Spring---事务-@Transactional

/**
     *  【代理对象创建】
     *
     *      org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator
     *          org.springframework.beans.factory.config.BeanPostProcessor implementation that wraps each eligible bean with an AOP proxy, BeanPostProcessor的实现类，包装了每个有资格代理的Bean，
     *              delegating to specified interceptors before invoking the bean itself. 委托指定的interceptors调用；
     *
     *          public abstract class AbstractAutoProxyCreator extends ProxyProcessorSupport implements SmartInstantiationAwareBeanPostProcessor, BeanFactoryAware {
     *
     *              @Nullable
     *              protected static final Object[] DO_NOT_PROXY = null;
     *
     *              @Override
     *              public Object postProcessAfterInitialization(@Nullable Object bean, String beanName) {
     * 		            if (bean != null) {
     * 			            Object cacheKey = getCacheKey(bean.getClass(), beanName);
     * 			            if (this.earlyProxyReferences.remove(cacheKey) != bean) {
     * 				            return wrapIfNecessary(bean, beanName, cacheKey);
     *                      }
     *                  }
     * 		            return bean;
     *              }
     *
     *              protected Object wrapIfNecessary(Object bean, String beanName, Object cacheKey) {
     *                  ...
     *                  // Create proxy if we have advice.
     * 		            Object[] specificInterceptors = getAdvicesAndAdvisorsForBean(bean.getClass(), beanName, null); // 获取当前Bean所有的AOP advices
     * 		            if (specificInterceptors != DO_NOT_PROXY) { // 当前Bean有aop advice， 执行aop织入
     * 			            this.advisedBeans.put(cacheKey, Boolean.TRUE);
     * 			            Object proxy = createProxy(bean.getClass(), beanName, specificInterceptors, new SingletonTargetSource(bean));
     * 			            this.proxyTypes.put(cacheKey, proxy.getClass());
     * 			            return proxy;
     *                  }
     *
     * 		            this.advisedBeans.put(cacheKey, Boolean.FALSE);
     * 		            return bean;
     *              }
     *
     *              protected Object createProxy(Class<?> beanClass, @Nullable String beanName, @Nullable Object[] specificInterceptors, TargetSource targetSource) {
     *                  ...
     *                  ProxyFactory proxyFactory = new ProxyFactory();
     *                  ...
     *                  return proxyFactory.getProxy(getProxyClassLoader());
     *              }
     *          }
     *
     *      org.springframework.aop.framework.autoproxy.AbstractAdvisorAutoProxyCreator
     *          Generic auto proxy creator that builds AOP proxies for specific beans based on detected Advisors for each bean. 为每个Bean检测到的advisor 创建代理对象的 创建者；
     *          Subclasses may override the findCandidateAdvisors() method to return a custom list of Advisors applying to any object. 子类 可能覆盖findCandidateAdvisors方法 返回advisors；
     *          Advisors or advices requiring ordering should implement the org.springframework.core.Ordered interface. advisors要求顺序的需要实现Ordered接口；
     *          This class sorts Advisors by Ordered order value. 该类将对实现Ordered接口的advice 进行排序；
     *          Advisors that don't implement the Ordered interface will be considered as unordered; 未实现Ordered的advice将视为无序；
     *              they will appear at the end of the advisor chain in undefined order.
     *
     *          public abstract class AbstractAdvisorAutoProxyCreator extends AbstractAutoProxyCreator {
     *              protected List findCandidateAdvisors() {}
     *              protected List sortAdvisors(List advisors) {}
     *          }
     *
     *      org.springframework.aop.aspectj.autoproxy.AspectJAwareAdvisorAutoProxyCreator
     *          public class AspectJAwareAdvisorAutoProxyCreator extends AbstractAdvisorAutoProxyCreator {
     *
     *          }
     *
     *      org.springframework.aop.aspectj.annotation.AnnotationAwareAspectJAutoProxyCreator
     *          AspectJAwareAdvisorAutoProxyCreator subclass that processes all AspectJ annotation aspects in the current application context, as well as Spring Advisors.
     *          AspectJAwareAdvisorAutoProxyCreator子类处理 所有的在当前应用中的AspectJ注解 和 Spring的advisors;
     *
     *          public class AnnotationAwareAspectJAutoProxyCreator extends AspectJAwareAdvisorAutoProxyCreator {
     *
     *          }
     *
     *      创建思路：BeanPostProcessor#postProcessAfterInitialization
     *
     *      org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory#initializeBean
     *
     *      ->
     *
     *      org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory#applyBeanPostProcessorsAfterInitialization
     *
     *      ->
     *
     *      org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator#postProcessAfterInitialization{
     *
     *          public Object postProcessAfterInitialization(@Nullable Object bean, String beanName) {
     *              ...
     *              return wrapIfNecessary(bean, beanName, cacheKey);
     *              ...
     *          }
     *
     *          protected Object wrapIfNecessary(Object bean, String beanName, Object cacheKey) {
     *              ...
     *              Object proxy = createProxy(bean.getClass(), beanName, specificInterceptors, new SingletonTargetSource(bean));
     *              ...
     *          }
     *
     *          protected Object createProxy(Class<?> beanClass, @Nullable String beanName, @Nullable Object[] specificInterceptors, TargetSource targetSource) {
     *              ...
     *              ProxyFactory proxyFactory = new ProxyFactory();
     *              ...
     *              return proxyFactory.getProxy(getProxyClassLoader());
     *          }
     *      }
     *
     *      BeanPostProcessor : org.springframework.aop.aspectj.annotation.AnnotationAwareAspectJAutoProxyCreator
     *
     *      advice : org.springframework.transaction.interceptor.BeanFactoryTransactionAttributeSourceAdvisor
     *
     */