javaWeb监听器Listener -自定义监听器类实现

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
public class MyServletContextListener implements ServletContextListener {
  @Override
  public void contextDestroyed(ServletContextEvent arg0) {
    System.out.println("****************ServletContext 对象销毁了****************");
  }
  @Override
  public void contextInitialized(ServletContextEvent arg0) {
    System.out.println("****************ServletContext 对象创建了****************");
  }
}

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns="http://xmlns.jcp.org/xml/ns/javaee"
  xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
  id="WebApp_ID" version="3.1">
  <display-name>day_20220909</display-name>
  <listener>
    <listener-class>com.heima.MyServletContextListener</listener-class>
  </listener>
</web-app>

信息: Initializing ProtocolHandler ["http-apr-8080"]
九月 09, 2022 4:02:11 下午 org.apache.coyote.AbstractProtocol init
信息: Initializing ProtocolHandler ["ajp-apr-8009"]
九月 09, 2022 4:02:11 下午 org.apache.catalina.startup.Catalina load
信息: Initialization processed in 1533 ms
九月 09, 2022 4:02:11 下午 org.apache.catalina.core.StandardService startInternal
信息: Starting service Catalina
九月 09, 2022 4:02:11 下午 org.apache.catalina.core.StandardEngine startInternal
信息: Starting Servlet Engine: Apache Tomcat/8.0.53
九月 09, 2022 4:02:12 下午 org.apache.catalina.util.SessionIdGeneratorBase createSecureRandom
警告: Creation of SecureRandom instance for session ID generation using [SHA1PRNG] took [405] milliseconds.
****************ServletContext 对象创建了****************
九月 09, 2022 4:02:12 下午 org.apache.coyote.AbstractProtocol start
信息: Starting ProtocolHandler ["http-apr-8080"]
九月 09, 2022 4:02:12 下午 org.apache.coyote.AbstractProtocol start
信息: Starting ProtocolHandler ["ajp-apr-8009"]
九月 09, 2022 4:02:12 下午 org.apache.catalina.startup.Catalina start
信息: Server startup in 812 ms