Spring IOC源码解析（10）AbstractBeanFactory

前言

AbstractBeanFactory是bean工厂最核心的实现。我们首先分析其字段，再分析其方法。

字段信息

// 父类bean工厂
/** Parent bean factory, for bean inheritance support. */
@Nullable
private BeanFactory parentBeanFactory;

// bean类加载器
/** ClassLoader to resolve bean class names with, if necessary. */
@Nullable
private ClassLoader beanClassLoader = ClassUtils.getDefaultClassLoader();

// bean临时类加载器
/** ClassLoader to temporarily resolve bean class names with, if necessary. */
@Nullable
private ClassLoader tempClassLoader;

// 是否缓存bean元数据
/** Whether to cache bean metadata or rather reobtain it for every access. */
private boolean cacheBeanMetadata = true;

// bean表达式解析器
/** Resolution strategy for expressions in bean definition values. */
@Nullable
private BeanExpressionResolver beanExpressionResolver;

// 转换服务
/** Spring ConversionService to use instead of PropertyEditors. */
@Nullable
private ConversionService conversionService;

// 自定义属性编辑器注册器
/** Custom PropertyEditorRegistrars to apply to the beans of this factory. */
private final Set propertyEditorRegistrars = new LinkedHashSet<>(4);

// 自定义属性编辑器
/** Custom PropertyEditors to apply to the beans of this factory. */
private final Map, Class> customEditors = new HashMap<>(4);

// 自定义类型转换器
/** A custom TypeConverter to use, overriding the default PropertyEditor mechanism. */
@Nullable
private TypeConverter typeConverter;

// 为嵌入的值（如注解属性）添加字符串解析器
/** String resolvers to apply e.g. to annotation attribute values. */
private final List embeddedValueResolvers = new CopyOnWriteArrayList<>();

// bean后置处理器
/** BeanPostProcessors to apply in createBean. */
private final List beanPostProcessors = new CopyOnWriteArrayList<>();

// InstantiationAwareBeanPostProcessors是否已注册
/** Indicates whether any InstantiationAwareBeanPostProcessors have been registered. */
private volatile boolean hasInstantiationAwareBeanPostProcessors;

// DestructionAwareBeanPostProcessors是否已注册
/** Indicates whether any DestructionAwareBeanPostProcessors have been registered. */
private volatile boolean hasDestructionAwareBeanPostProcessors;

// bean作用域
/** Map from scope identifier String to corresponding Scope. */
private final Map scopes = new LinkedHashMap<>(8);

// 安全作用上下文提供者
/** Security context used when running with a SecurityManager. */
@Nullable
private SecurityContextProvider securityContextProvider;

// 合并后的根BeanDefinition
/** Map from bean name to merged RootBeanDefinition. */
private final Map mergedBeanDefinitions = new ConcurrentHashMap<>(256);

// bean是否已创建
/** Names of beans that have already been created at least once. */
private final Set alreadyCreated = Collections.newSetFromMap(new ConcurrentHashMap<>(256));

// 正在创建的prototype类型的bean，之所以使用ThreadLocal，是为了避免多线程创建的冲突
/** Names of beans that are currently in creation. */
private final ThreadLocal