标签:form 代码 UI 一点 try ida ast startup enabled
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前言
在上一篇中有一处代码是BeanDefiniton注册的入口,我们回顾一下。
首先我们回顾两点,1. 发起注册的地方;2. 注册的实现类
我们先看第一点,在上篇博文中我们讲了Bean的解析,在DefaultBeanDefinitonDocumentReader类的processBeanDefiniton()方法中,其中一个是去完成BeanDefiniton的载入,另一个是完成注册。我们看下代码:
DefaultBeanDefinitionDocumentReader类的processBeanDefinition方法
protected void processBeanDefinition(Element ele, BeanDefinitionParserDelegate delegate) { //解析方法
BeanDefinitionHolder bdHolder = delegate.parseBeanDefinitionElement(ele); if (bdHolder != null) { bdHolder = delegate.decorateBeanDefinitionIfRequired(ele, bdHolder); try { // 注册方法
BeanDefinitionReaderUtils.registerBeanDefinition(bdHolder, getReaderContext().getRegistry()); } catch (BeanDefinitionStoreException ex) { getReaderContext().error("Failed to register bean definition with name ‘" + bdHolder.getBeanName() + "‘", ele, ex); } getReaderContext().fireComponentRegistered(new BeanComponentDefinition(bdHolder)); } }
现在我们找到了BeanDefiniton的注册入口,我们知道BeanDefinitonHolder=BeanDefiniton+BeanName,来看下registerBeanDefinition的代码:
BeanDefinitionReaderUtils类的registerBeanDefinition方法
public static void registerBeanDefinition( BeanDefinitionHolder definitionHolder, BeanDefinitionRegistry registry) throws BeanDefinitionStoreException { // 根据beanName注册BeanDefinition String beanName = definitionHolder.getBeanName(); registry.registerBeanDefinition(beanName, definitionHolder.getBeanDefinition()); // 如果有别名,注册别名
String[] aliases = definitionHolder.getAliases(); if (aliases != null) { for (String alias : aliases) { registry.registerAlias(beanName, alias); } } }
我们找registerBeanDefinition的实现类,会发现有三个实现类,那么具体取哪个呢?还记得我们最初容器建立的时候用的什么容器吗?我们回顾下代码:
AbstractRefreshableApplicationContext类的refreshBeanFactory方法
protected final void refreshBeanFactory() throws BeansException { if (hasBeanFactory()) { destroyBeans(); closeBeanFactory(); } try { DefaultListableBeanFactory beanFactory = createBeanFactory(); beanFactory.setSerializationId(getId()); customizeBeanFactory(beanFactory); loadBeanDefinitions(beanFactory); synchronized (this.beanFactoryMonitor) { this.beanFactory = beanFactory; } } catch (IOException ex) { throw new ApplicationContextException("I/O error parsing bean definition source for " + getDisplayName(), ex); } }
而且,我们看下DefaultListableBeanFactory实现了BeanDefinitionRegistry接口,这个接口就是定义注册的。并且这个类中有这么一个HashMap,存放beandefiniton的地方。
//--------------------------------------------------------------------- // Implementation of BeanDefinitionRegistry interface //--------------------------------------------------------------------- @Override public void registerBeanDefinition(String beanName, BeanDefinition beanDefinition) throws BeanDefinitionStoreException { Assert.hasText(beanName, "Bean name must not be empty"); Assert.notNull(beanDefinition, "BeanDefinition must not be null"); if (beanDefinition instanceof AbstractBeanDefinition) { try { ((AbstractBeanDefinition) beanDefinition).validate(); } catch (BeanDefinitionValidationException ex) { throw new BeanDefinitionStoreException(beanDefinition.getResourceDescription(), beanName, "Validation of bean definition failed", ex); } } BeanDefinition oldBeanDefinition; oldBeanDefinition = this.beanDefinitionMap.get(beanName); if (oldBeanDefinition != null) { if (!isAllowBeanDefinitionOverriding()) { throw new BeanDefinitionStoreException(beanDefinition.getResourceDescription(), beanName, "Cannot register bean definition [" + beanDefinition + "] for bean ‘" + beanName + "‘: There is already [" + oldBeanDefinition + "] bound."); } else if (oldBeanDefinition.getRole() < beanDefinition.getRole()) { // e.g. was ROLE_APPLICATION, now overriding with ROLE_SUPPORT or ROLE_INFRASTRUCTURE if (this.logger.isWarnEnabled()) { this.logger.warn("Overriding user-defined bean definition for bean ‘" + beanName + "‘ with a framework-generated bean definition: replacing [" + oldBeanDefinition + "] with [" + beanDefinition + "]"); } } else if (!beanDefinition.equals(oldBeanDefinition)) { if (this.logger.isInfoEnabled()) { this.logger.info("Overriding bean definition for bean ‘" + beanName + "‘ with a different definition: replacing [" + oldBeanDefinition + "] with [" + beanDefinition + "]"); } } else { if (this.logger.isDebugEnabled()) { this.logger.debug("Overriding bean definition for bean ‘" + beanName + "‘ with an equivalent definition: replacing [" + oldBeanDefinition + "] with [" + beanDefinition + "]"); } } this.beanDefinitionMap.put(beanName, beanDefinition); } else { if (hasBeanCreationStarted()) { // Cannot modify startup-time collection elements anymore (for stable iteration) synchronized (this.beanDefinitionMap) { this.beanDefinitionMap.put(beanName, beanDefinition); List<String> updatedDefinitions = new ArrayList<String>(this.beanDefinitionNames.size() + 1); updatedDefinitions.addAll(this.beanDefinitionNames); updatedDefinitions.add(beanName); this.beanDefinitionNames = updatedDefinitions; if (this.manualSingletonNames.contains(beanName)) { Set<String> updatedSingletons = new LinkedHashSet<String>(this.manualSingletonNames); updatedSingletons.remove(beanName); this.manualSingletonNames = updatedSingletons; } } } else { // Still in startup registration phase this.beanDefinitionMap.put(beanName, beanDefinition); this.beanDefinitionNames.add(beanName); this.manualSingletonNames.remove(beanName); } this.frozenBeanDefinitionNames = null; } if (oldBeanDefinition != null || containsSingleton(beanName)) { resetBeanDefinition(beanName); } }
到这里,代码就完成了IOC容器的初始化过程。此时,在使用的IOC容器DefaultListableBeanFactory中已经建立了整个Bean的配置信息,而且这些BeanDefinition已经可以被容器使用了。他们都在beanDefinitionMap中被检索和使用。
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Spring IOC容器的初始化-(三)BeanDefinition的注册
标签:form 代码 UI 一点 try ida ast startup enabled
原文地址:http://www.cnblogs.com/whx7762/p/7792881.html