7_1.springboot2.x启动配置原理_1.创建SpringApplication对象

环境准备

springboot2.1.9、idea2019、

pom.xml

解析

几个重要的事件回调机制
配置在META-INF/spring.factories
ApplicationContextInitializer
SpringApplicationRunListener

只需要放在ioc容器中
ApplicationRunner
CommandLineRunner

在主配置类打断点进行调试

可见springboot应用程序分为两步：1、创建SpringApplication对象；2、运行run方法

创建SpringApplication对象

	public SpringApplication(ResourceLoader resourceLoader, Class<?>... primarySources) {
		this.resourceLoader = resourceLoader;
        //判断主配置类不能为空
		Assert.notNull(primarySources, "PrimarySources must not be null");
        //保存主配置类
		this.primarySources = new LinkedHashSet<>(Arrays.asList(primarySources));
        //判断当前是否一个web应用
		this.webApplicationType = WebApplicationType.deduceFromClasspath();
//从类路径下找到META‐INF/spring.factories配置的所有ApplicationContextInitializer；然后保存
		setInitializers((Collection) getSpringFactoriesInstances(ApplicationContextInitializer.class));
//从类路径下找到ETA‐INF/spring.factories配置的所有ApplicationListener
		setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));
//从多个配置类中找到有main方法的主配置类
		this.mainApplicationClass = deduceMainApplicationClass();
	}

setInitializers((Collection) getSpringFactoriesInstances(ApplicationContextInitializer.class));

setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));

查看已创建的SpringApplication对象：

之后运行run方法。。