有关信息请跳转这里
ServletContextListener：监听servletContextListener对象的创建和销毁
ServletContextAttributeListener：监听servletContextListener对象里的数据的增删改
示例：
public class Listener implements ServletContextListener,ServletContextAttributeListener{
/*------------------------application监听器-----------------------------------------*/
@Override
public void attributeAdded(ServletContextAttributeEvent event) {
// TODO Auto-generated method stub
}
@Override
public void attributeRemoved(ServletContextAttributeEvent event) {
// TODO Auto-generated method stub
}
@Override
public void attributeReplaced(ServletContextAttributeEvent event) {
// TODO Auto-generated method stub
}
@Override
public void contextDestroyed(ServletContextEvent sce) {
// TODO Auto-generated method stub
}
@Override
public void contextInitialized(ServletContextEvent sce) {
// TODO Auto-generated method stub
}
}
25 监听器Listener——ServletContext监听器
原文：https://www.cnblogs.com/Scorpicat/p/12396807.html