tomcat启动后，在普通java类中获取spring管理的bean和ServletContext，（经过验证，可以取到）

//从spring容易中获取bean
public static Object getBean(String beanName){
ApplicationContext context = ContextLoader.getCurrentWebApplicationContext();
return context.getBean(beanName);
}
//获取ServletContext
public static ServletContext getServletContext(){
WebApplicationContext context = ContextLoader.getCurrentWebApplicationContext();
return context.getServletContext();
}