springboot在启动时做点什么

ldj2020

已于 2023-07-13 16:13:13 修改

阅读量126

点赞数

文章标签： java 开发语言

于 2023-06-21 17:15:37 首次发布

本文链接：https://blog.youkuaiyun.com/dj1955/article/details/131331456

版权

文章详细阐述了在SpringBoot应用中，ContextRefreshedEvent和ApplicationReadyEvent两个事件的区别。ContextRefreshedEvent通常在容器初始化完成后触发，可能因容器类型而触发多次，而ApplicationReadyEvent则在所有初始izers和runners执行完毕，应用准备就绪时触发，只会触发一次。文中还展示了如何实现ApplicationListener来监听这两个事件，并给出了不同顺序的CommandLineRunner和ApplicationRunner的执行示例。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

ContextRefreshedEvent和ApplicationReadyEvent区别？

ApplicationReadyEvent 容器启动只会触发一次；

ContextRefreshedEvent 如果容器是AbstractRefreshableApplicationContext的子类可能被触发多次；SpringBoot默认启动的容器GenericWebApplicationContext，因为它不是AbstractRefreshableApplicationContext的子类，也只会触发一次）

ContextRefreshedEvent的调用在ApplicationReadyEvent之前被调用：

@Component
public class ApplicationInitListener implements ApplicationListener<ContextRefreshedEvent> {

    @Override
    public void onApplicationEvent(ContextRefreshedEvent contextRefreshedEvent) {
        System.out.println("ContextRefreshedEvent.....容器初始化完成");
    }
}


@Component
public class ApplicationReadyEventListener implements ApplicationListener<ApplicationReadyEvent> {

    @Override
    public void onApplicationEvent(ApplicationReadyEvent applicationReadyEvent) {
        System.out.println("ApplicationReadyEvent.....");
    }
}

import java.util.Arrays;

/**
 * @Author: ldj
 * @Date: 2023/06/21/16:59
 * @Description:
 */
@Order(-1)
@Component
public class Test3Runner implements ApplicationRunner {

    @Override
    public void run(ApplicationArguments args) throws Exception {
        System.out.println("Test3Runner执行一次....." + Arrays.toString(args.getSourceArgs()));
    }
}


@Order(1)
@Component
public class TestOneRunner implements CommandLineRunner {

    @Override
    public void run(String... args) throws Exception {
        System.out.println("TestOneRunner执行一次.....");
    }
}


@Order(0)
@Component
public class TestTowRunner implements CommandLineRunner {

    @Override
    public void run(String... args) throws Exception {
        System.out.println("TestTowRunner执行一次.....");
    }
}