SpringApplication初始化

Posted 2020-11-04 wangdaijun

SpringApplication:
	private void initialize(Object[] sources) {
	if (sources != null && sources.length > 0) {
	this.sources.addAll(Arrays.asList(sources));
	}
	this.webEnvironment = deduceWebEnvironment();
	// 从spring.factories里读取所有 ApplicationContextInitializer，并记入 SpringApplication
	setInitializers((Collection) getSpringFactoriesInstances(
	ApplicationContextInitializer.class));
	// 从spring.factories里读取所有 ApplicationListener，并记入 SpringApplication
	setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));
	this.mainApplicationClass = deduceMainApplicationClass();
	}
	public ConfigurableApplicationContext run(String... args) {
	StopWatch stopWatch = new StopWatch();
	stopWatch.start();
	ConfigurableApplicationContext context = null;
	FailureAnalyzers analyzers = null;
	configureHeadlessProperty();
	// 从spring.factories里读取所有 SpringApplicationRunListener，监听springboot启动，参考：org.springframework.boot.context.event.EventPublishingRunListener
	SpringApplicationRunListeners listeners = getRunListeners(args);
	listeners.starting();
	try {
	ApplicationArguments applicationArguments = new DefaultApplicationArguments(
	args);
	ConfigurableEnvironment environment = prepareEnvironment(listeners,
	applicationArguments);
	Banner printedBanner = printBanner(environment);
	// web环境下默认的 ApplicationContext： org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext
	// 非web环境下默认的 ApplicationContext： org.springframework.context.annotation.AnnotationConfigApplicationContext
	context = createApplicationContext();
	analyzers = new FailureAnalyzers(context);
	// org.springframework.cloud.bootstrap.config.PropertySourceBootstrapProperties 会通过 ApplicationContextInitializer，准备 PropertySource
	// PropertySourceBootstrapProperties 收集 PropertySourceLocator 来获得PropertySource
	// 其中 org.springframework.cloud.config.client.ConfigServicePropertySourceLocator 是 Cloud Config Client 提供的 PropertySourceLocator
	prepareContext(context, environment, listeners, applicationArguments,
	printedBanner);
	// 调用 context.refresh
	refreshContext(context);
	afterRefresh(context, applicationArguments);
	listeners.finished(context, null);
	stopWatch.stop();
	if (this.logStartupInfo) {
	new StartupInfoLogger(this.mainApplicationClass)
	.logStarted(getApplicationLog(), stopWatch);
	}
	return context;
	}
	catch (Throwable ex) {
	handleRunFailure(context, listeners, analyzers, ex);
	throw new IllegalStateException(ex);
	}
	}