spring－aop

一 类结构

类结构图.png

• AbstractAutoProxyCreator模版方法查找aop配置bean，并创建代理，实现BeanPostProcessor接口，插入到spring 容器bean初始化流程中
• AbstractAdvisorAutoProxyCreator缓存aop相关配置bean，并提供查找和目标bean代理匹配处理
• AspectJAwareAdvisorAutoProxyCreator支持aop代理排序
• AnnotationAwareAspectJAutoProxyCreator支持注解代理处理

二 aop创建流程

aop创建.png

2.1 注解的aop创建

• AnnotationAwareAspectJAutoProxyCreator通过实现接口findCandidateAdvisors对aspectj的注解进行处理

protected List findCandidateAdvisors() {
    //获取xml标签定义的aop相关配置bean
    List advisors = super.findCandidateAdvisors();
//获取注解标记的aop相关配置bean
    advisors.addAll(this.aspectJAdvisorsBuilder.buildAspectJAdvisors());
    return advisors;
}

• 获取包含Aspect注解或者是ajc编译器编译的类

public List buildAspectJAdvisors() {
    List aspectNames = null;

    synchronized (this) {
        aspectNames = this.aspectBeanNames;
        if (aspectNames == null) {
            List advisors = new LinkedList();
            aspectNames = new LinkedList();
            String[] beanNames =
                    BeanFactoryUtils.beanNamesForTypeIncludingAncestors(this.beanFactory, Object.class, true, false);//获取所有bean
            for (String beanName : beanNames) {
                if (!isEligibleBean(beanName)) {
                    continue;
                }
                // 获取bean类型
                Class beanType = this.beanFactory.getType(beanName);
                if (beanType == null) {
                    continue;
                }
//包含Aspect注解或者是ajc编译器编译的类
                if (this.advisorFactory.isAspect(beanType)) {
                    aspectNames.add(beanName);
                    AspectMetadata amd = new AspectMetadata(beanType, beanName);
                    if (amd.getAjType().getPerClause().getKind() == PerClauseKind.SINGLETON) {
                        MetadataAwareAspectInstanceFactory factory =
                                new BeanFactoryAspectInstanceFactory(this.beanFactory, beanName);
                        List classAdvisors = this.advisorFactory.getAdvisors(factory);
                        if (this.beanFactory.isSingleton(beanName)) {
                            this.advisorsCache.put(beanName, classAdvisors);
                        }
                        else {
                            this.aspectFactoryCache.put(beanName, factory);
                        }
                        advisors.addAll(classAdvisors);
                    }
                    else {
                        // Per target or per this.
                        if (this.beanFactory.isSingleton(beanName)) {
                            throw new IllegalArgumentException("Bean with name '" + beanName +
                                    "' is a singleton, but aspect instantiation model is not singleton");
                        }
                        MetadataAwareAspectInstanceFactory factory =
                                new PrototypeAspectInstanceFactory(this.beanFactory, beanName);
                        this.aspectFactoryCache.put(beanName, factory);
                        advisors.addAll(this.advisorFactory.getAdvisors(factory));
                    }
                }
            }
            this.aspectBeanNames = aspectNames;
            return advisors;
        }
    }

    if (aspectNames.isEmpty()) {
        return Collections.emptyList();
    }
    List advisors = new LinkedList();
    for (String aspectName : aspectNames) {
        List cachedAdvisors = this.advisorsCache.get(aspectName);
        if (cachedAdvisors != null) {
            advisors.addAll(cachedAdvisors);
        }
        else {
            MetadataAwareAspectInstanceFactory factory = this.aspectFactoryCache.get(aspectName);
            advisors.addAll(this.advisorFactory.getAdvisors(factory));
        }
    }
    return advisors;
}