解析
- 在使用 Spring AOP 技术的时候会有下面这段代码在 xml 配置文件中出现,来达到 Spring 支持 AOP
<aop:aspectj-autoproxy/>Copy to clipboardErrorCopied
- 源码阅读目标找到了,那么怎么去找入口或者对这句话的标签解析方法呢?项目中使用搜索
这样就找到了具体解析方法了
org.springframework.aop.config.AspectJAutoProxyBeanDefinitionParser
- 类图
@Override @Nullable public BeanDefinition parse(Element element, ParserContext parserContext) { // 注册 <aop:aspectj-autoproxy/> AopNamespaceUtils.registerAspectJAnnotationAutoProxyCreatorIfNecessary(parserContext, element); // 子类解析 extendBeanDefinition(element, parserContext); return null; } Copy to clipboardErrorCopied
/** * 注册 <aop:aspectj-autoproxy/> * @param parserContext * @param sourceElement */ public static void registerAspectJAnnotationAutoProxyCreatorIfNecessary( ParserContext parserContext, Element sourceElement) { // 注册或者升级bean BeanDefinition beanDefinition = AopConfigUtils.registerAspectJAnnotationAutoProxyCreatorIfNecessary( parserContext.getRegistry(), parserContext.extractSource(sourceElement)); // proxy-target-class 和 expose-proxy 标签处理 useClassProxyingIfNecessary(parserContext.getRegistry(), sourceElement); // 注册组件并且交给监听器 registerComponentIfNecessary(beanDefinition, parserContext); } Copy to clipboardErrorCopied
- org.springframework.aop.config.AopConfigUtils.registerAspectJAnnotationAutoProxyCreatorIfNecessary(org.springframework.beans.factory.support.BeanDefinitionRegistry, java.lang.Object)
@Nullable public static BeanDefinition registerAspectJAnnotationAutoProxyCreatorIfNecessary( BeanDefinitionRegistry registry, @Nullable Object source) { // 注册或者升级 AspectJ return registerOrEscalateApcAsRequired(AnnotationAwareAspectJAutoProxyCreator.class, registry, source); } Copy to clipboardErrorCopied
- org.springframework.aop.config.AopConfigUtils.registerOrEscalateApcAsRequired
/** * 注册或者升级 bean * @param cls 类 * @param registry 注册器 * @param source 源类 * @return */ @Nullable private static BeanDefinition registerOrEscalateApcAsRequired( Class<?> cls, BeanDefinitionRegistry registry, @Nullable Object source) { Assert.notNull(registry, "BeanDefinitionRegistry must not be null"); // 判断注册器是否包含org.springframework.aop.config.internalAutoProxyCreator if (registry.containsBeanDefinition(AUTO_PROXY_CREATOR_BEAN_NAME)) { // 获取注册器 BeanDefinition apcDefinition = registry.getBeanDefinition(AUTO_PROXY_CREATOR_BEAN_NAME); // 创建新的bean对象 if (!cls.getName().equals(apcDefinition.getBeanClassName())) { int currentPriority = findPriorityForClass(apcDefinition.getBeanClassName()); int requiredPriority = findPriorityForClass(cls); if (currentPriority < requiredPriority) { apcDefinition.setBeanClassName(cls.getName()); } } // 即将创建的Bean对象和当前的注册器相同返回null return null; } RootBeanDefinition beanDefinition = new RootBeanDefinition(cls); beanDefinition.setSource(source); // 设置加载顺序 beanDefinition.getPropertyValues().add("order", Ordered.HIGHEST_PRECEDENCE); beanDefinition.setRole(BeanDefinition.ROLE_INFRASTRUCTURE); // 注册bean定义 registry.registerBeanDefinition(AUTO_PROXY_CREATOR_BEAN_NAME, beanDefinition); return beanDefinition; } Copy to clipboardErrorCopied
org.springframework.aop.config.AopNamespaceUtils.useClassProxyingIfNecessary
/** * proxy-target-class 和 expose-proxy 标签处理 */ private static void useClassProxyingIfNecessary(BeanDefinitionRegistry registry, @Nullable Element sourceElement) { if (sourceElement != null) { // 处理 proxy-target-class boolean proxyTargetClass = Boolean.parseBoolean(sourceElement.getAttribute(PROXY_TARGET_CLASS_ATTRIBUTE)); if (proxyTargetClass) { AopConfigUtils.forceAutoProxyCreatorToUseClassProxying(registry); } // 处理 expose-proxy boolean exposeProxy = Boolean.parseBoolean(sourceElement.getAttribute(EXPOSE_PROXY_ATTRIBUTE)); if (exposeProxy) { AopConfigUtils.forceAutoProxyCreatorToExposeProxy(registry); } } } Copy to clipboardErrorCopied
- org.springframework.aop.config.AopConfigUtils.forceAutoProxyCreatorToUseClassProxying
public static void forceAutoProxyCreatorToUseClassProxying(BeanDefinitionRegistry registry) { if (registry.containsBeanDefinition(AUTO_PROXY_CREATOR_BEAN_NAME)) { BeanDefinition definition = registry.getBeanDefinition(AUTO_PROXY_CREATOR_BEAN_NAME); definition.getPropertyValues().add("proxyTargetClass", Boolean.TRUE); } } Copy to clipboardErrorCopied
- forceAutoProxyCreatorToExposeProxy方法就不贴出代码了,操作和forceAutoProxyCreatorToUseClassProxying一样都是将读取到的数据放入 bean 对象作为一个属性存储
总结
- 实现org.springframework.beans.factory.xml.BeanDefinitionParser接口的类,多用于对 xml 标签的解析,并且入口为parse方法,如果是一个 bean 对象通常会和 Spring 监听器一起出现
