Spring-framework应用程序启动loadtime源码分析笔记（二）——@Transactional

@Transactional标识类或方法，使方法被执行时使用事务方式执行，这里只讨论PROXY方法增强方法。使用@EnableTransactionManagement，默认model=AdviceMode.PROXY，通过@Import(TransactionManagementConfigurationSelector.class)来判断在加载时注册PROXY不是ASPECTJ相关类。PROXY相关类有AutoProxyRegistrar和ProxyTransactionManagementConfiguration。AutoProxyRegistrar作用是通过EnableTransactionManagement.proxyTargetClass值判断使用CGLIB或是Java interface-based proxies。使用Java interface-based proxies时AnnotationAwareAspectJAutoProxyCreator，AnnotationAwareAspectJAutoProxyCreator是一个BeanPostProcessor实现类。使用CGLIB也是注册AnnotationAwareAspectJAutoProxyCreator并且将proxyTargetClass=true，如下AopConfigUtils.forceAutoProxyCreatorToUseClassProxying()

AnnotationAwareAspectJAutoProxyCreator.wrapIfNecessary()

AnnotationAwareAspectJAutoProxyCreator是一个BeanPostProcessor实现类，它的相应方法会在容器管理每个对象实例化不同阶段会执行。wrapIfNecessary()方法在postProcessAfterInitialization()方法调用，主要是判断实例化对象是否容器所有Advisor所要作用对象，如@Transactional标识的方法或类的对象匹配BeanFactoryTransactionAttributeSourceAdvisor。

AnnotationTransactionAttributeSource.determineTransactionAttribute()

判断传入的方法是否含@Transactional标识，返回TransactionAttribute

下面是AnnotationAwareAspectJAutoProxyCreator(AbstractAutoProxyCreator).wrapIfNecessary()的stack

Thread [main] (Suspended (breakpoint at line 348 in AbstractAutoProxyCreator))

owns: ConcurrentHashMap<K,V> (id=2343)

owns: Object (id=2107)

AnnotationAwareAspectJAutoProxyCreator(AbstractAutoProxyCreator).wrapIfNecessary(Object, String, Object) line: 348

AnnotationAwareAspectJAutoProxyCreator(AbstractAutoProxyCreator).postProcessAfterInitialization(Object, String) line: 298

DefaultListableBeanFactory(AbstractAutowireCapableBeanFactory).applyBeanPostProcessorsAfterInitialization(Object, String) line: 435

DefaultListableBeanFactory(AbstractAutowireCapableBeanFactory).initializeBean(String, Object, RootBeanDefinition) line: 1721

DefaultListableBeanFactory(AbstractAutowireCapableBeanFactory).doCreateBean(String, RootBeanDefinition, Object[]) line: 581

DefaultListableBeanFactory(AbstractAutowireCapableBeanFactory).createBean(String, RootBeanDefinition, Object[]) line: 498

DefaultListableBeanFactory(AbstractBeanFactory).lambda$doGetBean$0(String, RootBeanDefinition, Object[]) line: 305

48361312.getObject() line: not available

DefaultListableBeanFactory(DefaultSingletonBeanRegistry).getSingleton(String, ObjectFactory<?>) line: 233

DefaultListableBeanFactory(AbstractBeanFactory).doGetBean(String, Class<T>, Object[], boolean) line: 303

DefaultListableBeanFactory(AbstractBeanFactory).getBean(String, Class<T>) line: 198

CommonAnnotationBeanPostProcessor.autowireResource(BeanFactory, CommonAnnotationBeanPostProcessor$LookupElement, String) line: 512

CommonAnnotationBeanPostProcessor.getResource(CommonAnnotationBeanPostProcessor$LookupElement, String) line: 483

CommonAnnotationBeanPostProcessor$ResourceElement.getResourceToInject(Object, String) line: 617

CommonAnnotationBeanPostProcessor$ResourceElement(InjectionMetadata$InjectedElement).inject(Object, String, PropertyValues) line: 172

InjectionMetadata.inject(Object, String, PropertyValues) line: 89

CommonAnnotationBeanPostProcessor.postProcessPropertyValues(PropertyValues, PropertyDescriptor[], Object, String) line: 317

DefaultListableBeanFactory(AbstractAutowireCapableBeanFactory).populateBean(String, RootBeanDefinition, BeanWrapper) line: 1353

DefaultListableBeanFactory(AbstractAutowireCapableBeanFactory).doCreateBean(String, RootBeanDefinition, Object[]) line: 579