详解springboot整合Listener的两种方式

package cn.bl;
import org.spring work.boot.SpringApplication;
import org.spring work.boot.autoconfigure.SpringBootApplication;
import org.spring work.boot.web.servlet.ServletComponentScan;
@SpringBootApplication
@ServletComponentScan
public class App {
 public static void main(String[] args) {
 SpringApplication.run(App.class, args);
 }
}

package cn.bl.listener;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
@WebListener
public class FirstListener implements ServletContextListener{
 @Override
 public void contextInitialized(ServletContextEvent sce) {
 System.out.println(\"init .. \");
 }
 @Override
 public void contextDestroyed(ServletContextEvent sce) {
 System.out.println(\"desroyed .. \");
 }
}

package cn.bl.listener;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
public class SecondListener implements ServletContextListener{
 @Override
 public void contextInitialized(ServletContextEvent sce) {
 System.out.println(\"second servletListener init .. \");
 }
 @Override
 public void contextDestroyed(ServletContextEvent sce) {
 System.out.println(\"second servletListener destroy .. \");
 }
}

package cn.bl;


import org.spring work.boot.SpringApplication;
import org.spring work.boot.autoconfigure.SpringBootApplication;
import org.spring work.boot.web.servlet.ServletListenerRegistrationBean;
import org.spring work.context.annotation.Bean;
import cn.bl.listener.SecondListener;
@SpringBootApplication
public class App2 {
 public static void main(String[] args) {
 SpringApplication.run(App2.class, args);
 }
 @Bean
 public ServletListenerRegistrationBean<SecondListener>getBean(){
 ServletListenerRegistrationBean<SecondListener>bean = new ServletListenerRegistrationBean<>(new SecondListener());
 return bean;
 }
}