spring源码分析：spring生命周期二

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。