Spring|Spring AOP核心源码解读 SpringAOP核心源码解读

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回顾bean容器的初始化过程

1、this.refresh(); 配置初始化后执行
2、this.finishBeanFactoryInitialization(beanFactory); 初始化所有单例
3、beanFactory.preInstantiateSingletons(); 初始化所有非懒加载的单例对象
4、this.getBean(beanName); --doGetBean 判断是否初始化过，没初始化的话执行后面的创建动作
5、this.createBean(beanName, mbd, args); --this.doCreateBean(beanName, mbdToUse, args); 单例情况下调用此方法
6、BeanWrapper instanceWrapper = this.createBeanInstance(beanName, mbd, args); 创建bean转换为wrapper方法
7、this.populateBean(beanName, mbd, instanceWrapper); 设置属性
8、exposedObject = this.initializeBean(beanName, exposedObject, mbd); 执行初始化方法
9、this.invokeAwareMethods(beanName, bean); 检查aware依赖
10、wrappedBean = this.applyBeanPostProcessorsBeforeInitialization(bean, beanName); bean前置加强
11、 this.invokeInitMethods(beanName, wrappedBean, mbd); 执行init方法
12、wrappedBean = this.applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName); 后置加强
13、bean正常使用
14、bean销毁

核心源码 1、启动@EnableAspectJAutoProxy时，会往IOC容器中注入AnnotationAwareAspectJAutoProxyCreator.class

@EnableAspectJAutoProxy @Import({AspectJAutoProxyRegistrar.class}) AopConfigUtils.registerAspectJAnnotationAutoProxyCreatorIfNecessary(registry); registerOrEscalateApcAsRequired(AnnotationAwareAspectJAutoProxyCreator.class, registry, source); registry.registerBeanDefinition("org.springframework.aop.config.internalAutoProxyCreator", beanDefinition); beanId:org.springframework.aop.config.internalAutoProxyCreator class:AnnotationAwareAspectJAutoProxyCreator.class

2、AnnotationAwareAspectJAutoProxyCreator.class类图最终属于BeanPostProcessor的子类

>>>>AspectJAwareAdvisorAutoProxyCreator >>>>>>>>AbstractAdvisorAutoProxyCreator >>>>>>>>>>>>AbstractAutoProxyCreator extends ProxyProcessorSupport implements SmartInstantiationAwareBeanPostProcessor, BeanFactoryAwareSmartInstantiationAwareBeanPostProcessor.class >>>>InstantiationAwareBeanPostProcessor extends BeanPostProcessor

3、BeanPostProcessor 拥有前置和后置通知，可看到子类AbstractAutoProxyCreator，可以看到AOP是后置代理起到了作用

public Object postProcessBeforeInitialization(Object bean, String beanName) { return bean; }public Object postProcessAfterInitialization(@Nullable Object bean, String beanName) throws BeansException { if (bean != null) { Object cacheKey = this.getCacheKey(bean.getClass(), beanName); if (!this.earlyProxyReferences.contains(cacheKey)) { return this.wrapIfNecessary(bean, beanName, cacheKey); } }return bean; }

4、this.wrapIfNecessary(bean, beanName, cacheKey);

//判断是否需要增加 protected boolean isInfrastructureClass(Class beanClass) { boolean retVal = Advice.class.isAssignableFrom(beanClass) || Pointcut.class.isAssignableFrom(beanClass) || Advisor.class.isAssignableFrom(beanClass) || AopInfrastructureBean.class.isAssignableFrom(beanClass); if (retVal && this.logger.isTraceEnabled()) { this.logger.trace("Did not attempt to auto-proxy infrastructure class [" + beanClass.getName() + "]"); }return retVal; } Object[] specificInterceptors = this.getAdvicesAndAdvisorsForBean(bean.getClass(), beanName, (TargetSource)null); //需要增强的话，则创建JDK动态代理或cglib动态代理 Object proxy = this.createProxy(bean.getClass(), beanName, specificInterceptors, new SingletonTargetSource(bean)); proxyFactory.getProxy(this.getProxyClassLoader()); this.createAopProxy().getProxy(classLoader); //如果请求是接口，则调用JdkDynamicAopProxy，否则调用ObjenesisCglibAopProxy public AopProxy createAopProxy(AdvisedSupport config) throws AopConfigException { if (!config.isOptimize() && !config.isProxyTargetClass() && !this.hasNoUserSuppliedProxyInterfaces(config)) { return new JdkDynamicAopProxy(config); } else { Class targetClass = config.getTargetClass(); if (targetClass == null) { throw new AopConfigException("TargetSource cannot determine target class: Either an interface or a target is required for proxy creation."); } else { return (AopProxy)(!targetClass.isInterface() && !Proxy.isProxyClass(targetClass) ? new ObjenesisCglibAopProxy(config) : new JdkDynamicAopProxy(config)); } } }

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