手把手教你看 Spring 源码

public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFactory
    implements ConfigurableListableBeanFactory, BeanDefinitionRegistry, Serializable {
@Nullable
  private static Class<?> javaxInjectProviderClass;

  static {
    try {
      javaxInjectProviderClass =
          ClassUtils.forName("javax.inject.Provider", DefaultListableBeanFactory.class.getClassLoader());
    }
    catch (ClassNotFoundException ex) {
      // JSR-330 API not available - Provider interface simply not supported then.
      javaxInjectProviderClass = null;
    }
  }


  /** 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. */
  @Nullable
  private 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. */
  @Nullable
  private Comparator<Object> dependencyComparator;

  /** Resolver to use for checking if a bean definition is an autowire candidate. */
  private AutowireCandidateResolver autowireCandidateResolver = SimpleAutowireCandidateResolver.INSTANCE;

  /** Map from dependency type to corresponding autowired value. */
  private final Map<Class<?>, Object> resolvableDependencies = new ConcurrentHashMap<>(16);

  /** Map of bean definition objects, keyed by bean name. */
  private final Map<String, BeanDefinition> beanDefinitionMap = new ConcurrentHashMap<>(256);

  /** Map from bean name to merged BeanDefinitionHolder. */
  private final Map<String, BeanDefinitionHolder> mergedBeanDefinitionHolders = 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. */
  @Nullable
  private volatile String[] frozenBeanDefinitionNames;
................
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}

import org.springframework.aop.Advisor;
import org.springframework.aop.Pointcut;
import org.springframework.aop.TargetSource;
import org.springframework.aop.framework.AopInfrastructureBean;
import org.springframework.aop.framework.ProxyFactory;
import org.springframework.aop.framework.ProxyProcessorSupport;
import org.springframework.aop.framework.adapter.AdvisorAdapterRegistry;
import org.springframework.aop.framework.adapter.GlobalAdvisorAdapterRegistry;
import org.springframework.aop.target.SingletonTargetSource;

public abstract class AbstractAutoProxyCreator extends ProxyProcessorSupport 
    implements SmartInstantiationAwareBeanPostProcessor, BeanFactoryAware {
    /**
   *设置公共拦截器。这些必须是当前工厂中的bean名称
   */
  public void setInterceptorNames(String... interceptorNames) {
    this.interceptorNames = interceptorNames;
  }
/**
  为给定的bean创建一个AOP代理
   */
  protected Object createProxy(Class<?> beanClass, @Nullable String beanName,
      @Nullable Object[] specificInterceptors, TargetSource targetSource) {

    if (this.beanFactory instanceof ConfigurableListableBeanFactory) {
      AutoProxyUtils.exposeTargetClass((ConfigurableListableBeanFactory) this.beanFactory, beanName, beanClass);
    }
    ProxyFactory proxyFactory = new ProxyFactory();
    proxyFactory.copyFrom(this);
        
    if (!proxyFactory.isProxyTargetClass()) {
      if (shouldProxyTargetClass(beanClass, beanName)) {
        proxyFactory.setProxyTargetClass(true);
      }
      else {
        evaluateProxyInterfaces(beanClass, proxyFactory);
      }
    }
    Advisor[] advisors = buildAdvisors(beanName, specificInterceptors);
    proxyFactory.addAdvisors(advisors);
    proxyFactory.setTargetSource(targetSource);
    customizeProxyFactory(proxyFactory);
    proxyFactory.setFrozen(this.freezeProxy);
        
    if (advisorsPreFiltered()) {
      proxyFactory.setPreFiltered(true);
    }
    return proxyFactory.getProxy(getProxyClassLoader());
  }
    
    
}

/**
 工厂挂钩，允许自定义修改新bean实例-例如，检查标记接口或使用代理包装bean。<p>通常，通过标记接口*或类似对象填充bean的后处理器将实现{@link #postProcessBeforeInitialization}，而使用代理包装bean的后处理器通常将实现{@link #postProcessAfterInitialization}。<h3>注册</h3> <p> {@ code ApplicationContext}可以在其bean定义中自动检测{@code BeanPostProcessor} bean，并将这些后处理器应用于随后创建的任何bean。普通的{@code BeanFactory}允许以编程方式注册后处理器，并将其应用于通过bean工厂创建的所有bean
 */
public interface BeanPostProcessor {

  /**
   在任何bean 初始化回调（如InitializingBean的{@code afterPropertiesSet} 或自定义的init-method）之前，将此{@code BeanPostProcessor}应用于给定的新bean实例<i> </ i>。该bean将已经用属性值填充。返回的bean实例也可能是原始实例的包装;
   */
  @Nullable
  default Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
    return bean;
  }

  /**
在任何bean 初始化回调（例如InitializingBean的{@code afterPropertiesSet} 或自定义的初始化方法）之后，将此{@code BeanPostProcessor}应用于给定的新bean实例。该bean将已经用属性值填充。返回的bean实例可能是原始实例的包装。对于FactoryBean，将为FactoryBean 实例和由FactoryBean创建的对象（从Spring 2.0开始）调用此回调。后处理器可以通过相应的{@code bean instanceof FactoryBean}检查来决定是应用到FactoryBean还是创建的对象，还是两者都应用。
   */
  @Nullable
  default Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
    return bean;
  }

}

public interface BeanFactoryPostProcessor {
  /**
  在标准初始化之后，修改应用程序上下文的内部bean工厂。所有bean定义都将被加载，但是还没有实例化bean *。这甚至可以覆盖或添加*属性，甚至可以用于初始化bean。
   */
  void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException;}

public abstract class AbstractFactoryBean<T>
    implements FactoryBean<T>, BeanClassLoaderAware, BeanFactoryAware, InitializingBean, DisposableBean {
  /** Logger available to subclasses. */
  protected final Log logger = LogFactory.getLog(getClass());
  private boolean singleton = true;
  @Nullable
  private ClassLoader beanClassLoader = ClassUtils.getDefaultClassLoader();
  @Nullable
  private BeanFactory beanFactory;
  private boolean initialized = false;
  @Nullable
  private T singletonInstance;
  @Nullable
  private T earlySingletonInstance;

  /**
      设置是否应该创建一个单例，或者在每个请求上创建一个新对象*否则。默认值为{@code true}（单例）。
   */
  public void setSingleton(boolean singleton) {
    this.singleton = singleton;
  }
  @Override
  public boolean isSingleton() {
    return this.singleton;
  }
  @Override
  public void setBeanClassLoader(ClassLoader classLoader) {
    this.beanClassLoader = classLoader;
  }
  @Override
  public void setBeanFactory(@Nullable BeanFactory beanFactory) {
    this.beanFactory = beanFactory;
  }
  /**
   返回运行该bean的BeanFactory
   */
  @Nullable
  protected BeanFactory getBeanFactory() {
    return this.beanFactory;
  }

  /**
      从运行该bean的BeanFactory获取一个bean类型转换器
   */
  protected TypeConverter getBeanTypeConverter() {
    BeanFactory beanFactory = getBeanFactory();
    if (beanFactory instanceof ConfigurableBeanFactory) {
      return ((ConfigurableBeanFactory) beanFactory).getTypeConverter();
    }
    else {
      return new SimpleTypeConverter();
    }
  }
    /**
       公开单例实例（用于通过“早期单例”代理访问）。返回此FactoryBean持有的单例实例
   */
  @Nullable
  private T getSingletonInstance() throws IllegalStateException {
    Assert.state(this.initialized, "Singleton instance not initialized yet");
    return this.singletonInstance;
  }
}

public interface ApplicationContext extends EnvironmentCapable, ListableBeanFactory, HierarchicalBeanFactory,
    MessageSource, ApplicationEventPublisher, ResourcePatternResolver {

  /**
      返回此应用程序上下文的唯一ID
   */
  @Nullable
  String getId();

  /**
  返回此上下文所属的已部署应用程序的名称
   */
  String getApplicationName();

  /**
     返回此上下文的显示名称
   */
  String getDisplayName();

  /**
  返回首次加载此上下文时的时间戳
   */
  long getStartupDate();

  /**
   返回父级上下文，如果没有父级，则返回{@code null}
   */
  @Nullable
  ApplicationContext getParent();

  /**
  针对此上下文公开AutowireCapableBeanFactory功能。* <p>应用程序代码通常不使用此功能，除非是为了*初始化存在于应用程序上下文之外的bean实例，*将Spring bean生命周期（全部或部分）应用于它们。* <p>或者，通过{@link ConfigurableApplicationContext}接口公开的内部BeanFactory也提供对{{link AutowireCapableBeanFactory}接口的访问。本方法主要*用作ApplicationContext接口上的便捷特定工具。* <p> <b>注意：从4.2开始，在关闭应用程序上下文之后，此方法将始终抛出IllegalStateException *。</ b>在当前的Spring Framework *版本中，只有可刷新的应用程序上下文才具有这种行为；从4.2开始，*所有应用程序上下文实现都将必须遵守。* @为此上下文返回AutowireCapableBeanFactory *如果上下文不支持{@link AutowireCapableBeanFactory}接口，或者尚不具有支持自动连线功能的bean工厂，则抛出IllegalStateException（例如，如果{@code refresh（）}具有*从未调用过），或者上下文已经关闭* @see ConfigurableApplicationContext＃refresh（）* @see ConfigurableApplicationContext＃getBeanFactory（）* /
   */
  AutowireCapableBeanFactory getAutowireCapableBeanFactory() throws IllegalStateException;

public interface WebApplicationContext extends ApplicationContext {

  /**
  Context属性，用于在成功启动时将根WebApplicationContext绑定到该属性。* <p>注意：如果根上下文的启动失败，则此属性可以包含*异常或错误作为值。使用WebApplicationContextUtils方便*查找根WebApplicationContext。
   */
  String ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE = WebApplicationContext.class.getName() + ".ROOT";

  /**
  请求范围的范围标识符：“ request”。*除了标准范围“ singleton”和“ prototype”之外，还受支持。
   */
  String SCOPE_REQUEST = "request";

  /**
  会话范围的范围标识符：“session”。*除了标准范围“ singleton”和“ prototype”之外，还受支持。
   */
  String SCOPE_SESSION = "session";

  /**
  全局Web应用程序范围的范围标识符：“application”。*除了标准范围“ singleton”和“ prototype”之外，还受支持。
   */
  String SCOPE_APPLICATION = "application";

  /**
  工厂中ServletContext环境Bean的名称
   */
  String SERVLET_CONTEXT_BEAN_NAME = "servletContext";

  /**
  工厂中ServletContext init-params环境Bean的名称
   */
  String CONTEXT_PARAMETERS_BEAN_NAME = "contextParameters";

  /**
  工厂中ServletContext属性环境bean的名称
   */
  String CONTEXT_ATTRIBUTES_BEAN_NAME = "contextAttributes";


  /**
  返回此应用程序的标准Servlet API ServletContext
   */
  @Nullable
  ServletContext getServletContext();
}