public List<Advisor> findAdvisorBeans() { // Determine list of advisor bean names, if not cached already. // 1.确认advisor的beanName列表，优先从缓存中拿 String[] advisorNames = this.cachedAdvisorBeanNames; if (advisorNames == null) { // Do not initialize FactoryBeans here: We need to leave all regular beans // uninitialized to let the auto-proxy creator apply to them! // 1.1 如果缓存为空，则获取class类型为Advisor的所有bean名称 advisorNames = BeanFactoryUtils.beanNamesForTypeIncludingAncestors( this.beanFactory, Advisor.class, true, false); this.cachedAdvisorBeanNames = advisorNames; } if (advisorNames.length == 0) { return new ArrayList<>(); }
// 2.遍历处理advisorNames List<Advisor> advisors = new ArrayList<>(); for (String name : advisorNames) { if (isEligibleBean(name)) { // 2.1 跳过当前正在创建的advisor if (this.beanFactory.isCurrentlyInCreation(name)) { if (logger.isTraceEnabled()) { logger.trace("Skipping currently created advisor '" + name + "'"); } } else { try { // 2.2 通过beanName获取对应的bean对象，并添加到advisors advisors.add(this.beanFactory.getBean(name, Advisor.class)); } catch (BeanCreationException ex) { Throwable rootCause = ex.getMostSpecificCause(); if (rootCause instanceof BeanCurrentlyInCreationException) { BeanCreationException bce = (BeanCreationException) rootCause; String bceBeanName = bce.getBeanName(); if (bceBeanName != null && this.beanFactory.isCurrentlyInCreation(bceBeanName)) { if (logger.isTraceEnabled()) { logger.trace("Skipping advisor '" + name + "' with dependency on currently created bean: " + ex.getMessage()); } // Ignore: indicates a reference back to the bean we're trying to advise. // We want to find advisors other than the currently created bean itself. continue; } } throw ex; } } } } // 3.返回符合条件的advisor列表 return advisors; }
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/** * 找到符合条件的Advisor * @return */ @Override protected List<Advisor> findCandidateAdvisors() { // Add all the Spring advisors found according to superclass rules. List<Advisor> advisors = super.findCandidateAdvisors(); // Build Advisors for all AspectJ aspects in the bean factory. if (this.aspectJAdvisorsBuilder != null) { advisors.addAll(this.aspectJAdvisorsBuilder.buildAspectJAdvisors()); } return advisors; }
public List<Advisor> buildAspectJAdvisors() { List<String> aspectNames = this.aspectBeanNames;
// 1.如果aspectNames为空，则进行解析 if (aspectNames == null) { synchronized (this) { aspectNames = this.aspectBeanNames; if (aspectNames == null) { List<Advisor> advisors = new ArrayList<>(); aspectNames = new ArrayList<>(); // 1.1 获取所有的beanName String[] beanNames = BeanFactoryUtils.beanNamesForTypeIncludingAncestors( this.beanFactory, Object.class, true, false); // 1.2 循环遍历所有的beanName，找出对应的增强方法 for (String beanName : beanNames) { // 1.3 不合法的beanName则跳过，默认返回true，子类可以覆盖实现，AnnotationAwareAspectJAutoProxyCreator // 实现了自己的逻辑，支持使用includePatterns进行筛选 if (!isEligibleBean(beanName)) { continue; } // We must be careful not to instantiate beans eagerly as in this case they // would be cached by the Spring container but would not have been weaved. // 获取beanName对应的bean的类型 Class<?> beanType = this.beanFactory.getType(beanName); if (beanType == null) { continue; } // 1.4 如果beanType存在Aspect注解则进行处理 if (this.advisorFactory.isAspect(beanType)) { // 将存在Aspect注解的beanName添加到aspectNames列表 aspectNames.add(beanName); // 新建切面元数据 AspectMetadata amd = new AspectMetadata(beanType, beanName); if (amd.getAjType().getPerClause().getKind() == PerClauseKind.SINGLETON) { // 使用BeanFactory和beanName创建一个BeanFactoryAspectInstanceFactory，主要用来创建切面对象实例 MetadataAwareAspectInstanceFactory factory = new BeanFactoryAspectInstanceFactory(this.beanFactory, beanName); // 1.5 解析标记AspectJ注解中的增强方法********************* List<Advisor> classAdvisors = this.advisorFactory.getAdvisors(factory); // 1.6 放到缓存中 if (this.beanFactory.isSingleton(beanName)) { // 如果beanName是单例则直接将解析的增强方法放到缓存 this.advisorsCache.put(beanName, classAdvisors); } else { // 如果不是单例，则将factory放到缓存，之后可以通过factory来解析增强方法 this.aspectFactoryCache.put(beanName, factory); } // 1.7 将解析的增强器添加到advisors advisors.addAll(classAdvisors); } else { // Per target or per this. if (this.beanFactory.isSingleton(beanName)) { // 名称为beanName的Bean是单例，但切面实例化模型不是单例，则抛异常 throw new IllegalArgumentException("Bean with name '" + beanName + "' is a singleton, but aspect instantiation model is not singleton"); } MetadataAwareAspectInstanceFactory factory = new PrototypeAspectInstanceFactory(this.beanFactory, beanName); // 将factory放到缓存，之后可以通过factory来解析增强方法 this.aspectFactoryCache.put(beanName, factory); // 解析标记AspectJ注解中的增强方法，并添加到advisors中 advisors.addAll(this.advisorFactory.getAdvisors(factory)); } } } // 1.9 将解析出来的切面beanName放到缓存aspectBeanNames this.aspectBeanNames = aspectNames; return advisors; } } }
// We need to wrap the MetadataAwareAspectInstanceFactory with a decorator // so that it will only instantiate once. // 4.使用装饰器包装MetadataAwareAspectInstanceFactory，以便它只实例化一次。 MetadataAwareAspectInstanceFactory lazySingletonAspectInstanceFactory = newLazySingletonAspectInstanceFactoryDecorator(aspectInstanceFactory);
// 2.是否需要延迟实例化 if (aspectInstanceFactory.getAspectMetadata().isLazilyInstantiated()) { // Static part of the pointcut is a lazy type. Pointcut preInstantiationPointcut = Pointcuts.union( aspectInstanceFactory.getAspectMetadata().getPerClausePointcut(), this.declaredPointcut);
// Make it dynamic: must mutate from pre-instantiation to post-instantiation state. // If it's not a dynamic pointcut, it may be optimized out // by the Spring AOP infrastructure after the first evaluation. this.pointcut = new PerTargetInstantiationModelPointcut( this.declaredPointcut, preInstantiationPointcut, aspectInstanceFactory); this.lazy = true; } else { // A singleton aspect. this.pointcut = this.declaredPointcut; this.lazy = false; // 3.实例化增强器：根据注解中的信息初始化对应的增强器 this.instantiatedAdvice = instantiateAdvice(this.declaredPointcut); } }
