接着上一篇我们看看具体是哪里的代码执行了。

1.初始化BeanFactoryPostProcessor

invokeBeanFactoryPostProcessors(beanFactory);-->

PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors());


List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<>();
        for (String postProcessorName : nonOrderedPostProcessorNames) {
    //这里有一个getBean这里进行BeanFactoryPostProcessor的初始化操作 
    nonOrderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
        }

//这里执行BeanFactoryPostProcessor.postProcessBeanFactory
    invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory);

执行BeanDefinitionRegistryPostProcessor.postProcessBeanDefinitionRegistry

    private static void invokeBeanDefinitionRegistryPostProcessors(
            Collection<? extends BeanDefinitionRegistryPostProcessor> postProcessors, BeanDefinitionRegistry registry) {

        for (BeanDefinitionRegistryPostProcessor postProcessor : postProcessors) {
            postProcessor.postProcessBeanDefinitionRegistry(registry);
        }
    }

2.执行BeanFactoryPostProcessor的postProcessBeanFactory

private static void invokeBeanFactoryPostProcessors(
            Collection<? extends BeanFactoryPostProcessor> postProcessors, ConfigurableListableBeanFactory beanFactory) {

        for (BeanFactoryPostProcessor postProcessor : postProcessors) {
            postProcessor.postProcessBeanFactory(beanFactory);
        }
    }

3.初始化BeanPostProcessor。

registerBeanPostProcessors(beanFactory);-->

protected void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory) {
        PostProcessorRegistrationDelegate.registerBeanPostProcessors(beanFactory, this);
    }


    public static void registerBeanPostProcessors(
            ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {
....

    // Now, register all regular BeanPostProcessors.
        List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<>();
        for (String ppName : nonOrderedPostProcessorNames) {
        //同样这里getBean对BeanPostProcessor进行实例化
            BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
            nonOrderedPostProcessors.add(pp);
            if (pp instanceof MergedBeanDefinitionPostProcessor) {
                internalPostProcessors.add(pp);
            }
        }
....
}

4.执行InstantiationAwareBeanPostProcessor.postProcessBeforeInstantiation
这里只以单例为例

AbstractBeanFactory.doGetBean(final String name, @Nullable final Class<T> requiredType,
            @Nullable final Object[] args, boolean typeCheckOnly) throws BeansException {
...
    // Create bean instance.
                if (mbd.isSingleton()) {
                    sharedInstance = getSingleton(beanName, () -> { try { return createBean(beanName, mbd, args); } catch (BeansException ex) { // Explicitly remove instance from singleton cache: It might have been put there // eagerly by the creation process, to allow for circular reference resolution. // Also remove any beans that received a temporary reference to the bean. destroySingleton(beanName); throw ex; } }); ... } 进入createBean Object bean = resolveBeforeInstantiation(beanName, mbdToUse); protected Object resolveBeforeInstantiation(String beanName, RootBeanDefinition mbd) { Object bean = null; if (!Boolean.FALSE.equals(mbd.beforeInstantiationResolved)) { // Make sure bean class is actually resolved at this point. if (!mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) { Class<?> targetType = determineTargetType(beanName, mbd); if (targetType != null) { bean = applyBeanPostProcessorsBeforeInstantiation(targetType, beanName); if (bean != null) { bean = applyBeanPostProcessorsAfterInitialization(bean, beanName); } } } mbd.beforeInstantiationResolved = (bean != null); } return bean; } protected Object applyBeanPostProcessorsBeforeInstantiation(Class<?> beanClass, String beanName) { for (BeanPostProcessor bp : getBeanPostProcessors()) { if (bp instanceof InstantiationAwareBeanPostProcessor) { InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp; Object result = ibp.postProcessBeforeInstantiation(beanClass, beanName); if (result != null) { return result; } } } return null; } 上面已经执行了postProcessBeforeInstantiation 

5.执行bean的构造函数

进入Object beanInstance = doCreateBean(beanName, mbdToUse, args);


if (instanceWrapper == null) {
            //这里面进行初始化
            instanceWrapper = createBeanInstance(beanName, mbd, args);
        }

6.执行
postProcessBeforeInstantiation.postProcessPropertyValues

进入populateBean(beanName, mbd, instanceWrapper);



if (hasInstAwareBpps || needsDepCheck) {
            PropertyDescriptor[] filteredPds = filterPropertyDescriptorsForDependencyCheck(bw, mbd.allowCaching);
            if (hasInstAwareBpps) {
                for (BeanPostProcessor bp : getBeanPostProcessors()) {
                    if (bp instanceof InstantiationAwareBeanPostProcessor) {

//这里执行postProcessBeforeInstantiation.postProcessPropertyValues

                        pvs = ibp.postProcessPropertyValues(pvs, filteredPds, bw.getWrappedInstance(), beanName);
                        if (pvs == null) {
                            return;
                        }
                    }
                }
            }
            if (needsDepCheck) {
                checkDependencies(beanName, mbd, filteredPds, pvs);
            }
        }


applyPropertyValues(beanName, mbd, bw, pvs);

7.为bean注入属性

applyPropertyValues(beanName, mbd, bw, pvs);

8.执行bean实现的有关Aware接口

进入 exposedObject = initializeBean(beanName, exposedObject, mbd); //这里给Aware赋予aware接口的能力 invokeAwareMethods(beanName, bean);

9.执行BeanPostProcessor.postProcessBeforeInitialization

if (mbd == null || !mbd.isSynthetic()) {
            wrappedBean = applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName);
        }



    public Object applyBeanPostProcessorsBeforeInitialization(Object existingBean, String beanName)
            throws BeansException {

        Object result = existingBean;
        for (BeanPostProcessor beanProcessor : getBeanPostProcessors()) {
            Object current = beanProcessor.postProcessBeforeInitialization(result, beanName);
            if (current == null) {
                return result;
            }
            result = current;
        }
        return result;
    }

10.执行@PostConstrut初始化方法

执行CommonAnnotationBeanPostProcessor.postProcessBeforeInitialization具体为什么会调用该方法放在后面统一讲解

11.执行InitializingBean.

进入invokeInitMethods(beanName, wrappedBean, mbd);

protected void invokeInitMethods(String beanName, final Object bean, @Nullable RootBeanDefinition mbd)
            throws Throwable {

        boolean isInitializingBean = (bean instanceof InitializingBean);
        if (isInitializingBean && (mbd == null || !mbd.isExternallyManagedInitMethod("afterPropertiesSet"))) {
            if (logger.isDebugEnabled()) {
                logger.debug("Invoking afterPropertiesSet() on bean with name '" + beanName + "'");
            }
            if (System.getSecurityManager() != null) {
                try {
                    AccessController.doPrivileged((PrivilegedExceptionAction<Object>) () -> { ((InitializingBean) bean).afterPropertiesSet(); return null; }, getAccessControlContext()); } catch (PrivilegedActionException pae) { throw pae.getException(); } } else { //这里调用 ((InitializingBean) bean).afterPropertiesSet(); } } if (mbd != null) { String initMethodName = mbd.getInitMethodName(); if (StringUtils.hasLength(initMethodName) && !(isInitializingBean && "afterPropertiesSet".equals(initMethodName)) && !mbd.isExternallyManagedInitMethod(initMethodName)) { invokeCustomInitMethod(beanName, bean, mbd); } } }

12.执行xml的init-method

if (mbd != null) {
            String initMethodName = mbd.getInitMethodName();
            if (StringUtils.hasLength(initMethodName) &&
                    !(isInitializingBean && "afterPropertiesSet".equals(initMethodName)) &&
                    !mbd.isExternallyManagedInitMethod(initMethodName)) {
                invokeCustomInitMethod(beanName, bean, mbd);
            }
        }

13.执行BeanPostProcessor.postProcessAfterInitialization

if (mbd == null || !mbd.isSynthetic()) {
            wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);
        }
@Override
    public Object applyBeanPostProcessorsAfterInitialization(Object existingBean, String beanName)
            throws BeansException {

        Object result = existingBean;
        for (BeanPostProcessor beanProcessor : getBeanPostProcessors()) {
            Object current = beanProcessor.postProcessAfterInitialization(result, beanName);
            if (current == null) {
                return result;
            }
            result = current;
        }
        return result;
    }

以上的代码以AbstractApplicationContext。。refresh和AbstractBeanFactory.doGetBean为入口一步步跟均能找到。

上篇讲解了spring生命周期，这篇讲解了spring哪里具体实现。下一篇就讲解应用了，注解如何实现，例如@Configutation,@Import,@PostConstrut等。