以接口肢解bean factory，源码没那么神秘
<blockquote><p>本来昨天在看 spring frame的八股， 看到了IOC部分，但是实在看不懂是什么东西，讲是讲源码部分，但又不完全讲，我想着那我要不自己看一下源码</p>
</blockquote>
<p>这是我画的Bean Factory的大致关系图</p>
<p><img src="https://img2024.cnblogs.com/blog/3642195/202506/3642195-20250630172127581-1833129013.png"></p>
<p>删去了bean别名管理接口（AliasRegistry）和bean定义接口（BeanDefinitionRegistry）避免复杂理解</p>
<p><code>BeanFactory</code>有三个子类<code>ListableBeanFactory</code> ，<code>HierarchicalBeanFactory</code>，<code>ConfigurableBeanFactory</code> ，<code>AutowireCapableBeanFactory</code> 。</p>
<p>我们先来看看<code>BeanFactory</code> 只实现了IOC 容器的基本行为规范，好比是让需求方提出对目标的需求。</p>
<pre><code class="language-java">public interface BeanFactory {
//与FactoryBean创建的bean区分开来, 若命名的bean是FactoryBean，
//则获取将返回Factory，而不是Factory返回的实例。
String FACTORY_BEAN_PREFIX = "&";
Object getBean(String var1) throws BeansException;
<T> T getBean(String var1, Class<T> var2) throws BeansException;
Object getBean(String var1, Object... var2) throws BeansException;
<T> T getBean(Class<T> var1) throws BeansException;
<T> T getBean(Class<T> var1, Object... var2) throws BeansException;
<T> ObjectProvider<T> getBeanProvider(Class<T> var1);
<T> ObjectProvider<T> getBeanProvider(ResolvableType var1);
boolean containsBean(String var1);
boolean isSingleton(String var1) throws NoSuchBeanDefinitionException;
boolean isPrototype(String var1) throws NoSuchBeanDefinitionException;
boolean isTypeMatch(String var1, ResolvableType var2) throws NoSuchBeanDefinitionException;
boolean isTypeMatch(String var1, Class<?> var2) throws NoSuchBeanDefinitionException;
@Nullable
Class<?> getType(String var1) throws NoSuchBeanDefinitionException;
@Nullable
Class<?> getType(String var1, boolean var2) throws NoSuchBeanDefinitionException;
String[] getAliases(String var1);
}
</code></pre>
<p><code>ListableBeanFactory</code> 定义了Factory Bean的可枚举性，适用于批量操作 bean 的场景</p>
<pre><code class="language-java">public interface ListableBeanFactory extends BeanFactory {
boolean containsBeanDefinition(String var1);
int getBeanDefinitionCount();
String[] getBeanDefinitionNames();
<T> ObjectProvider<T> getBeanProvider(Class<T> var1, boolean var2);
<T> ObjectProvider<T> getBeanProvider(ResolvableType var1, boolean var2);
String[] getBeanNamesForType(ResolvableType var1);
String[] getBeanNamesForType(ResolvableType var1, boolean var2, boolean var3);
String[] getBeanNamesForType(@Nullable Class<?> var1);
String[] getBeanNamesForType(@Nullable Class<?> var1, boolean var2, boolean var3);
<T> Map<String, T> getBeansOfType(@Nullable Class<T> var1) throws BeansException;
<T> Map<String, T> getBeansOfType(@Nullable Class<T> var1, boolean var2, boolean var3) throws BeansException;
String[] getBeanNamesForAnnotation(Class<? extends Annotation> var1);
Map<String, Object> getBeansWithAnnotation(Class<? extends Annotation> var1) throws BeansException;
@Nullable
<A extends Annotation> A findAnnotationOnBean(String var1, Class<A> var2) throws NoSuchBeanDefinitionException;
@Nullable
<A extends Annotation> A findAnnotationOnBean(String var1, Class<A> var2, boolean var3) throws NoSuchBeanDefinitionException;
}
</code></pre>
<p><code>HierarchicalBeanFactory</code> 定义了Bean Factory的分层能力</p>
<p>之前还不知道Bean Factory可以有父子容器区分<br>
<em>与继承相似，子类可以调用父类的方法。父类不能调用子类的方法</em></p>
<p>Spring MVC 有以下分层</p>
<ul>
<li>根上下文（ContextLoaderListener 或 Spring Boot 创建）作为父容器。</li>
</ul>
<p>如服务层、数据访问层和基础设施 bean（DataSource）。</p>
<ul>
<li>DispatcherServlet 的上下文作为子容器。</li>
</ul>
<p>定义 Web 层特定 bean，如控制器、HandlerMapping 等。</p>
<pre><code class="language-java">public interface HierarchicalBeanFactory extends BeanFactory {
@Nullable
BeanFactory getParentBeanFactory();
boolean containsLocalBean(String var1);
}
</code></pre>
<p><code>ConfigurableBeanFactory</code> 定义了自定义Bean工厂的能力 ， 自定义类加载器、beany定义、作用域、依赖关系。</p>
<pre><code class="language-java">
public interface ConfigurableBeanFactory extends HierarchicalBeanFactory, SingletonBeanRegistry {
// 自定义类加载器
void setBeanClassLoader(@Nullable ClassLoader var1);
@Nullable
ClassLoader getBeanClassLoader();
void setTempClassLoader(@Nullable ClassLoader var1);
@Nullable
ClassLoader getTempClassLoader();
// bean 定义
void setCacheBeanMetadata(boolean var1);
boolean isCacheBeanMetadata();
BeanDefinition getMergedBeanDefinition(String var1) throws NoSuchBeanDefinitionException;
boolean isFactoryBean(String var1) throws NoSuchBeanDefinitionException;
// 作用域
void registerScope(String var1, Scope var2);
String[] getRegisteredScopeNames();
@Nullable
Scope getRegisteredScope(String var1);
// 依赖关系
void registerDependentBean(String var1, String var2);
String[] getDependentBeans(String var1);
String[] getDependenciesForBean(String var1);
......
......
}
</code></pre>
<p><code>AutowireCapableBeanFactory</code> 实现了Bean自动装配能力</p>
<pre><code class="language-java">public interface AutowireCapableBeanFactory extends BeanFactory {
int AUTOWIRE_NO = 0;
int AUTOWIRE_BY_NAME = 1;
int AUTOWIRE_BY_TYPE = 2;
int AUTOWIRE_CONSTRUCTOR = 3;
/** @deprecated */
@Deprecated
int AUTOWIRE_AUTODETECT = 4;
String ORIGINAL_INSTANCE_SUFFIX = ".ORIGINAL";
<T> T createBean(Class<T> var1) throws BeansException;
void autowireBean(Object var1) throws BeansException;
Object configureBean(Object var1, String var2) throws BeansException;
Object createBean(Class<?> var1, int var2, boolean var3) throws BeansException;
Object autowire(Class<?> var1, int var2, boolean var3) throws BeansException;
void autowireBeanProperties(Object var1, int var2, boolean var3) throws BeansException;
void applyBeanPropertyValues(Object var1, String var2) throws BeansException;
Object initializeBean(Object var1, String var2) throws BeansException;
Object applyBeanPostProcessorsBeforeInitialization(Object var1, String var2) throws BeansException;
Object applyBeanPostProcessorsAfterInitialization(Object var1, String var2) throws BeansException;
void destroyBean(Object var1);
<T> NamedBeanHolder<T> resolveNamedBean(Class<T> var1) throws BeansException;
Object resolveBeanByName(String var1, DependencyDescriptor var2) throws BeansException;
@Nullable
Object resolveDependency(DependencyDescriptor var1, @Nullable String var2) throws BeansException;
@Nullable
Object resolveDependency(DependencyDescriptor var1, @Nullable String var2, @Nullable Set<String> var3, @Nullable TypeConverter var4) throws BeansException;
}
</code></pre>
<p>看完了这些接口类和接口方法，对IOC容器有了更扩展一些的理解</p>
<p>其实源码还是挺容易看的，先通过一个类向上找到基类，再往下看详细的接口类，实现类。 对其有一个全局的理解</p><br><br>
来源：https://www.cnblogs.com/many-bucket/p/18956769
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