spring-BeanFactory的各项实现

本文主要是介绍spring-BeanFactory的各项实现，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

咱们直接看一下AbstractBeanFactory的继承和实现结构:
大体描述一下:AbstractBeanFactory功能结构主要有两部分,1.实现了BeanFactory相关的功能,2.实现了别名,单列注册以及工厂支持.
BeanFactory相关接口前面已经描述过,这里不再重复,接下来看一下2)部分:
1.AliasRegistry别名注册

	//给指定的bean注册别名void registerAlias(String name, String alias);//移除别名void removeAlias(String alias);//别名判断boolean isAlias(String name);//获取所有的别名String[] getAliases(String name);

2.SimpleAliasRegistry别名注册的简单实现类,核心结构如下:

	//别名map,键是别名,值是nameprivate final Map<String, String> aliasMap = new ConcurrentHashMap<>(16);

3.SingletonBeanRegistry单例bean注册支持

	void registerSingleton(String beanName, Object singletonObject);Object getSingleton(String beanName);boolean containsSingleton(String beanName);String[] getSingletonNames();int getSingletonCount();//注册单例的锁,同步对单例结构的更改Object getSingletonMutex();

4.DefaultSingletonBeanRegistry对单列注册的结构性实现
看一下核心结构:

/** Cache of singleton objects: bean name to bean instance. */所有的单列都存储在这个map中private final Map<String, Object> singletonObjects = new ConcurrentHashMap<>(256);/** Cache of singleton factories: bean name to ObjectFactory. */单列对象的创建工厂private final Map<String, ObjectFactory<?>> singletonFactories = new HashMap<>(16);/** Cache of early singleton objects: bean name to bean instance. */正在创建中的beanprivate final Map<String, Object> earlySingletonObjects = new HashMap<>(16);/** Set of registered singletons, containing the bean names in registration order. */按注册顺序的所有注册beanname的集合private final Set<String> registeredSingletons = new LinkedHashSet<>(256);/** Names of beans that are currently in creation. */当前正在创建中的beanprivate final Set<String> singletonsCurrentlyInCreation =Collections.newSetFromMap(new ConcurrentHashMap<>(16));/** Names of beans currently excluded from in creation checks. */排除在创建检查之外的beannameprivate final Set<String> inCreationCheckExclusions =Collections.newSetFromMap(new ConcurrentHashMap<>(16));/** List of suppressed Exceptions, available for associating related causes. */@Nullableprivate Set<Exception> suppressedExceptions;/** Flag that indicates whether we're currently within destroySingletons. */private boolean singletonsCurrentlyInDestruction = false;/** Disposable bean instances: bean name to disposable instance. */需要执行destroy接口的bean的mapprivate final Map<String, Object> disposableBeans = new LinkedHashMap<>();/** Map between containing bean names: bean name to Set of bean names that the bean contains. */描述了bean和内部bean之间关系private final Map<String, Set<String>> containedBeanMap = new ConcurrentHashMap<>(16);/** Map between dependent bean names: bean name to Set of dependent bean names. */描述了当前bean被那些bean依赖的关系private final Map<String, Set<String>> dependentBeanMap = new ConcurrentHashMap<>(64);/** Map between depending bean names: bean name to Set of bean names for the bean's dependencies. */描述了bean和依赖bean之间的关系private final Map<String, Set<String>> dependenciesForBeanMap = new ConcurrentHashMap<>(64);

5.FactoryBeanRegistrySupport工厂支持bean
看一下核心结构:

/** Cache of singleton objects created by FactoryBeans: FactoryBean name to object. */
private final Map<String, Object> factoryBeanObjectCache = new ConcurrentHashMap<>(16);

6.AbstractBeanFactory第一个带有BeanFactory结尾的抽象类,基本成型,先来了解一下他的核心结构:

/** Parent bean factory, for bean inheritance support. */垂直工程结构的支持@Nullableprivate BeanFactory parentBeanFactory;/** ClassLoader to resolve bean class names with, if necessary. */类加载器@Nullableprivate ClassLoader beanClassLoader = ClassUtils.getDefaultClassLoader();/** ClassLoader to temporarily resolve bean class names with, if necessary. */一般在lwt中使用@Nullableprivate ClassLoader tempClassLoader;/** Whether to cache bean metadata or rather reobtain it for every access. */是否缓存bean的元数据,不缓存的话每次创建bean都会重新加载bean的定义private boolean cacheBeanMetadata = true;/** Resolution strategy for expressions in bean definition values. */表达式解析spel@Nullableprivate BeanExpressionResolver beanExpressionResolver;/** Spring ConversionService to use instead of PropertyEditors. */类型安全转换服务@Nullableprivate ConversionService conversionService;/** Custom PropertyEditorRegistrars to apply to the beans of this factory. */属性注册private final Set<PropertyEditorRegistrar> propertyEditorRegistrars = new LinkedHashSet<>(4);/** Custom PropertyEditors to apply to the beans of this factory. */定制的属性编辑器private final Map<Class<?>, Class<? extends PropertyEditor>> customEditors = new HashMap<>(4);/** A custom TypeConverter to use, overriding the default PropertyEditor mechanism. */类型转换@Nullableprivate TypeConverter typeConverter;/** String resolvers to apply e.g. to annotation attribute values. */值解析private final List<StringValueResolver> embeddedValueResolvers = new CopyOnWriteArrayList<>();/** BeanPostProcessors to apply in createBean. */各种BeanPostProcessor集合private final List<BeanPostProcessor> beanPostProcessors = new CopyOnWriteArrayList<>();/** Indicates whether any InstantiationAwareBeanPostProcessors have been registered. */是否有实例化BeanPost后置处理器private volatile boolean hasInstantiationAwareBeanPostProcessors;/** Indicates whether any DestructionAwareBeanPostProcessors have been registered. */是否有DestructionAwareBeanPostProcessors 后置处理器private volatile boolean hasDestructionAwareBeanPostProcessors;/** Map from scope identifier String to corresponding Scope. */各种scopeprivate final Map<String, Scope> scopes = new LinkedHashMap<>(8);/** Security context used when running with a SecurityManager. */@Nullableprivate SecurityContextProvider securityContextProvider;/** Map from bean name to merged RootBeanDefinition. */合并后的bean定义mapprivate final Map<String, RootBeanDefinition> mergedBeanDefinitions = new ConcurrentHashMap<>(256);/** Names of beans that have already been created at least once. */已经创建的bean的合集private final Set<String> alreadyCreated = Collections.newSetFromMap(new ConcurrentHashMap<>(256));/** Names of beans that are currently in creation. */正在创建的原型private final ThreadLocal<Object> prototypesCurrentlyInCreation =new NamedThreadLocal<>("Prototype beans currently in creation");

7.AutowireCapableBeanFactory可注入bean工厂

	<T> T createBean(Class<T> beanClass) throws BeansException;void autowireBean(Object existingBean) throws BeansException;Object configureBean(Object existingBean, String beanName) throws BeansException;Object createBean(Class<?> beanClass, int autowireMode, boolean dependencyCheck) throws BeansException;Object autowire(Class<?> beanClass, int autowireMode, boolean dependencyCheck) throws BeansException;void autowireBeanProperties(Object existingBean, int autowireMode, boolean dependencyCheck)throws BeansException;void applyBeanPropertyValues(Object existingBean, String beanName) throws BeansException;Object initializeBean(Object existingBean, String beanName) throws BeansException;Object applyBeanPostProcessorsBeforeInitialization(Object existingBean, String beanName)throws BeansException;Object applyBeanPostProcessorsAfterInitialization(Object existingBean, String beanName)throws BeansException;void destroyBean(Object existingBean);<T> NamedBeanHolder<T> resolveNamedBean(Class<T> requiredType) throws BeansException;Object resolveDependency(DependencyDescriptor descriptor, @Nullable String requestingBeanName) throws BeansException;Object resolveDependency(DependencyDescriptor descriptor, @Nullable String requestingBeanName,@Nullable Set<String> autowiredBeanNames, @Nullable TypeConverter typeConverter) throws BeansException;}

讲一个bean工厂转换成,该结构后可以单独使用手动创建bean,自动注入字段等功能.

8.DefaultListableBeanFactory默认可枚举工厂,默认的ApplicationContext创建的就是这个对象,通过他可以
简单的描述一下他的结构:

/** Map from serialized id to factory instance. */private static final Map<String, Reference<DefaultListableBeanFactory>> serializableFactories =new ConcurrentHashMap<>(8);/** Optional id for this factory, for serialization purposes. */@Nullableprivate String serializationId;/** Whether to allow re-registration of a different definition with the same name. */private boolean allowBeanDefinitionOverriding = true;/** Whether to allow eager class loading even for lazy-init beans. */private boolean allowEagerClassLoading = true;/** Optional OrderComparator for dependency Lists and arrays. */@Nullableprivate Comparator<Object> dependencyComparator;/** Resolver to use for checking if a bean definition is an autowire candidate. */private AutowireCandidateResolver autowireCandidateResolver = new SimpleAutowireCandidateResolver();/** Map from dependency type to corresponding autowired value. */可解析的依赖private final Map<Class<?>, Object> resolvableDependencies = new ConcurrentHashMap<>(16);/** Map of bean definition objects, keyed by bean name. */bean定义表private final Map<String, BeanDefinition> beanDefinitionMap = new ConcurrentHashMap<>(256);/** Map of singleton and non-singleton bean names, keyed by dependency type. */private final Map<Class<?>, String[]> allBeanNamesByType = new ConcurrentHashMap<>(64);/** Map of singleton-only bean names, keyed by dependency type. */private final Map<Class<?>, String[]> singletonBeanNamesByType = new ConcurrentHashMap<>(64);/** List of bean definition names, in registration order. */private volatile List<String> beanDefinitionNames = new ArrayList<>(256);/** List of names of manually registered singletons, in registration order. */private volatile Set<String> manualSingletonNames = new LinkedHashSet<>(16);/** Cached array of bean definition names in case of frozen configuration. */@Nullableprivate volatile String[] frozenBeanDefinitionNames;/** Whether bean definition metadata may be cached for all beans. */private volatile boolean configurationFrozen = false;

9.BeanDefinitionRegistry接口,所有的bean的定义都是通过这里的api注入到beanfactory中,常见的有解析xml配置或注解配置,然后注入到bean工厂中,看一下他的接口视图:

void registerBeanDefinition(String beanName, BeanDefinition beanDefinition)throws BeanDefinitionStoreException;void removeBeanDefinition(String beanName) throws NoSuchBeanDefinitionException;BeanDefinition getBeanDefinition(String beanName) throws NoSuchBeanDefinitionException;boolean containsBeanDefinition(String beanName);String[] getBeanDefinitionNames();int getBeanDefinitionCount();boolean isBeanNameInUse(String beanName);

下一节,我们一起看一下ApplicationContext的结构,然后进行一些必要的实践,加深对运行过程中,各个结构如何协调工作,具体存储数据的视图.

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