<aop:config>標簽解析

aop名稱空間的解析器是AopNamespaceHandler

// 這里我們可以看到注冊了幾個解析器，重點關注ConfigBeanDefinitionParser

在ConfigBeanDefinitionParser的parse方法中對aop:config下面的三個直接子標簽pointcut、advisor、aspect分別進行解析

// 注冊AnnotationAwareAspectJAutoProxyCreator或AspectJAwareAdvisorAutoProxyCreator
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); } }

pointcut標簽解析

private AbstractBeanDefinition parsePointcut(Element pointcutElement, ParserContext parserContext) {String id = pointcutElement.getAttribute(ID);String expression = pointcutElement.getAttribute(EXPRESSION);AbstractBeanDefinition pointcutDefinition = null;try {this.parseState.push(new PointcutEntry(id));
　　　　　　　// 創建BeanDefinition，下邊詳解 pointcutDefinition = createPointcutDefinition(expression); pointcutDefinition.setSource(parserContext.extractSource(pointcutElement)); String pointcutBeanName = id; if (StringUtils.hasText(pointcutBeanName)) {
　　　　　　　　　// 這里是注冊bean parserContext.getRegistry().registerBeanDefinition(pointcutBeanName, pointcutDefinition); } else { pointcutBeanName = parserContext.getReaderContext().registerWithGeneratedName(pointcutDefinition); } parserContext.registerComponent( new PointcutComponentDefinition(pointcutBeanName, pointcutDefinition, expression)); } finally { this.parseState.pop(); } return pointcutDefinition; } protected AbstractBeanDefinition createPointcutDefinition(String expression) {RootBeanDefinition beanDefinition = new RootBeanDefinition(AspectJExpressionPointcut.class);beanDefinition.setScope(BeanDefinition.SCOPE_PROTOTYPE);beanDefinition.setSynthetic(true);beanDefinition.getPropertyValues().add(EXPRESSION, expression);return beanDefinition;}

我們可以看到RootBeanDefinition的beanClass是AspectJExpressionPointcut，也就是getBean時會實例化AspectJExpressionPointcut，并且為其設置了屬性值expression如execution(* com.wjz.service.*.*(..))

我們來看一下AspectJExpressionPointcut的繼承結構。這個類同時實現了ClassFilter和MethodMatcher接口執行類匹配和方法匹配邏輯。它有一個expression屬性設置表達式，AspectJ最終會把該表達式解析成一個PointcutExpression對象執行相關的語義。后文詳解

aspect標簽解析

?aspect標簽的解析要相對復雜一些，解析它下面的所有通知子標簽（aop:before、aop:after等標簽）

　　　　　　　String aspectId = aspectElement.getAttribute(ID);String aspectName = aspectElement.getAttribute(REF);
// 獲得所有的通知子標簽NodeList nodeList = aspectElement.getChildNodes();boolean adviceFoundAlready = false;for (int i = 0; i < nodeList.getLength(); i++) {Node node = nodeList.item(i);
　　　　　　　　 // 判斷是否是通知標簽如before，after-returning if (isAdviceNode(node, parserContext)) { if (!adviceFoundAlready) { adviceFoundAlready = true; if (!StringUtils.hasText(aspectName)) { parserContext.getReaderContext().error( "<aspect> tag needs aspect bean reference via 'ref' attribute when declaring advices.", aspectElement, this.parseState.snapshot()); return; } beanReferences.add(new RuntimeBeanReference(aspectName)); }
　　　　　　　　　　　　// 解析并注冊通知子標簽，后文詳解 AbstractBeanDefinition advisorDefinition = parseAdvice( aspectName, i, aspectElement, (Element) node, parserContext, beanDefinitions, beanReferences); beanDefinitions.add(advisorDefinition); } } AspectComponentDefinition aspectComponentDefinition = createAspectComponentDefinition( aspectElement, aspectId, beanDefinitions, beanReferences, parserContext); parserContext.pushContainingComponent(aspectComponentDefinition); List<Element> pointcuts = DomUtils.getChildElementsByTagName(aspectElement, POINTCUT); for (Element pointcutElement : pointcuts) { parsePointcut(pointcutElement, parserContext); } parserContext.popAndRegisterContainingComponent(); private AbstractBeanDefinition parseAdvice(String aspectName, int order, Element aspectElement, Element adviceElement, ParserContext parserContext,List<BeanDefinition> beanDefinitions, List<BeanReference> beanReferences) {try {this.parseState.push(new AdviceEntry(parserContext.getDelegate().getLocalName(adviceElement)));// 通知標簽的方法屬性（method屬性）會被解析成一個MethodLocatingFactoryBean類型的bean，并設置了methodName屬性值
　　　　　　　// 為AspectJMethodBeforeAdvice等的構造函數的形參作準備
RootBeanDefinition methodDefinition = new RootBeanDefinition(MethodLocatingFactoryBean.class); methodDefinition.getPropertyValues().add("targetBeanName", aspectName); methodDefinition.getPropertyValues().add("methodName", adviceElement.getAttribute("method")); methodDefinition.setSynthetic(true); // 創建AspectInstanceFactory的一個實例，為AspectJMethodBeforeAdvice等的構造函數的形參作準備 RootBeanDefinition aspectFactoryDef = new RootBeanDefinition(SimpleBeanFactoryAwareAspectInstanceFactory.class);aspectFactoryDef.getPropertyValues().add("aspectBeanName", aspectName);aspectFactoryDef.setSynthetic(true);// 準備AspectJMethodBeforeAdvice等的構造函數，后文詳解AbstractBeanDefinition adviceDef = createAdviceDefinition(adviceElement, parserContext, aspectName, order, methodDefinition, aspectFactoryDef,beanDefinitions, beanReferences);// 解析通知子標簽為AspectJPointcutAdvisor對象RootBeanDefinition advisorDefinition = new RootBeanDefinition(AspectJPointcutAdvisor.class);advisorDefinition.setSource(parserContext.extractSource(adviceElement));
　　　　　　　// 設置AspectJPointcutAdvisor中的AbstractAspectJAdvice的構造函數參數信息advisorDefinition.getConstructorArgumentValues().addGenericArgumentValue(adviceDef);if (aspectElement.hasAttribute(ORDER_PROPERTY)) { advisorDefinition.getPropertyValues().add( ORDER_PROPERTY, aspectElement.getAttribute(ORDER_PROPERTY)); } // 注冊通知子標簽 parserContext.getReaderContext().registerWithGeneratedName(advisorDefinition); return advisorDefinition; } finally { this.parseState.pop(); } } private AbstractBeanDefinition createAdviceDefinition(Element adviceElement, ParserContext parserContext, String aspectName, int order,RootBeanDefinition methodDef, RootBeanDefinition aspectFactoryDef,List<BeanDefinition> beanDefinitions, List<BeanReference> beanReferences) {// getAdviceClass()方法獲得AspectJMethodBeforeAdvice、AspectJAfterReturningAdvice等RootBeanDefinition adviceDefinition = new RootBeanDefinition(getAdviceClass(adviceElement, parserContext));adviceDefinition.setSource(parserContext.extractSource(adviceElement));// 添加屬性值adviceDefinition.getPropertyValues().add(ASPECT_NAME_PROPERTY, aspectName);adviceDefinition.getPropertyValues().add(DECLARATION_ORDER_PROPERTY, order);if (adviceElement.hasAttribute(RETURNING)) {adviceDefinition.getPropertyValues().add(RETURNING_PROPERTY, adviceElement.getAttribute(RETURNING));}if (adviceElement.hasAttribute(THROWING)) { adviceDefinition.getPropertyValues().add( THROWING_PROPERTY, adviceElement.getAttribute(THROWING)); } if (adviceElement.hasAttribute(ARG_NAMES)) { adviceDefinition.getPropertyValues().add( ARG_NAMES_PROPERTY, adviceElement.getAttribute(ARG_NAMES)); } 　　　　　// 準備AspectJMethodBeforeAdvice等構造函數所需的參數，為構造函數反射得到AspectJMethodBeforeAdvice做準備 ConstructorArgumentValues cav = adviceDefinition.getConstructorArgumentValues(); cav.addIndexedArgumentValue(METHOD_INDEX, methodDef); 　　　　　// 獲得pointcut-ref屬性值 Object pointcut = parsePointcutProperty(adviceElement, parserContext); if (pointcut instanceof BeanDefinition) { cav.addIndexedArgumentValue(POINTCUT_INDEX, pointcut); beanDefinitions.add((BeanDefinition) pointcut); } else if (pointcut instanceof String) { RuntimeBeanReference pointcutRef = new RuntimeBeanReference((String) pointcut); cav.addIndexedArgumentValue(POINTCUT_INDEX, pointcutRef); beanReferences.add(pointcutRef); } cav.addIndexedArgumentValue(ASPECT_INSTANCE_FACTORY_INDEX, aspectFactoryDef); return adviceDefinition; }

AspectJMethodBeforeAdvice等的構造函數為

?advisor標簽解析

private void parseAdvisor(Element advisorElement, ParserContext parserContext) {
　　　　　// 創建advisor標簽對應的BeanDefinition,后文詳解AbstractBeanDefinition advisorDef = createAdvisorBeanDefinition(advisorElement, parserContext);String id = advisorElement.getAttribute(ID);try {this.parseState.push(new AdvisorEntry(id));String advisorBeanName = id;
　　　　　　　// 注冊bean　 if (StringUtils.hasText(advisorBeanName)) { parserContext.getRegistry().registerBeanDefinition(advisorBeanName, advisorDef); } else { advisorBeanName = parserContext.getReaderContext().registerWithGeneratedName(advisorDef); } 　　　　　　　// 獲得pointcut-ref屬性值，添加屬性 Object pointcut = parsePointcutProperty(advisorElement, parserContext); if (pointcut instanceof BeanDefinition) { advisorDef.getPropertyValues().add(POINTCUT, pointcut); parserContext.registerComponent( new AdvisorComponentDefinition(advisorBeanName, advisorDef, (BeanDefinition) pointcut)); } else if (pointcut instanceof String) { advisorDef.getPropertyValues().add(POINTCUT, new RuntimeBeanReference((String) pointcut)); parserContext.registerComponent( new AdvisorComponentDefinition(advisorBeanName, advisorDef)); } } finally { this.parseState.pop(); } } private AbstractBeanDefinition createAdvisorBeanDefinition(Element advisorElement, ParserContext parserContext) {
　　　　　// getBean時實例化一個DefaultBeanFactoryPointcutAdvisorRootBeanDefinition advisorDefinition = new RootBeanDefinition(DefaultBeanFactoryPointcutAdvisor.class);advisorDefinition.setSource(parserContext.extractSource(advisorElement));String adviceRef = advisorElement.getAttribute(ADVICE_REF);if (!StringUtils.hasText(adviceRef)) {parserContext.getReaderContext().error("'advice-ref' attribute contains empty value.", advisorElement, this.parseState.snapshot());}else { advisorDefinition.getPropertyValues().add( ADVICE_BEAN_NAME, new RuntimeBeanNameReference(adviceRef)); } if (advisorElement.hasAttribute(ORDER_PROPERTY)) { advisorDefinition.getPropertyValues().add( ORDER_PROPERTY, advisorElement.getAttribute(ORDER_PROPERTY)); } return advisorDefinition; }

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轉載于:https://www.cnblogs.com/BINGJJFLY/p/7452703.html

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