Spring Core 2

getBean

所有的getBean方法最终底层都会调用doGetBean方法

protected <T> T doGetBean(final String name,final Class<T> requiredType,
final Object[] args, boolean typeCheckOnly) throws BeansException

transformedBeanName

去掉beanName所有的&前缀，通过aliasMap获取到最终的beanName

getSingleton 获取提前注册的单例bean🙈

protected Object getSingleton(String beanName, boolean allowEarlyReference){
        // 先在缓存中获取
        Object singletonObject = this.singletonObjects.get(beanName);
       // 缓存中不存在这个bean并且这个bean正在创建中
        if (singletonObject == null && isSingletonCurrentlyInCreation(beanName)) {
            synchronized (this.singletonObjects) {
                // 从提前实例化的bean中获取
                singletonObject = this.earlySingletonObjects.get(beanName);
                // bean不存在并且运行提前引用未实例化完成的bean
                if (singletonObject == null && allowEarlyReference) {
                    // 从提前暴露出来的bean中获取引用
                    ObjectFactory<?> singletonFactory = this.singletonFactories.get(beanName);
                    if (singletonFactory != null) {
                        // 实例化提前暴露的bean🙈
                        singletonObject = singletonFactory.getObject();
                        // 将实例化的结果放入提前实例化的earlySingletonObjects中
                        this.earlySingletonObjects.put(beanName, singletonObject);
                        // 从提前暴露出来的bean引用中去掉
                        this.singletonFactories.remove(beanName);
                    }
                }
            }
        }
        return singletonObject;
    }

缓存中未获取到bean：
原型bean判断是否有有循环依赖（当前需要获取的bean正在创建中）
如果存在父beanFactory容器，从父容器中获取

typeCheckOnly为false，标记当前bean为已创建，加入到alreadyCreated中，并从mergedBeanDefinitions从清除该bean
获取当前beanDefinition，获取依赖列表，并维护到dependentBeanMap和dependenciesForBeanMap中，实例化依赖的bean
单例bean:
getSingleton()
singletonObjects中获取
beforeSingletonCreation：
加入正在创建列表singletonsCurrentlyInCreation中
ObjectFactory创建bean
createBean:
<重点重点重重点>
afterSingletonCreation：
从正在创建列表singletonsCurrentlyInCreation中删除
addSingleton：维护实例化好的bean实例

protected void addSingleton(String beanName, Object singletonObject) {
    synchronized (this.singletonObjects) {
        this.singletonObjects.put(beanName, singletonObject);
        this.singletonFactories.remove(beanName);
        this.earlySingletonObjects.remove(beanName);
        this.registeredSingletons.add(beanName);
    }
}

原型bean：
beforePrototypeCreation
加入正在创建列表prototypesCurrentlyInCreation
createBean:
<重点重点重重点>
afterPrototypeCreation
从正在创建列表prototypesCurrentlyInCreation中删除
其他scope：🙈
根据scope封装不同的获取策略

createBean

resolveBeanClass解析beanClass
BeanPostProcessor=》InstantiationAwareBeanPostProcessor
实例化前的扩展点：postProcessBeforeInstantiation、postProcessAfterInitialization🚩
doCreateBean：
createBeanInstance创建bean实例
instantiateUsingFactoryMethod factory-method
autowireConstructor 构造器 SmartInstantiationAwareBeanPostProcessor#determineCandidateConstructors
instantiateBean 实例化bean
默认构造函数构造
MergedBeanDefinitionPostProcessor#postProcessMergedBeanDefinition
是否运行提前暴露：earlySingletonExposure

protected void addSingletonFactory(String beanName, ObjectFactory<?> singletonFactory) {
  Assert.notNull(singletonFactory, "Singleton factory must not be null");
  synchronized (this.singletonObjects) {
    if (!this.singletonObjects.containsKey(beanName)) {
      // 在singletonFactories中暴露
      this.singletonFactories.put(beanName, singletonFactory);
      this.earlySingletonObjects.remove(beanName);
      // 在registeredSingletons中暴露
      this.registeredSingletons.add(beanName);
     }
   }
}

初始化bean实例
InstantiationAwareBeanPostProcessor#postProcessAfterInstantiation🚩
populateBean 处理IOC注入逻辑autowireByName，autowireByType
InstantiationAwareBeanPostProcessor#postProcessPropertyValues🚩
初始化 initializeBean
invokeAwareMethods 处理BeanNameAware/BeanClassLoaderAware/BeanFactoryAware🚩
BeanPostProcessor#postProcessBeforeInitialization🚩
InitializingBean#afterPropertiesSet🚩
initMethodName执行🚩
BeanPostProcessor#postProcessAfterInitialization🚩

getObjectForBeanInstance

beanName以&开头，实例不是FactoryBean实现类，报错
实例不是FactoryBean实现类或beanName以&开头，返回实例
beanName不以&开头并且实例是FactoryBean实现类
传入beanDefinition为空，尝试从factoryBeanObjectCache缓存中获取
getObjectFromFactoryBean
factory.getObject()
非合成的bean，BeanPostProcessor处理
postProcessObjectFromFactoryBean=》beanProcessor.postProcessAfterInitialization

变量：
Set<String> singletonsCurrentlyInCreation
Map<String, ObjectFactory<?>> singletonFactories
Map<String, Object> earlySingletonObjects
Map<String, Object> factoryBeanObjectCache
Map<String, BeanDefinition> beanDefinitionMap
Map<String, RootBeanDefinition> mergedBeanDefinitions
ThreadLocal<Object> prototypesCurrentlyInCreation
Set<String> alreadyCreated
Map<String, Set<String>> dependentBeanMap
Map<String, Set<String>> dependenciesForBeanMap