Spring Boot2 源码 run prepareContext方法 （四）

10、准备应用上下文

	private void prepareContext(ConfigurableApplicationContext context,
			ConfigurableEnvironment environment, SpringApplicationRunListeners listeners,
			ApplicationArguments applicationArguments, Banner printedBanner) {
                //设置环境参数
		context.setEnvironment(environment);
		postProcessApplicationContext(context);
                //所有ApplicationContextInitializer类 初始化
		applyInitializers(context);
                //contextPrepared监听事件
		listeners.contextPrepared(context);
		if (this.logStartupInfo) {
			logStartupInfo(context.getParent() == null);
			logStartupProfileInfo(context);
		}
		// 获取beanFactory 为下面注册单例bean做准备
		ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
		beanFactory.registerSingleton("springApplicationArguments", applicationArguments);
		if (printedBanner != null) {
			beanFactory.registerSingleton("springBootBanner", printedBanner);
		}
		if (beanFactory instanceof DefaultListableBeanFactory) {
			((DefaultListableBeanFactory) beanFactory)
					.setAllowBeanDefinitionOverriding(this.allowBeanDefinitionOverriding);
		}
		// Load the sources
		Set<Object> sources = getAllSources();
		Assert.notEmpty(sources, "Sources must not be empty");
		load(context, sources.toArray(new Object[0]));
                //contextLoaded监听事件
		listeners.contextLoaded(context);
	}

public void setEnvironment(ConfigurableEnvironment environment) {
    // 设置context的environment
    super.setEnvironment(environment);    
    // 实例化context的reader属性的environment属性        
    this.reader.setEnvironment(environment);  
    // 设置context的scanner属性的environment属性  
    this.scanner.setEnvironment(environment);    
}

this.beanNameGenerator和this.resourceLoader为空应该是扩展用的

protected void postProcessApplicationContext(ConfigurableApplicationContext context) {
		if (this.beanNameGenerator != null) {
			context.getBeanFactory().registerSingleton(
					AnnotationConfigUtils.CONFIGURATION_BEAN_NAME_GENERATOR,
					this.beanNameGenerator);
		}
		if (this.resourceLoader != null) {
			if (context instanceof GenericApplicationContext) {
				((GenericApplicationContext) context)
						.setResourceLoader(this.resourceLoader);
			}
			if (context instanceof DefaultResourceLoader) {
				((DefaultResourceLoader) context)
						.setClassLoader(this.resourceLoader.getClassLoader());
			}
		}
	}

初始化ApplicationContextInitializer，执行所有ApplicationContextInitializer类的initialize方法，赋值在SpringApplication的构造方法中

org.springframework.boot.context.config.DelegatingApplicationContextInitializer@f440ae7, org.springframework.boot.autoconfigure.SharedMetadataReaderFactoryContextInitializer@5351a81e, org.springframework.boot.context.ContextIdApplicationContextInitializer@38bd9799, org.springframework.boot.context.ConfigurationWarningsApplicationContextInitializer@2884f688, org.springframework.boot.web.context.ServerPortInfoApplicationContextInitializer@7b8c24d, org.springframework.boot.autoconfigure.logging.ConditionEvaluationReportLoggingListener@59f79bfc, org.springframework.boot.devtools.restart.RestartScopeInitializer@d22de04

	protected void applyInitializers(ConfigurableApplicationContext context) {
		for (ApplicationContextInitializer initializer : getInitializers()) {
			Class<?> requiredType = GenericTypeResolver.resolveTypeArgument(
					initializer.getClass(), ApplicationContextInitializer.class);
			Assert.isInstanceOf(requiredType, context, "Unable to call initializer.");
			initializer.initialize(context);
		}
	}

 

 context.getBeanFactory();获取beanFactory ，赋值在GenericApplicationContext类中，此类是AnnotationConfigServletWebServerApplicationContext父类

	public GenericApplicationContext() {
		this.beanFactory = new DefaultListableBeanFactory();
	}

重点关注一下load方法，加载启动类到spring容器

一直跟进load方法会找到AnnotatedBeanDefinitionReader类的doRegisterBean方法负责注册启动类，注册通俗上来讲将启动类存入DefaultListableBeanFactory类的this.beanDefinitionMap（ConcurrentHashMap）变量中。

	<T> void doRegisterBean(Class<T> annotatedClass, @Nullable Supplier<T> instanceSupplier, @Nullable String name,
			@Nullable Class<? extends Annotation>[] qualifiers, BeanDefinitionCustomizer... definitionCustomizers) {

		AnnotatedGenericBeanDefinition abd = new AnnotatedGenericBeanDefinition(annotatedClass);
		if (this.conditionEvaluator.shouldSkip(abd.getMetadata())) {
			return;
		}

		abd.setInstanceSupplier(instanceSupplier);
		ScopeMetadata scopeMetadata = this.scopeMetadataResolver.resolveScopeMetadata(abd);
		abd.setScope(scopeMetadata.getScopeName());
		String beanName = (name != null ? name : this.beanNameGenerator.generateBeanName(abd, this.registry));

		AnnotationConfigUtils.processCommonDefinitionAnnotations(abd);
		if (qualifiers != null) {
			for (Class<? extends Annotation> qualifier : qualifiers) {
				if (Primary.class == qualifier) {
					abd.setPrimary(true);
				}
				else if (Lazy.class == qualifier) {
					abd.setLazyInit(true);
				}
				else {
					abd.addQualifier(new AutowireCandidateQualifier(qualifier));
				}
			}
		}
		for (BeanDefinitionCustomizer customizer : definitionCustomizers) {
			customizer.customize(abd);
		}

		BeanDefinitionHolder definitionHolder = new BeanDefinitionHolder(abd, beanName);
		definitionHolder = AnnotationConfigUtils.applyScopedProxyMode(scopeMetadata, definitionHolder, this.registry);
		BeanDefinitionReaderUtils.registerBeanDefinition(definitionHolder, this.registry);
	}