService memberService = (IMemberService) ctx.getBean("memberService"); // 填写要注入的类,注意第一个字母小写

    }

    public void sessionDestroyed(HttpSessionEvent se) {
    }
}