SpringAOP[7]-基础的自动代理(AnnotationAwareAspectJAutoProxyCreator)
原文:SpringAOP联盟(7)-基础的自动代理(AnnotationAwareAspectJAutoProxyCreator) - 简书 (jianshu.com)
DefaultAdvisorAutoProxyCreator
和AspectJAwareAdvisorAutoProxyCreator
均实现了AbstractAdvisorAutoProxyCreator
接口。
自动代理实现的核心:在Spring容器中,bean找到“合格”Advisor。
在上文中可知,寻找Bean上“合格”的Advisors是AbstractAutoProxyCreator定义的抽象getAdvicesAndAdvisorsForBean
方法。具体逻辑由子类实现。
而真正实现被代理类
与增强器
解耦的自动代理器
,实际上是AbstractAdvisorAutoProxyCreator
去完成的。
AbstractAdvisorAutoProxyCreator寻找“合格”Advisor,那么它眼中的合格是什么样子的呢?
- 子类是否允许:子类可实现
isEligibleAdvisorBean(beanName)
方法,对Spring容器中所有的Advisor
类进行初次筛选。 - Advisor是否切入了Bean:每个Advisor(增强器)会根据Pointcut(切点)使用ClassFilter判断被代理类是否满足规则;使用MethodMatcher判断被代理类是否有方法满足规则;
当然在获得Bean上合格
的Advisors后,Spring允许子类进行扩展
和排序
。
![](https://img2020.cnblogs.com/blog/1374196/202111/1374196-20211116032828696-1001911012.webp)
InfrastructureAdvisorAutoProxyCreator——基建的自动生成器
测试方法
@Slf4j public class TService { public void run1() { System.out.println("This is a run1() Method!"); } @Transactional public void say() { log.info("说话..."); } }
@Configuration @EnableTransactionManagement//注册了ProxyTransactionManagementConfiguration public class MyConfig { @Bean("tService") public TService tService() { return new TService(); } }
public class TestSpringProxy { public static void main(String[] args) { AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(MyConfig.class); //可以使用@Primary指定元素,或直接使用name名获取。 TService bean = (TService)applicationContext.getBean("tService"); bean.say(); } }
源码分析
InfrastructureAdvisorAutoProxyCreator
实现了isEligibleAdvisorBean(beanName)
方法,即检索出Spring
中符合“要求”所有的Advisor
。public class InfrastructureAdvisorAutoProxyCreator extends AbstractAdvisorAutoProxyCreator { @Nullable private ConfigurableListableBeanFactory beanFactory; @Override protected void initBeanFactory(ConfigurableListableBeanFactory beanFactory) { super.initBeanFactory(beanFactory); this.beanFactory = beanFactory; } //在Spring容器中获取Advisor的Bean,然后判断是否是内部的bean对象。 @Override protected boolean isEligibleAdvisorBean(String beanName) { return (this.beanFactory != null && this.beanFactory.containsBeanDefinition(beanName) && this.beanFactory.getBeanDefinition(beanName).getRole() == BeanDefinition.ROLE_INFRASTRUCTURE); } }
而实际上,事务的Advisor和Advice均由Spring完成注册。
@Configuration public class ProxyTransactionManagementConfiguration extends AbstractTransactionManagementConfiguration { //注册了Advisor @Bean(name = TransactionManagementConfigUtils.TRANSACTION_ADVISOR_BEAN_NAME) @Role(BeanDefinition.ROLE_INFRASTRUCTURE) //声明的role为基础类(Spring内部使用的类) public BeanFactoryTransactionAttributeSourceAdvisor transactionAdvisor() { BeanFactoryTransactionAttributeSourceAdvisor advisor = new BeanFactoryTransactionAttributeSourceAdvisor(); advisor.setTransactionAttributeSource(transactionAttributeSource()); advisor.setAdvice(transactionInterceptor()); if (this.enableTx != null) { advisor.setOrder(this.enableTx.<Integer>getNumber("order")); } return advisor; } @Bean @Role(BeanDefinition.ROLE_INFRASTRUCTURE) public TransactionAttributeSource transactionAttributeSource() { return new AnnotationTransactionAttributeSource(); } //注册了Advice @Bean @Role(BeanDefinition.ROLE_INFRASTRUCTURE) public TransactionInterceptor transactionInterceptor() { TransactionInterceptor interceptor = new TransactionInterceptor(); interceptor.setTransactionAttributeSource(transactionAttributeSource()); if (this.txManager != null) { interceptor.setTransactionManager(this.txManager); } return interceptor; } }