@WebListener
public class ServletContextListenerDemo implements ServletContextListener{

    @Override
    public void contextInitialized(ServletContextEvent servletContextEvent) {

    }

    @Override
    public void contextDestroyed(ServletContextEvent servletContextEvent) {

    }
}
 

ServletContextAttributeListener

@WebListener
public class ServletContextAttributeListenerDemo implements ServletContextAttributeListener {

    @Override
    public void attributeAdded(ServletContextAttributeEvent servletContextAttributeEvent) {

    }

    @Override
    public void attributeRemoved(ServletContextAttributeEvent servletContextAttributeEvent) {

    }

    @Override
    public void attributeReplaced(ServletContextAttributeEvent servletContextAttributeEvent) {

    }
}
 

說明：servletContext上下文監聽器，是整個應用在啟動的時候加載的context.一個web application只會有一個context.因此，servletContext是對整個appliction全程有效的。

servlet context listener