BeanFactory系列

DefaultListableBeanFactory

描述

BeanFactory

定义容器接口。核心方法:

//从容器中获取beanObject getBean(String name) throws BeansException;

HierarchicalBeanFactory

扩展容器的层次结构。核心方法:

//获取父容器BeanFactory getParentBeanFactory();

ListableBeanFactory

扩展容器的遍历功能，BeanFatory只能使用名称获取bean，ListableBeanFactory可以遍历容器中的bean。核心方法：

(资料图片)

//返回此类（包括子类）的bean，如果type为空，返回所有bean。 Map getBeansOfType(@Nullable Class type) throws BeansException;//返回此类（包括子类）的bean名称。String[] getBeanNamesForType(@Nullable Class type);

AutowireCapableBeanFactory

扩展自动装配功能，不过此接口一般不在应用中直接使用，也不太常用

SingletonBeanRegistry

该接口定义了共享单例bean实例的注册中心，提供注册单例bean到容器和从容器中获取单例bean的功能，BeanFactory的子类来做实现。方法：

//注册单例Beanvoid registerSingleton(String beanName, Object singletonObject);//获取单例BeanObject getSingleton(String beanName);

DefaultSingletonBeanRegistry

核心类，实现了SingletonBeanRegistry接口。实现注册bean，获取bean。字段：各种map，存放bean

/** Cache of singleton objects: bean name to bean instance. */  private final Map singletonObjects = new ConcurrentHashMap<>(256);    /** Cache of singleton factories: bean name to ObjectFactory. */  private final Map> singletonFactories = new HashMap<>(16);    /** Cache of early singleton objects: bean name to bean instance. */  private final Map earlySingletonObjects = new HashMap<>(16);    /** Set of registered singletons, containing the bean names in registration order. */  private final Set registeredSingletons = new LinkedHashSet<>(256);

FactoryBeanRegistrySupport

抽象类，继承DefaultSingletonBeanRegistry，提供FactoryBean的注册。方法：

//获取FactoryBean创建的Object，不是FactoryBean本身对象//最终调用object = factory.getObject();使用factory创建对象protected Object getObjectFromFactoryBean(FactoryBean factory, String beanName, boolean shouldPostProcess);

字段：存储factoryBean创建的对象，缓存的原因未知，具体使用场景未知

private final Map factoryBeanObjectCache = new ConcurrentHashMap<>(16);

ConfigurableBeanFactory

接口，继承HierarchicalBeanFactory, SingletonBeanRegistry接口。扩展对BeanFactory配置的功能，内部使用，不在应用程序中使用，应用中应该使用BeanFactory和ListableBeanFactory。核心方法：

void setParentBeanFactory(BeanFactory parentBeanFactory) throws IllegalStateException;void addBeanPostProcessor(BeanPostProcessor beanPostProcessor);

ConfigurableListableBeanFactory

接口，继承ListableBeanFactory, AutowireCapableBeanFactory, ConfigurableBeanFactory接口，就当它是一个聚合接口吧，内部使用，使用场景未知。方法：

BeanDefinition getBeanDefinition(String beanName) throws NoSuchBeanDefinitionException;

AbstractAutowireCapableBeanFactory

核心类，抽象类，继承AbstractBeanFactory，实现AutowireCapableBeanFactory。实现了容器的基本功能，主要功能为创建bean。核心方法：

public  T createBean(Class beanClass) throws BeansException;public Object initializeBean(Object existingBean, String beanName);

BeanDefinitionRegistry

接口，bean定义的注册。

void registerBeanDefinition(String beanName, BeanDefinition beanDefinition)  throws BeanDefinitionStoreException;void removeBeanDefinition(String beanName) throws NoSuchBeanDefinitionException;BeanDefinition getBeanDefinition(String beanName) throws NoSuchBeanDefinitionException;

DefaultListableBeanFactory

核心类，继承AbstractAutowireCapableBeanFactory，实现ConfigurableListableBeanFactory, BeanDefinitionRegistry接口，实现一个较完善的BeanFacotry。

public  T getBean(Class requiredType) throws BeansException;

ApplicationContext系列

ClassPathXmlApplicationContext

ResourceLoader

加载资源相关

ApplicationContext

核心接口，继承ListableBeanFactory，拥有访问BeanFactory的功能，继承ResourceLoader，拥有加载资源的能力。方法：

ApplicationContext getParent();// 暴露AutowireCapableBeanFactoryAutowireCapableBeanFactory getAutowireCapableBeanFactory() throws IllegalStateException;

Lifecycle

生命周明接口

void start();void stop();boolean isRunning();

ConfigurableApplicationContext

接口，提供配置ApplicationContext的功能。接口注释中提到此接口是SPI接口，不太懂。方法：

void setParent(@Nullable ApplicationContext parent);void setEnvironment(ConfigurableEnvironment environment);//添加BeanFactoryPostProcessorvoid addBeanFactoryPostProcessor(BeanFactoryPostProcessor postProcessor);//加载或刷新配置，初始化BeanFactoryvoid refresh() throws BeansException, IllegalStateException;

AbstractApplicationContext

ApplicationContext的实现，使用模板模式（主要是refresh方法）。核心方法：

public void refresh() throws BeansException, IllegalStateException {   synchronized (this.startupShutdownMonitor) {     // Prepare this context for refreshing.     prepareRefresh();     // Tell the subclass to refresh the internal bean factory.     ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();     // Prepare the bean factory for use in this context.     prepareBeanFactory(beanFactory);     try {       // Allows post-processing of the bean factory in context subclasses.       postProcessBeanFactory(beanFactory);       // Invoke factory processors registered as beans in the context.       invokeBeanFactoryPostProcessors(beanFactory);       // Register bean processors that intercept bean creation.       registerBeanPostProcessors(beanFactory);       // Initialize message source for this context.       initMessageSource();       // Initialize event multicaster for this context.       initApplicationEventMulticaster();       // Initialize other special beans in specific context subclasses.       onRefresh();       // Check for listener beans and register them.       registerListeners();       // Instantiate all remaining (non-lazy-init) singletons.       finishBeanFactoryInitialization(beanFactory);       // Last step: publish corresponding event.       finishRefresh();     }     catch (BeansException ex) {       if (logger.isWarnEnabled()) {       logger.warn("Exception encountered during context initialization - " +       "cancelling refresh attempt: " + ex);     }     // Destroy already created singletons to avoid dangling resources.     destroyBeans();     // Reset "active" flag.     cancelRefresh(ex);     // Propagate exception to caller.     throw ex;     }     finally {     // Reset common introspection caches in Spring"s core, since we     // might not ever need metadata for singleton beans anymore...     resetCommonCaches();     }   } }

refresh核心步骤

//创建BeanFactory，new一个DefaultListableBeanFactoryConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory(); //执行BeanFactoryPostProcessor，对容器后置处理//BeanFactoryPostProcessor接口只有postProcessBeanFactory，没有前置处理方法invokeBeanFactoryPostProcessors(beanFactory); //注册BeanPostProcessor//从容器中遍历BeanPostProcessor，注册到容器registerBeanPostProcessors(beanFactory);//完成beanFactory初始化，最重要是的实例化单例bean//通过调用beanFactory的preInstantiateSingletons()，此方法有DefaultListableBeanFactory实现，是核心方法finishBeanFactoryInitialization(beanFactory);

AbstractRefreshableApplicationContext

抽象类，AbstractApplicationContext的实现。主要实现刷新（包括第一次刷新，即启动）容器的功能：

1. 刷新BeanFatory，如果已存在，则删除重新创建BeanFactory
2. 加载不同配置（xml，文件，等）到BeanFactory方法：

// 实现了父类AbstractApplicationContext中的刷新容器方法protected final void refreshBeanFactory() throws BeansException;// 加载bean定义到BeanFactoryprotected abstract void loadBeanDefinitions(DefaultListableBeanFactory beanFactory)  throws BeansException, IOException;

Aware

标记接口，无任何方法，只是作为标记，有时候很有用。Aware的作用是标识bean有可以回调来从容器中获取某种信息。

BeanNameAware

从容器中获取beanName

// 并不是设置name，参数的name是容器暴露出来的，用于我们使用void setBeanName(String name);

InitializingBean

接口，由bean来实现，在bean的属性被设置后调用，处理自定义的初始化操作

void afterPropertiesSet() throws Exception;

AbstractRefreshableConfigApplicationContext

抽象类，设置配置文件路径

public void setConfigLocation(String location);

AbstractXmlApplicationContext

抽象类，处理xml类型的配置文件加载解析

ClassPathXmlApplicationContext

提供参数为xml配置文件路径的构造方法

AnnotationConfigApplicationContext

注解AnnotationConfigApplicationContext并不是继承AbstractRefreshableApplicationContext或AbstractRefreshableConfigApplicationContext，而是继承的AbstractApplicationContext，AbstractApplicationContext中有最核心的refresh流程

GenericApplicationContext

通用ApplicationContext实现，它持有单个内部DefaultListableBeanFactory实例。ClassPathXmlApplicationContext并没有继承自此类，但是此类也可以用于读取xml配置文件做ApplicationContext。此类可用于自定义的ApplicationContext。典型的用法是通过BeanDefinitionRegistry接口注册各种bean定义，然后调用refresh()初始化这些bean。使用示例：

GenericApplicationContext ctx = new GenericApplicationContext();XmlBeanDefinitionReader xmlReader = new XmlBeanDefinitionReader(ctx);xmlReader.loadBeanDefinitions(new ClassPathResource("applicationContext.xml"));PropertiesBeanDefinitionReader propReader = new PropertiesBeanDefinitionReader(ctx);propReader.loadBeanDefinitions(new ClassPathResource("otherBeans.properties"));ctx.refresh();MyBean myBean = (MyBean) ctx.getBean("myBean");

方法：

public void registerBeanDefinition(String beanName, BeanDefinition beanDefinition)  throws BeanDefinitionStoreException;

AnnotationConfigRegistry

用于注释配置应用程序上下文的公共接口，定义注册和扫描方法。

//注册带注解的类void register(Class... annotatedClasses);void scan(String... basePackages);

AnnotationConfigApplicationContext

注解配置ApplicationContext方法：

// 使用时就是调用构造方法，构造方法中传入配置类，然后注册配置中的bean，refresh//this()无参构造，会注册一个ConfigurationClassPostProcessor，来处理@Configuration,@Bean,@Import等注解，把注入的bean注册到容器中public AnnotationConfigApplicationContext(Class... annotatedClasses) {  this();  register(annotatedClasses);  refresh();  }