springboot实战笔记(七 )----springboot整合Listener

约定不等于承诺〃 2022-01-26 07:51 344阅读 0赞

### 一 前言 ###

在以往的web.xml方式中，我们是通过以下形式进行配置Listener的：

<listener>
     	<listener-class>com.bjsxt.listener.FirstListener</listener-class>
    </listener>

但是在springboot整合Listener可以通过以下的两种方式，

*  通过注解扫描完成 Listener 组件的注册
 *  通过方法完成 Listener 组件的注册

pom.xml：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.10.RELEASE</version>
      </parent>
      <groupId>com.bjsxt</groupId>
      <artifactId>04-spring-boot-Listener</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      
      
      <properties>
      	<java.version>1.7</java.version>
      </properties>
      
      <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>
    </project>

### 二 注解扫描方式 ###

1.编写 Listener类

package com.bjsxt.listener;
    
    import javax.servlet.ServletContextEvent;
    import javax.servlet.ServletContextListener;
    import javax.servlet.annotation.WebListener;
    /**
     * springBoot整合Listener
     */
    @WebListener
    public class FirstListener implements ServletContextListener {
    
    	@Override
    	public void contextDestroyed(ServletContextEvent arg0) {
    		// TODO Auto-generated method stub
    
    	}
    
    	@Override
    	public void contextInitialized(ServletContextEvent arg0) {
    		System.out.println("Listener...init......");
    
    	}
    
    }

2.编写启动类

package com.bjsxt;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.boot.web.servlet.ServletComponentScan;
    
    /**
     * springBoot整合Listener方式一
     */
    @SpringBootApplication
    @ServletComponentScan
    public class App {
    
    	public static void main(String[] args) {
    		SpringApplication.run(App.class, args);
    	}
    
    }

### 三 方法方式 ###

1.编写Listener类

package com.bjsxt.listener;
    
    import javax.servlet.ServletContextEvent;
    import javax.servlet.ServletContextListener;
    /**
     * springBoot整合Listener方式二。
     *
     *
     */
    public class SecondListener implements ServletContextListener {
    
    	@Override
    	public void contextDestroyed(ServletContextEvent arg0) {
    		// TODO Auto-generated method stub
    	}
    
    	@Override
    	public void contextInitialized(ServletContextEvent arg0) {
    		System.out.println("SecondListener..init.....");
    	}
    
    }

2.编写启动类

package com.bjsxt;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.boot.web.servlet.ServletListenerRegistrationBean;
    import org.springframework.context.annotation.Bean;
    
    import com.bjsxt.listener.SecondListener;
    
    /**
     * SpringBoot整合Listener方式二
     *
     *
     */
    @SpringBootApplication
    public class App2 {
    
    	public static void main(String[] args) {
    		SpringApplication.run(App2.class, args);
    
    	}
    	/**
    	 * 注册listener
    	 */
    	@Bean
    	public ServletListenerRegistrationBean<SecondListener> getServletListenerRegistrationBean(){
    		ServletListenerRegistrationBean<SecondListener> bean= new ServletListenerRegistrationBean<SecondListener>(new SecondListener());
    		return bean;
    	}
    }