使用Session监听器无法监听到，各位大神帮帮忙

Question

我想做一个Session监听器，用来监听Session销毁和超时的状态，每次销毁时，执行修改数据库数据的一个方法，但是监听器实现HttpSessionListener,Tomcat启动不起来，报错严重: Error configuring application listener of class com.fh.listener.SessionListener
javax.naming.NamingException: Cannot create resource instance；如果监听器继承SessionListenerAdapter，开始Session和关闭Session又进不到监听器中的断点处，请各位大神帮帮忙，怎样解决这个问题，非常感谢！

错误代码
严重: Error configuring application listener of class com.fh.listener.SessionListener
javax.naming.NamingException: Cannot create resource instance
at org.apache.naming.factory.ResourceEnvFactory.getObjectInstance(ResourceEnvFactory.java:115)
at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:321)
at org.apache.naming.NamingContext.lookup(NamingContext.java:842)
at org.apache.naming.NamingContext.lookup(NamingContext.java:167)
at org.apache.catalina.core.DefaultInstanceManager.lookupFieldResource(DefaultInstanceManager.java:557)
at org.apache.catalina.core.DefaultInstanceManager.processAnnotations(DefaultInstanceManager.java:449)
at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:135)
at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:116)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4933)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5531)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1574)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1564)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)

Answer 1

Web容器启动的时候就是通过监听来管理Bean的。在监听HttpSessionListener是还未完成Bean的注入，可以使用
WebApplicationContext wb =WebApplicationContextUtils.getWebApplicationContext(arg0.getSession().getServletContext());
userService = (UserService)wb.getBean("userService");
来获取bean