我们现在观察doCreateBean(beanName, mbdToUse, args); 源码，其中实现了移除缓存、创建实例、初始化实例等一系列操作，其中在exposedObject = initializeBean(beanName, exposedObject, mbd);中变有我们需要的关键信息。：代码块四
initializeBean(beanName, exposedObject, mbd);这个方法里面有applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName);和applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);两个方法的调用。这里面的原理是获取所有的beanPostProcessors遍历调用其postProcessBeforeInitialization和postProcessAfterInitialization方法。这里我就不过多的赘述了。调试代码我们可以发现后续的调用链如下AbstractAutoProxyCreator#postProcessAfterInitialization-->AbstractAutoProxyCreator#wrapIfNecessary。在这里我们就可以判断其是否拥有增强器来创建代理对象，我们可以通过下面代码来观察其逻辑（增强器便是代理对象的各个方法封装起来的对象）：代码块五
进入代理构建入口Object proxy = createProxy(bean.getClass(), beanName, specificInterceptors, new SingletonTargetSource(bean));以下便是通过默认的GClib来进行对象的一个封装。其代理封装的对象如下：代码块六
/**********************代码块一***********************/
@Test
public void test3() {
AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(AnnotationAopConfig.class); //初始化IOC容器
String[] beanDefinitionNames = applicationContext.getBeanDefinitionNames();
Student student = (Student) applicationContext.getBean("student");//从容器中获取对象
student.innerMethod(); //进行方法调用
applicationContext.close();
}
/**********************代码块二***********************/
public static void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {
/**
* IOC:stepA6-1 获取到所有已经定义了的，需要创建实例的所有实现BeanPostProcessor的类
* org.springframework.context.annotation.internalAutowiredAnnotationProcessor
* org.springframework.context.annotation.internalRequiredAnnotationProcessor
* org.springframework.aop.config.internalAutoProxyCreator
*/
String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);
....
/**
* 分离实现了PriorityOrdered、Ordered和rest接口的BeanPostProcessors
* 按顺序注册BeanPostProcessors
*/
List<String> orderedPostProcessorNames = new ArrayList<>();
List<String> nonOrderedPostProcessorNames = new ArrayList<>();
for (String ppName : postProcessorNames) {
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) { //如果是PriorityOrdered的子类
....
}
else if (beanFactory.isTypeMatch(ppName, Ordered.class)) { //AOP 匹配internalAutoProxyCreator，添加到orderedPostProcessorNames集合当中
orderedPostProcessorNames.add(ppName);
}
else {
nonOrderedPostProcessorNames.add(ppName);
}
}
// 首先, 注册实现PriorityOrdered接口的BeanPostProcessors
sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);
// Next, register the BeanPostProcessors that implement Ordered.
List<BeanPostProcessor> orderedPostProcessors = new ArrayList<>();
for (String ppName : orderedPostProcessorNames) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class); //实例化internalAutoProxyCreator
orderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);//将internalAutoProxyCreator实例放进去
}
}
sortPostProcessors(orderedPostProcessors, beanFactory);
registerBeanPostProcessors(beanFactory, orderedPostProcessors); //将BeanPostProcessor注册到BeanFactory
....
}
/**********************代码块三***********************/
protected Object createBean(String beanName, RootBeanDefinition mbd, @Nullable Object[] args)
throws BeanCreationException {
....
try {
// Give BeanPostProcessors a chance to return a proxy instead of the target bean instance.
//IOC:stepA10 给BeanPostProcessor一个机会返回一个代理实例代替Bean实例
Object bean = resolveBeforeInstantiation(beanName, mbdToUse);
if (bean != null) {
return bean;
}
}
catch (Throwable ex) {
throw new BeanCreationException(mbdToUse.getResourceDescription(), beanName,
"BeanPostProcessor before instantiation of bean failed", ex);
}