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1751 2017-12-02 2024-07-28

DefaultListableBeanFactory类被称为Spring的发动机/导火索，这次我们先从类层次结构上来了解下。

重点看下接口层面方法，具体的实现类先不细究（为了简化阅读，只保留了基础的方法，去掉大部分注释）。

一、类结构

DefaultListableBeanFactory是Spring中最为核心的几个类之一。它的类声明如下

/**
 * Default implementation of the
 * {@link org.springframework.beans.factory.ListableBeanFactory} and
 * {@link BeanDefinitionRegistry} interfaces: a full-fledged bean factory
 * based on bean definition objects.
 *
 * <p>Typical usage is registering all bean definitions first (possibly read
 * from a bean definition file), before accessing beans. Bean definition lookup
 * is therefore an inexpensive operation in a local bean definition table,
 * operating on pre-built bean definition metadata objects.
 *
 * <p>Can be used as a standalone bean factory, or as a superclass for custom
 * bean factories. Note that readers for specific bean definition formats are
 * typically implemented separately rather than as bean factory subclasses:
 * see for example {@link PropertiesBeanDefinitionReader} and
 * {@link org.springframework.beans.factory.xml.XmlBeanDefinitionReader}.
 *
 * <p>For an alternative implementation of the
 * {@link org.springframework.beans.factory.ListableBeanFactory} interface,
 * have a look at {@link StaticListableBeanFactory}, which manages existing
 * bean instances rather than creating new ones based on bean definitions.
 *
 */
// 这里简单翻译下还是很有必要的，大致意思如下：DefaultListableBeanFactory是一个成熟的基于BeanDefinition对象的BeanFactory。在内存中操作BeanDefinition元数据是很容易的，难的是从外部文件读取BeanDefinition。需要注意，从外部读取BeanDefinitions的工作是委托个外部做的，子类也不需要管。该类只提供一个注册BeanDefinition的方法：registerBeanDefinition(String beanName, BeanDefinition beanDefinition)
public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFactory
        implements ConfigurableListableBeanFactory, BeanDefinitionRegistry, Serializable {
    // 省略其他代码
}

DefaultListableBeanFactory是整个bean加载的核心部分，是Spring注册及加载bean的默认实现。

DefaultListableBeanFactory 继承了 AbstractAutowireCapableBeanFactory，并实现了 ConfigurableListableBeanFactory以及 BeanDefinitionRegistry接口。以下是DefaultListableBeanFactory的类图。

DefaultListableBeanFactory类图

从上面的类图中，我们可以很清晰地从全局角度了解DefaultListableBeanFactory的脉络。先简单地了解一下上面类图中的各个类的作用，如下（自上而下，自左向右）

  • AliasRegistry（接口）：定义对alias（别名）的简单增删改等操作。
  • BeanDefinitionRegistry（接口）：定义对BeanDefinition的各种增删改操作。
  • SimpleAliasRegistry：主要使用map作为alias的缓存，并对接口AliasRegistry进行实现。
  • SingletonBeanRegistry（接口）：定义对单例的注册及获取。
  • BeanFactory(接口)：定义获取bean及bean的各种属性。
  • DefaultSingletonBeanRegistry：对接口SingletonBeanRegistry各函数的实现。
  • HierarchicaBeanFactory（接口）：继承BeanFactory，也就是在BeanFactory定义的功能的基础上增加对parentFactory的支持。
  • ListableBeanFactory（接口）：根据各种条件获取bean的配置清单。
  • FactoryBeanRegistrySupport：在DefaultListableBeanFactory的基础上，增加对FactoryBean的特殊处理功能。
  • ConfigurableBeanFactory（接口）：提供配置Factory的各种方法。
  • AbstractBeanFactory：综合FactoryBeanRegistrySupport和ConfigurableBeanFactory的功能。
  • AutowireCapableBeanFactory（接口）：提供创建Bean、自动注入、初始化以及应用bean的后处理器。
  • AbstractAutowireCapableBeanFactory：综合AbstractBeanFactory并对接口AutowireCapableBeanFactory进行实现。
  • ConfigurableListableBeanFactory（接口）：BeanFactory配置清单，指定忽略类型及接口等。
  • DefaultListableBeanFactory：综合上面所有功能，主要是对Bean注册后的处理。

下面我们针对最上层的几个接口进行说明，请自行阅读相关注释（第一次看不懂很正常，后面回过头来多看看就好了）。

二、上层接口

接口是对事物特性的封装展现，因此我们先看下DefaultListableBeanFactory所实现的接口的具体定义。

1、AliasRegistry

别名的注册管理器接口，代码如下

public interface AliasRegistry {

    void registerAlias(String name, String alias);

    void removeAlias(String alias);

    boolean isAlias(String beanName);

    String[] getAliases(String name);
}

2、BeanDefinitionRegistry

BeanDefinition的注册管理器接口，代码如下

public interface BeanDefinitionRegistry extends AliasRegistry {

    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);
}

3、BeanFactory

管理bean的最顶层工厂接口，代码如下

public interface BeanFactory {

    String FACTORY_BEAN_PREFIX = "&";

    Object getBean(String name) throws BeansException;

    <T> T getBean(String name, Class<T> requiredType) throws BeansException;

    <T> T getBean(Class<T> requiredType) throws BeansException;

    Object getBean(String name, Object... args) throws BeansException;

    boolean containsBean(String name);

    boolean isSingleton(String name) throws NoSuchBeanDefinitionException;

    boolean isPrototype(String name) throws NoSuchBeanDefinitionException;

    boolean isTypeMatch(String name, Class<?> targetType) throws NoSuchBeanDefinitionException;

    Class<?> getType(String name) throws NoSuchBeanDefinitionException;

    String[] getAliases(String name);
}

4、SingletonBeanRegistry

单例bean的注册管理器接口，代码如下

public interface SingletonBeanRegistry {

    void registerSingleton(String beanName, Object singletonObject);

    Object getSingleton(String beanName);

    boolean containsSingleton(String beanName);

    String[] getSingletonNames();

    int getSingletonCount();
}

5、HierarchicalBeanFactory

分层的bean工厂接口，代码如下

public interface HierarchicalBeanFactory extends BeanFactory {

    BeanFactory getParentBeanFactory();

    boolean containsLocalBean(String name);
}

6、ListableBeanFactory

可列举的bean工厂接口，定义了大量获取bean的方法，代码如下

public interface ListableBeanFactory extends BeanFactory {

    boolean containsBeanDefinition(String beanName);

    int getBeanDefinitionCount();

    String[] getBeanDefinitionNames();

    String[] getBeanNamesForType(Class<?> type);

    String[] getBeanNamesForType(Class<?> type, boolean includeNonSingletons, boolean allowEagerInit);

    <T> Map<String, T> getBeansOfType(Class<T> type) throws BeansException;

    <T> Map<String, T> getBeansOfType(Class<T> type, boolean includeNonSingletons, boolean allowEagerInit)
            throws BeansException;

    Map<String, Object> getBeansWithAnnotation(Class<? extends Annotation> annotationType)
            throws BeansException;

    <A extends Annotation> A findAnnotationOnBean(String beanName, Class<A> annotationType);
}

7、ConfigurableBeanFactory

配置bean工厂的接口，提供配置bean工厂的各种方法，代码如下

public interface ConfigurableBeanFactory extends HierarchicalBeanFactory, SingletonBeanRegistry {

    String SCOPE_SINGLETON = "singleton";

    String SCOPE_PROTOTYPE = "prototype";

    void setParentBeanFactory(BeanFactory parentBeanFactory) throws IllegalStateException;

    void setBeanClassLoader(ClassLoader beanClassLoader);

    ClassLoader getBeanClassLoader();

    void setTempClassLoader(ClassLoader tempClassLoader);

    ClassLoader getTempClassLoader();

    void setCacheBeanMetadata(boolean cacheBeanMetadata);

    boolean isCacheBeanMetadata();

    void setBeanExpressionResolver(BeanExpressionResolver resolver);

    BeanExpressionResolver getBeanExpressionResolver();

    void setConversionService(ConversionService conversionService);

    ConversionService getConversionService();

    void addPropertyEditorRegistrar(PropertyEditorRegistrar registrar);

    void registerCustomEditor(Class<?> requiredType, Class<? extends PropertyEditor> propertyEditorClass);

    void copyRegisteredEditorsTo(PropertyEditorRegistry registry);

    void setTypeConverter(TypeConverter typeConverter);

    TypeConverter getTypeConverter();

    void addEmbeddedValueResolver(StringValueResolver valueResolver);

    String resolveEmbeddedValue(String value);

    void addBeanPostProcessor(BeanPostProcessor beanPostProcessor);

    int getBeanPostProcessorCount();

    void registerScope(String scopeName, Scope scope);

    String[] getRegisteredScopeNames();

    Scope getRegisteredScope(String scopeName);

    AccessControlContext getAccessControlContext();

    void copyConfigurationFrom(ConfigurableBeanFactory otherFactory);

    void registerAlias(String beanName, String alias) throws BeanDefinitionStoreException;

    void resolveAliases(StringValueResolver valueResolver);

    BeanDefinition getMergedBeanDefinition(String beanName) throws NoSuchBeanDefinitionException;

    boolean isFactoryBean(String name) throws NoSuchBeanDefinitionException;

    void setCurrentlyInCreation(String beanName, boolean inCreation);

    boolean isCurrentlyInCreation(String beanName);

    void registerDependentBean(String beanName, String dependentBeanName);

    String[] getDependentBeans(String beanName);

    String[] getDependenciesForBean(String beanName);

    void destroyBean(String beanName, Object beanInstance);

    void destroyScopedBean(String beanName);

    void destroySingletons();
}

8、AutowireCapableBeanFactory

自动装填的bean工厂接口，提供创建bean、自动注入、初始化以及应用bean的后处理器，代码如下

public interface AutowireCapableBeanFactory extends BeanFactory {

    int AUTOWIRE_NO = 0;

    int AUTOWIRE_BY_NAME = 1;

    int AUTOWIRE_BY_TYPE = 2;

    int AUTOWIRE_CONSTRUCTOR = 3;

    @Deprecated
    int AUTOWIRE_AUTODETECT = 4;

    <T> T createBean(Class<T> beanClass) throws BeansException;

    void autowireBean(Object existingBean) throws BeansException;

    Object configureBean(Object existingBean, String beanName) throws BeansException;

    Object resolveDependency(DependencyDescriptor descriptor, 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;

    Object resolveDependency(DependencyDescriptor descriptor, String beanName,
            Set<String> autowiredBeanNames, TypeConverter typeConverter) throws BeansException;
}

9、ConfigurableListableBeanFactory

可列举的配置bean工厂接口，配置BeanFactory，指定忽略类型及接口等，代码如下

public interface ConfigurableListableBeanFactory
        extends ListableBeanFactory, AutowireCapableBeanFactory, ConfigurableBeanFactory {

    void ignoreDependencyType(Class<?> type);

    void ignoreDependencyInterface(Class<?> ifc);

    void registerResolvableDependency(Class<?> dependencyType, Object autowiredValue);

    boolean isAutowireCandidate(String beanName, DependencyDescriptor descriptor)
            throws NoSuchBeanDefinitionException;

    BeanDefinition getBeanDefinition(String beanName) throws NoSuchBeanDefinitionException;

    void freezeConfiguration();

    boolean isConfigurationFrozen();

    void preInstantiateSingletons() throws BeansException;
}

三、上层父类

父类的话，只做简单的类说明，不做过多深究。

1、SimpleAliasRegistry

简单别名注册管理器，代码如下

public class SimpleAliasRegistry implements AliasRegistry {
    //省略代码
}

2、DefaultSingletonBeanRegistry

单例bean的默认注册管理器，代码如下

public class DefaultSingletonBeanRegistry extends SimpleAliasRegistry implements SingletonBeanRegistry {
    //省略代码
}

3、FactoryBeanRegistrySupport

在DefaultSingletonBeanRegistry的基础上增加了对FactoryBean的特殊处理功能，代码如下

public abstract class FactoryBeanRegistrySupport extends DefaultSingletonBeanRegistry {
    //省略代码
}

4、AbstractBeanFactory

综合FactoryBeanRegistry和ConfigurableBeanFactory的功能，代码如下

public abstract class AbstractBeanFactory extends FactoryBeanRegistrySupport implements ConfigurableBeanFactory {
    //省略代码
}

5、AbstractAutowireCapableBeanFactory

综合AbstractBeanFactory并对接口AutowireCapableBeanFactory进行实现，代码如下

public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFactory
        implements AutowireCapableBeanFactory {
    //省略代码
}

纸上得来终觉浅，绝知此事需躬行。一步一个脚印，终究能到达本来难以登顶的高山！

总访问次数: 22次, 一般般帅 创建于 2017-12-02, 最后更新于 2024-07-28

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