39 lines
1.4 KiB
Markdown
39 lines
1.4 KiB
Markdown
## 顺序获取单例
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1. private final Map<String, Object> singletonObjects = new ConcurrentHashMap<>(256);
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2. private final Map<String, Object> earlySingletonObjects = new ConcurrentHashMap<>(16);
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3. private final Map<String, ObjectFactory<?>> singletonFactories = new HashMap<>(16);
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## 循环依赖
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```java
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// 单例顺序获取失败
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// Fail if we're already creating this bean instance:
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// We're assumably within a circular reference.
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```
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1. 判断是否存在父类中，如果存在从父类中获取。
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2. 设置正在创建
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3. RootBeanDefinition mbd = getMergedLocalBeanDefinition(beanName);
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4. 判断单例、原型或者其他
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5. 创建bean，检验检测状态
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1. Make sure bean class is actually resolved at this point, and clone the bean definition in case of a dynamically resolved Class which cannot be stored in the shared merged bean definition.
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2. doCreateBean
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1. createBeanInstance
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2. Eagerly cache singletons to be able to resolve circular references even when triggered by lifecycle interfaces like BeanFactoryAware.放入三级缓存中addSingletonFactory(beanName, () -> getEarlyBeanReference(beanName, mbd, bean))
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3. Give any InstantiationAwareBeanPostProcessors the opportunity to modify the state of the bean before properties are set. This can be used, for example,to support styles of field injection.
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## 重要类
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```java
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BeanDefinition、ClassLoader
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```
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