prepareContext

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prepareContext

  • 步骤:
    • 设置environment
    • 后置处理ApplicationContext
    • 执行Initializers
    • 发布contextPrepared事件
    • 日志
    • 注册单例bean
    • 加载启动类
    • 发布contextLoaded事件
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private void prepareContext(ConfigurableApplicationContext context, ConfigurableEnvironment environment, SpringApplicationRunListeners listeners, ApplicationArguments applicationArguments, Banner printedBanner) {
    //设置上下文环境
    context.setEnvironment(environment);
    //ApplicationContext的后置处理
    postProcessApplicationContext(context);
    //执行Initializers
    applyInitializers(context);
    //发布contextPrepared事件
    listeners.contextPrepared(context);
    //日志
    if (this.logStartupInfo) {
        logStartupInfo(context.getParent() == null);
        logStartupProfileInfo(context);
    }
    // Add boot specific singleton beans 注册单例bean
    ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
    beanFactory.registerSingleton("springApplicationArguments", applicationArguments);
    if (printedBanner != null) {
        beanFactory.registerSingleton("springBootBanner", printedBanner);
    }
    if (beanFactory instanceof DefaultListableBeanFactory) {
        ((DefaultListableBeanFactory) beanFactory)
        .setAllowBeanDefinitionOverriding(this.allowBeanDefinitionOverriding);
    }
    if (this.lazyInitialization) {
        context.addBeanFactoryPostProcessor(new LazyInitializationBeanFactoryPostProcessor());
    }
    // Load the sources
    Set<Object> sources = getAllSources();
    Assert.notEmpty(sources, "Sources must not be empty");
    //初始化bean加载器,并加载bean到应用上下文
    load(context, sources.toArray(new Object[0]));
    //发布contextLoaded事件
    listeners.contextLoaded(context);
}

设置上下文环境,以AnnotationConfigServletWebServerApplicationContext为例

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@Override
public void setEnvironment(ConfigurableEnvironment environment) {
    //显式调用父类AbstractApplicationContext的setEnvironment方法
    super.setEnvironment(environment);
    //调用AnnotatedBeanDefinitionReader#setEnvironment()方法
    this.reader.setEnvironment(environment);
    //ClassPathBeanDefinitionScanner调用父类的setEnvironment方法
    this.scanner.setEnvironment(environment);
}

后置处理

  • 设置ApplicationContext的beanNameGenerator
  • 设置ApplicationContext的resourceLoader和classLoader
  • 设置ApplicationContext的类型转换Service
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protected void postProcessApplicationContext(ConfigurableApplicationContext context) {
    //设置ApplicationContext的beanNameGenerator
    if (this.beanNameGenerator != null) {
        context.getBeanFactory().registerSingleton(AnnotationConfigUtils.CONFIGURATION_BEAN_NAME_GENERATOR, this.beanNameGenerator);
    }
    //设置ApplicationContext的resourceLoader和classLoader
    if (this.resourceLoader != null) {
        if (context instanceof GenericApplicationContext) {
            ((GenericApplicationContext) context).setResourceLoader(this.resourceLoader);
        }
        if (context instanceof DefaultResourceLoader) {
            ((DefaultResourceLoader) context).setClassLoader(this.resourceLoader.getClassLoader());
        }
    }
    //设置ApplicationContext的类型转换Service
    if (this.addConversionService) {
        context.getBeanFactory().setConversionService(ApplicationConversionService.getSharedInstance());
    }
}

…
prepareContext()这一步的主要作用是为下面刷新applicationContext做准备
参考1