SpringBean 元信息

元信息的配置

• 通过资源的方式配置，如： XML、 Properties、Groovy
• 通过注解配置 ： @Bean
• 通过API配置 ：BeanDefinitionBuilder / GenericBeanDefinition

元信息的读取

1) Get beanDefinitionRegistry for registry beanDefinitions.
2) Get ResourceLoader
3) Get ClassLoader.

• 读取通过资源方式配置，如：XmlBeanDefinitionReader、PropertiesBeanDefinitionReader、GroovyBeanDefinitionReader
• 读取注解配置的Bean：AnnotatedBeanDefinitionReader

DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
AnnotatedBeanDefinitionReader reader = new AnnotatedBeanDefinitionReader(beanFactory);
reader.register(Main.class);

元信息的解析

图片版本的看不太清，整理一份文字版本的层级关系，除BeanDefinitionParser是顶层抽象接口外，其余Parser都是类或者抽象类。

• BeanDefinitionParser
  • SpringConfiguredBeanDefinitionParser
  • AnnotationDrivenCacheBeanDefinitionParser
  • ScriptingDefaultsParser
  • ComponentScanBeanDefinitionParser
  • AnnotationConfigBeanDefinitionParser
  • AspectJAutoProxyBeanDewfinitionParser
  • SpringConfiguredBeanDefinitionParser
  • ConfigBeanDefinitionParser
  • AnnotationDrivenBeanDefinitionParser
  • AbstractBeanDefinitionParser
    • MBeanExportBeanDefinitionParser
    • MBeanServiceBeanDefinitionParser
    • ScriptBeanDefinitionParser
    • AbstractSingleBeanDefinitionParser
      • ExecutorBeanDefinitionParser
      • SchedulerBeanDefinitionParser
      • SetBeanDefinitionParser
      • AbstractPropertyLoadingBeanDefinitionParser
      • LoadTimeWeaverBeanDefinitionParser
      • CacheAdviceParser
      • ListBeanDefinitionParser
      • ScheduledTasksBeanDefinitionParser
      • MapBeanDefinitionParser
      • PropertiesBeanDefinitionParser
      • PropertyPathBeanDefinitionParser
      • AbstractSimpleBeanDefinitionParser
        • ConstantBeanDefinitionParser
        • AbstractJndiLocatingBeanDefinitionParser
          • JndiLookupBeanDefinitionParser
          • LocalStatelessSessionBeanDefinitionParser
          • RemoteStatelessSessionBeanDefinitionParser

SpringBean 注册

@Override
  public void registerBeanDefinition(String beanName, BeanDefinition beanDefinition)
      throws BeanDefinitionStoreException {

    BeanDefinition existingDefinition = this.beanDefinitionMap.get(beanName);
      this.beanDefinitionMap.put(beanName, beanDefinition);
    }
    else {
      if (hasBeanCreationStarted()) {
        // Cannot modify startup-time collection elements anymore (for stable iteration)
        synchronized (this.beanDefinitionMap) {
          this.beanDefinitionMap.put(beanName, beanDefinition);
          List<String> updatedDefinitions = new ArrayList<>(this.beanDefinitionNames.size() + 1);
          updatedDefinitions.addAll(this.beanDefinitionNames);
          updatedDefinitions.add(beanName);
          this.beanDefinitionNames = updatedDefinitions;
          removeManualSingletonName(beanName);
        }
      }
      else {
        // Still in startup registration phase
        this.beanDefinitionMap.put(beanName, beanDefinition);
        this.beanDefinitionNames.add(beanName);
        removeManualSingletonName(beanName);
      }
      this.frozenBeanDefinitionNames = null;
    }

    if (existingDefinition != null || containsSingleton(beanName)) {
      resetBeanDefinition(beanName);
    }
  }

Spring BeanDefinition 合并阶段

GenericBeanDefinition -> RootBeanDefinition

Spring Bean Class 加载阶段

BeanDefinition 中定义的Class名称加载具体的Class类。

ClassLoader 类加载
Java Security 安全控制
ConfigurableBeanFactory 临时 ClassLoader

Spring Bean 实例化
实例化前：
InstantiationAwareBeanProcessor.postProcessorBeforeInstantiation()
提前生成一些代理对象，替换掉默认的springIOC的实现内容。
实例化
传统实例化方式
+ 实例化策略 InstantiationStrategy

构造器依赖注入（根据类型来注入）

实例化后
InstantiationAwareBeanProcessor.postProcessorAfterInstantiation()

Spring Bean 属性赋值前阶段

Bean的属性值元信息： PropertyValues
构造器参数值：ConstructorValues

Bean属性赋值前回调
<= 5.0 InstantiationAwareBeanPostProcessor#postProcessorPropertyValues();
>= 5.1 InstantiationAwareBeanPostProcessor#postProcessorProperties();

Spring Bean Aware 接口回调阶段

Aware接口是一个标志接口，并没有提供任何实现。
BeanNameAware
BeanClassLoaderAware
BeanFactoryAware
EnvironmentAware
EmbeddedValueResolverAware
ApplicationEventPublisherAware
MessageSourceAware
ApplicationContextAware

Spring Bean 初始化

初始化前
BeanPostProcessor#postProcessorBeforeInitialization
初始化
@PostConstructor
AfterPropertiesSet
init-method
初始化后
BeanPostProcessor#postProcessAfterInitialization
初始化完成
SmartinitializingSingleton#afterSingletonsInstanted

AbstractAutowireCapableBeanFactory

/**
 * Initialize the given bean instance, applying factory callbacks
 * as well as init methods and bean post processors.
 * <p>Called from {@link #createBean} for traditionally defined beans,
 * and from {@link #initializeBean} for existing bean instances.
 * @param beanName the bean name in the factory (for debugging purposes)
 * @param bean the new bean instance we may need to initialize
 * @param mbd the bean definition that the bean was created with
 * (can also be {@code null}, if given an existing bean instance)
 * @return the initialized bean instance (potentially wrapped)
 * @see BeanNameAware
 * @see BeanClassLoaderAware
 * @see BeanFactoryAware
 * @see #applyBeanPostProcessorsBeforeInitialization
 * @see #invokeInitMethods
 * @see #applyBeanPostProcessorsAfterInitialization
 */
protected Object initializeBean(final String beanName, final Object bean, @Nullable RootBeanDefinition mbd) {
  if (System.getSecurityManager() != null) {
    AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
      invokeAwareMethods(beanName, bean);
      return null;
    }, getAccessControlContext());
  }
  else {
    invokeAwareMethods(beanName, bean);
  }

  Object wrappedBean = bean;
  if (mbd == null || !mbd.isSynthetic()) {
    wrappedBean = applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName);
  }

  try {
    invokeInitMethods(beanName, wrappedBean, mbd);
  }
  catch (Throwable ex) {
    throw new BeanCreationException(
        (mbd != null ? mbd.getResourceDescription() : null),
        beanName, "Invocation of init method failed", ex);
  }
  if (mbd == null || !mbd.isSynthetic()) {
    wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);
  }

  return wrappedBean;
}

Spring Bean 销毁
销毁前
DestructionAwareBeanPostProcessor#postProcessorBeforeDestruction
销毁
@PreDestroy
实现DisposableBean接口的destroy方法
自定义销毁方法
垃圾回收
关闭Spring 容器
执行GC
SpringBean 覆盖finalize()方法被回调