SpringBoot 启动过程

左手的ㄟ右手 2023-01-14 01:35 78阅读 0赞

spring boot 的启动是由一个main方法开始，创建一个SpringApplicationBuilder对象，通过该Builder对象执行SpringApplication对象的run()方法， 以下是SpringApplication.run(String…)的执行过程：

new SpringApplication() ## 从Factories中获取ApplicationContextInitializer和ApplicationListener，找到main class
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    SpringApplication#run() ## spring boot启动的逻辑都在这个方法中
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    	getRunListeners() ## 从Factories中获取SpringApplicationRunListener
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    	prepareEnvironment(SpringApplicationRunListeners, ApplicationArguments) ## 1､配置environment的PropertySources和Profiles， 2､执行SpringApplicationRunListener#environmentPrepared(ConfigurableEnvironment)， 
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    	printBanner(ConfigurableEnvironment) ## 打印banner
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    	createApplicationContext() ## 创建ApplicationContext
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    	prepareContext(ConfigurableApplicationContext, ConfigurableEnvironment, SpringApplicationRunListeners, ApplicationArguments, Banner) ## 准备上下文属性和动作; 1､将environment放入context； ...
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    		postProcessApplicationContext(ConfigurableApplicationContext) ## 设置beanNameGenerator、resourceLoader、ConversionService
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    		applyInitializers(ConfigurableApplicationContext) ## 执行ApplicationContextInitializer#initialize(ConfigurableApplicationContext)
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    		SpringApplicationRunListeners#contextPrepared(ConfigurableApplicationContext) ## 执行SpringApplicationRunListeners#contextPrepared()
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    		load(ApplicationContext, Object[]) ## 加载spring boot sources，封装为BeanDefinition注册到BeanDefinitionRegistry中， 例如main class
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    		SpringApplicationRunListeners.contextLoaded(ConfigurableApplicationContext) ## 执行SpringApplicationRunListeners.contextLoaded()
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    	refreshContext(ConfigurableApplicationContext) ## 执行ConfigurableApplicationContext#refresh()方法，注册shutdown hook
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    	SpringApplicationRunListeners.started(ConfigurableApplicationContext) ## 执行SpringApplicationRunListener#started()
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    	callRunners(ApplicationContext, ApplicationArguments) ## 执行ApplicationRunner和CommandLineRunner的run(String...)方法
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    	SpringApplicationRunListeners.running(ConfigurableApplicationContext) ## 执行SpringApplicationRunListener#running()