SpringBoot中的ServletContextListener接口实现类

 Spring中ContextLoaderListener类实现了ServletContextListener接口

可以看到有

 在SpringBoot中用来初始化WebApplicationContext。

/*** Initialize the root web application context.*/
&＃64;Override
public void contextInitialized(ServletContextEvent event) {initWebApplicationContext(event.getServletContext());
}

实现这个接口还能处理一些启动前和启动后&＃xff0c;或者销毁后的一些事情。例如

用来将数据库中数据缓存到redis中


import com.rongsoft.eurekacenter.eurekacenter.config.Person;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.cloud.loadbalancer.core.LoadBalancerServiceInstanceCOOKIETransformer;
import org.springframework.context.ApplicationContext;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
import java.util.Enumeration;/*** 可以实现ContextLoaderListener 也可以实现ServletContextListener&＃xff0c;结果一致* 需要添加&＃64;ServletComponentScan 注解*/
&＃64;Slf4j
&＃64;Component
&＃64;WebListener
public class SpringServletContextListener implements ServletContextListener {// 这个autowired无效&＃xff0c;不知道为何&＃64;Autowired&＃64;Qualifier("stringRedisTemplate")private StringRedisTemplate stringRedisTemplate;&＃64;Overridepublic void contextInitialized(ServletContextEvent event) {ServletContext servletContext &＃61; event.getServletContext();Enumeration enumeration &＃61; servletContext.getAttributeNames();while (enumeration.hasMoreElements()){String element &＃61; enumeration.nextElement();log.info("-----ContextLoaderListener-----"&＃43;element);if (WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE.equals(element)){// 这个就是ApplicationContextApplicationContext context &＃61; (ApplicationContext) servletContext.getAttribute(element);stringRedisTemplate &＃61; context.getBean(StringRedisTemplate.class);log.info("从ServletContext获取ApplicationContext&＃xff1a;"&＃43;context.getBean(Person.class));log.info("从ServletContext获取ApplicationContext&＃xff1a;"&＃43;stringRedisTemplate);String name &＃61; (String) stringRedisTemplate.opsForValue().get("name");log.info("从redis获取数据&＃xff1a;RedisTemplate:"&＃43;name);}}// 通过servlet获取ApplicationContextApplicationContext applicationContext &＃61; WebApplicationContextUtils.getWebApplicationContext(servletContext);log.info("-----ContextLoaderListener---"&＃43;applicationContext.getBean(Person.class));log.info("-----ContextLoaderListener---"&＃43;applicationContext.getBean(LoadBalancerServiceInstanceCOOKIETransformer.class));log.info("-----ContextLoaderListener---"&＃43;applicationContext.getBean(StringRedisTemplate.class));stringRedisTemplate &＃61; applicationContext.getBean(StringRedisTemplate.class);Enumeration enumeration1 &＃61; servletContext.getAttributeNames();while (enumeration1.hasMoreElements()){log.info("-----ContextLoaderListener-----"&＃43;enumeration1.nextElement());}String name &＃61; (String) stringRedisTemplate.opsForValue().get("name");log.info("从redis获取数据&＃xff1a;RedisTemplate:"&＃43;name);}&＃64;Overridepublic void contextDestroyed(ServletContextEvent event) {log.info("-----销毁---");}
}


参数如下

spring.redis.host&＃61;127.0.0.1
spring.redis.port&＃61;6379
spring.redis.lettuce.pool.max-idle&＃61;8
spring.redis.lettuce.pool.max-active&＃61;8
spring.redis.lettuce.pool.max-wait&＃61;-1ms
spring.redis.lettuce.pool.min-idle&＃61;0
spring.redis.lettuce.shutdown-timeout&＃61;100ms

 具体使用可以参照&＃xff1a;

ServletContextListener的作用 - 星朝 - 博客园

SpringBoot集成Redis缓存并实现初始化用户数据到Redis缓存_码出精彩-CSDN博客_redis缓存初始化