Spring源码笔记之SpringIOC--（2）从BeanDefinition到Bean实例

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从BeanDefinition到Bean实例

对比SimpleBeanDefinitionRegistry和DefaultListableBeanFactory的源码，中间省略一些无关紧要的逻辑：

SimpleBeanDefinitionRegistry.java

public class SimpleBeanDefinitionRegistry extends SimpleAliasRegistry implements BeanDefinitionRegistry {/** Map of bean definition objects, keyed by bean name. */private final Map<String, BeanDefinition> beanDefinitionMap = new ConcurrentHashMap<>(64);@Overridepublic void registerBeanDefinition(String beanName, BeanDefinition beanDefinition)throws BeanDefinitionStoreException {this.beanDefinitionMap.put(beanName, beanDefinition);}@Overridepublic BeanDefinition getBeanDefinition(String beanName) throws NoSuchBeanDefinitionException {BeanDefinition bd = this.beanDefinitionMap.get(beanName);if (bd == null) {throw new NoSuchBeanDefinitionException(beanName);}return bd;}
}

DefaultListableBeanFactory.java

public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFactoryimplements ConfigurableListableBeanFactory, BeanDefinitionRegistry, Serializable {/** Map of bean definition objects, keyed by bean name. */private final Map<String, BeanDefinition> beanDefinitionMap = new ConcurrentHashMap<>(256);@Overridepublic void registerBeanDefinition(String beanName, BeanDefinition beanDefinition)throws BeanDefinitionStoreException {// 实现比较复杂暂时省略}@Overridepublic BeanDefinition getBeanDefinition(String beanName) throws NoSuchBeanDefinitionException {// 实现比较复杂暂时省略}@Overridepublic Object getBean(String name) throws BeansException {assertBeanFactoryActive();return getBeanFactory().getBean(name);}@Overridepublic <T> T getBean(Class<T> requiredType) throws BeansException {return getBean(requiredType, (Object[]) null);}
}