[Java知识库]spring-refresh-prepareBeanFactory

为BeanFactory做一些准备工作

1.设置beanFactory 的类加载器；
2.设置EL表达式解析器（Bean创建完成填充属性时使用）和属性注册解析器
3.添加BeanPostProcessor
4.设置各种Aware接口的实现类为忽略自动装配
5.设置自动装配的类（BeanFactory，ResourceLoader，ApplicationEventPublisher，ApplicationContext）
6.如果BeanFactory中存在loadTimeWeaver的bean，那么需要添加动态织入功能
7.注册各种可用组件（environment，systemProperties，systemEnvironment）

protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
    //设置beanFactory的类加载器
    beanFactory.setBeanClassLoader(getClassLoader());
    //添加Spring的EL表达式解析器。
    if (!shouldIgnoreSpel) {
        beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
    }

    //为beanFactory增加了一个默认的propertyEditor（属性编辑器）
    beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));

    //添加到后置处理器,创建的 ApplicationContextAwareProcessor入参为当前 ApplicationContext
    beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));

    //忽略自动装配,如果注入EnvironmentAware这个bd会注不进来
    beanFactory.ignoreDependencyInterface(EnvironmentAware.class);
    beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class);
    beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
    beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
    beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
    beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);
    beanFactory.ignoreDependencyInterface(ApplicationStartup.class);

    //注册自动装配的类
    beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);
    beanFactory.registerResolvableDependency(ResourceLoader.class, this);
    beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);
    beanFactory.registerResolvableDependency(ApplicationContext.class, this);

    //添加后置处理器ApplicationListenerDetector
    beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));

   
    // 是否需要类加载期间织入  增加Aspectj的支持
    if (!IN_NATIVE_IMAGE && beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
        beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
        beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
    }

  
    // 注册其他的 bean
    if (!beanFactory.containsLocalBean(ENVIRONMENT_BEAN_NAME)) {
        beanFactory.registerSingleton(ENVIRONMENT_BEAN_NAME, getEnvironment());
    }
    if (!beanFactory.containsLocalBean(SYSTEM_PROPERTIES_BEAN_NAME)) {
        beanFactory.registerSingleton(SYSTEM_PROPERTIES_BEAN_NAME, getEnvironment().getSystemProperties());
    }
    if (!beanFactory.containsLocalBean(SYSTEM_ENVIRONMENT_BEAN_NAME)) {
        beanFactory.registerSingleton(SYSTEM_ENVIRONMENT_BEAN_NAME, getEnvironment().getSystemEnvironment());
    }
    if (!beanFactory.containsLocalBean(APPLICATION_STARTUP_BEAN_NAME)) {
        beanFactory.registerSingleton(APPLICATION_STARTUP_BEAN_NAME, getApplicationStartup());
    }
}

上面有添加三个BeanPostProcessor分别是：

1. ApplicationListenerDetector 可以看这个文章跳转
2. ApplicationContextAwareProcessor 可以查看跳转
3. LoadTimeWeaverAwareProcessor 可以查看 跳转