spring容器生命周期执行原理探究

一、api分析

首先看下AutowireCapableBeanFactory接口简单api,有下面接口可以简单的看到api中包含了创建bean，初始化，以及初始化前后的后置处理器api
初始化：
Object initializeBean(Object var1, String var2)
初始化前：
Object applyBeanPostProcessorsBeforeInitialization(Object var1, String var2)
初始化后：
Object applyBeanPostProcessorsAfterInitialization(Object var1, String var2)

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;

    @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;
}

2、具体执行过程

• 具体执行过程在AbstractAutowireCapableBeanFactory类内
  在初始化方法内，会先后执行applyBeanPostProcessorsBeforeInitialization和applyBeanPostProcessorsAfterInitialization
  

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• applyBeanPostProcessorsBeforeInitialization和applyBeanPostProcessorsAfterInitialization执行过程会获取容器中的BeanPostProcessor依次执行
  

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• 实际初始化方法利用反射执行
  初始化方法定义可以通过
  生命周期-InitializingBean和DisposableBean、生命周期-@PostConstruct&@PreDestroy
  

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