spring源码学习系列4-3种常用的自动代理创建器 博客分类： spring spring

3种自动代理器是
AnnotationAwareAspectJAutoProxyCreator-<aop:aspectj-autoproxy />

AbstractAdvisorAutoProxyCreator-<aop:config>

InfrastructureAdvisorAutoProxyCreator-<tx:annotation-driven/>

他们在Spring中注册的beanName都是

public static final String AUTO_PROXY_CREATOR_BEAN_NAME =
			"org.springframework.aop.config.internalAutoProxyCreator"

它们的优先级从上到下,即3者都配置了,默认注册AnnotationAwareAspectJAutoProxyCreator。那<tx:annotation-driven/>如何解析呢




<aop:aspectj-autoproxy /> - AopNamespaceHandler

该配置就是定义了一个AnnotationAwareAspectJAutoProxyCreator（BeanPostProcessor）的bean

InstantiationModelAwarePointcutAdvisor
AspectJExpressionPointcut
AspectJMethodBeforeAdvice,AspectJAfterAdvice,AspectJAfterReturningAdvice,AspectJAfterThrowingAdvice,AspectJAroundAdvice


该<aop>配置，不会定义Advisor,定义Advisor是在后置处理器(AnnotationAwareAspectJAutoProxyCreator)生成代理时动态创建的

AnnotationAwareAspectJAutoProxyCreator#findCandidateAdvisors

@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.
		advisors.addAll(this.aspectJAdvisorsBuilder.buildAspectJAdvisors());
		return advisors;
	}

this.aspectJAdvisorsBuilder.buildAspectJAdvisors()生成InstantiationModelAwarePointcutAdvisor,表示注解或Apect类型的切面。

相关切面元素:
AspectJExpressionPointcut
(ReflectiveAspectJAdvisorFactory#getPointcut)

AspectJMethodBeforeAdvice,AspectJAfterAdvice,AspectJAfterReturningAdvice,AspectJAfterThrowingAdvice,AspectJAroundAdvice
(ReflectiveAspectJAdvisorFactory#getAdvice)


this.aspectJAdvisorsBuilder.buildAspectJAdvisors()具体如何设计实现注解的切面这里不做扩展，感兴趣的可以通过代码查看










<aop:config/> - AopNamespaceHandler

spring中的该配置实际上就是注册了几个beanDefinition

AspectJAwareAdvisorAutoProxyCreator -BeanPostProcessor

AspectJExpressionPointcut - Pointcut

DefaultBeanFactoryPointcutAdvisor - Advisor


至于怎么实现解析注册的，感兴趣的可查看源码
ConfigBeanDefinitionParser#parse

public BeanDefinition parse(Element element, ParserContext parserContext) {
		CompositeComponentDefinition compositeDef =
				new CompositeComponentDefinition(element.getTagName(), parserContext.extractSource(element));
		parserContext.pushContainingComponent(compositeDef);

		configureAutoProxyCreator(parserContext, element);

		List<Element> childElts = DomUtils.getChildElements(element);
		for (Element elt: childElts) {
			String localName = parserContext.getDelegate().getLocalName(elt);
			if (POINTCUT.equals(localName)) {
				parsePointcut(elt, parserContext);
			}
			else if (ADVISOR.equals(localName)) {
				parseAdvisor(elt, parserContext);
			}
			else if (ASPECT.equals(localName)) {
				parseAspect(elt, parserContext);
			}
		}

		parserContext.popAndRegisterContainingComponent();
		return null;
	}

<tx:annotation-driven transaction-manager="transactionManager" /> - TxNamespaceHandler

spring中的该配置实际上就是注册了几个beanDefinition

InfrastructureAdvisorAutoProxyCreator

TransactionAttributeSourcePointcut Pointcut

TransactionInterceptor - MethodInterceptor(advice)

TransactionAttributeSourceAdvisor - Advisor(持有advice,pointcut)

TransactionInterceptor主要是处理事务的增强,这里不对其扩展
TransactionInterceptor#invoke

public Object invoke(final MethodInvocation invocation) throws Throwable {
		// Work out the target class: may be {@code null}.
		// The TransactionAttributeSource should be passed the target class
		// as well as the method, which may be from an interface.
		Class<?> targetClass = (invocation.getThis() != null ? AopUtils.getTargetClass(invocation.getThis()) : null);

		// Adapt to TransactionAspectSupport's invokeWithinTransaction...
		return invokeWithinTransaction(invocation.getMethod(), targetClass, new InvocationCallback() {
			public Object proceedWithInvocation() throws Throwable {
				return invocation.proceed();
			}
		});
	}

参考:<spring源码学习系列1.2-spring事务代理深入分析2>
http://newjava-sina-cn.iteye.com/blog/2422939