Servlet listeners

Scope	Lifecycle listeners	Attribute change listeners	Register
Application	ServletContextListener	ServletContextAttributeListener	@WebListener
Servlet	HttpServlet		@PostConstruct @PreDestroy
Session	HttpSessionListener	HttpSessionAttributeListener	@WebListener
Request	ServletRequestListener	ServletRequestAttributeListener	@WebListener
Asynchronous Request	AsyncListener		AsyncContext#addListener

• Additional Session Listeners:
  • HttpSessionBindingListener: Notifies an attribute that it is bound/unbound from the session attribute map
  • HttpSessionActivationListener: Notifies an attribute that it is passivated to/activated from persistent storage (session passivation)
• WebListeners can also be registered using
  • web.xml
    ?

    1 2 3 4 5 6

    <web-app>   <listener>     <listener-class>org.edu.MyListener</listener-class>   </listener> … </web-app>

    
    
  
  
  
  • programmatically using ServletContext#addListener from a ServletContextListener
  
  
  
  



• Example of using a ServletContextListener