spring Autowired 代码注解自动注入源码分析

spring Autowired 代码注解自动注入源码分析

关键流程代码：
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(String, RootBeanDefinition, Object[])
				//找出所有需要依懒注入的字段或者方法参数，保留进缓存
				applyMergedBeanDefinitionPostProcessors(mbd, beanType, beanName);
				mbd.postProcessed = true;
			}
		}

		// Eagerly cache singletons to be able to resolve circular references
		// even when triggered by lifecycle interfaces like BeanFactoryAware.
		boolean earlySingletonExposure = (mbd.isSingleton() && this.allowCircularReferences &&
				isSingletonCurrentlyInCreation(beanName));
		if (earlySingletonExposure) {
			if (logger.isDebugEnabled()) {
				logger.debug("Eagerly caching bean '" + beanName +
						"' to allow for resolving potential circular references");
			}
			addSingletonFactory(beanName, new ObjectFactory() {
				public Object getObject() throws BeansException {
					return getEarlyBeanReference(beanName, mbd, bean);
				}
			});
		}

		// Initialize the bean instance.
		Object exposedObject = bean;
		try {
			//根据上面的查找，在缓存中查找出来，对bean进行填充
			populateBean(beanName, mbd, instanceWrapper);


一阶段：
加载注解声明于代码：org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.AutowiredAnnotationBeanPostProcessor()


二阶段：
定位注解处，进行注入；

注意：org.springframework.util.ReflectionUtils.findMethod(Class<?>, String, Class<?>...)代码处进行该bean类的子类查找，找出所有需要注入的属性（包括子类的属性）；
具体代码如下：

2016-06-14 15:49:54

"main" - Thread t@1
   java.lang.Thread.State: RUNNABLE
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.buildAutowiringMetadata(AutowiredAnnotationBeanPostProcessor.java:327)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.findAutowiringMetadata(AutowiredAnnotationBeanPostProcessor.java:318)
	- locked <4fd2408f> (a java.util.concurrent.ConcurrentHashMap)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessMergedBeanDefinition(AutowiredAnnotationBeanPostProcessor.java:217)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyMergedBeanDefinitionPostProcessors(AbstractAutowireCapableBeanFactory.java:840)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:495)
	- locked <39990cf6> (a java.lang.Object)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
	- locked <6f220804> (a java.util.concurrent.ConcurrentHashMap)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:626)
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
	- locked <233c779c> (a java.lang.Object)
	at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
	at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
	at com.springapp.demo.Main2.main(Main2.java:19)

   Locked ownable synchronizers:
	- None



2016-06-14 13:14:16



"main" - Thread t@1
   java.lang.Thread.State: RUNNABLE
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.buildAutowiringMetadata(AutowiredAnnotationBeanPostProcessor.java:334)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.findAutowiringMetadata(AutowiredAnnotationBeanPostProcessor.java:318)
	- locked <1259f252> (a java.util.concurrent.ConcurrentHashMap)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessMergedBeanDefinition(AutowiredAnnotationBeanPostProcessor.java:217)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyMergedBeanDefinitionPostProcessors(AbstractAutowireCapableBeanFactory.java:840)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:495)
	//在这里开始创建具体的bean
		//具体代码中：org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(String, RootBeanDefinition, BeanWrapper)
						//更具体的代码如下：
						//	if (bp instanceof InstantiationAwareBeanPostProcessor) {
						//			InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp;
						//			if (!ibp.postProcessAfterInstantiation(bw.getWrappedInstance(), beanName)) {
						//				continueWithPropertyPopulation = false;
						//				break;
						//			}
						//		}
						//
						//具体的填充为：org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(String, BeanDefinition, BeanWrapper, PropertyValues)
							//更具体的代码如下：
								// Set our (possibly massaged) deep copy.
								//try {
								//	bw.setPropertyValues(new MutablePropertyValues(deepCopy));
									//org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(PropertyValues, boolean, boolean)
								//}
								//org.springframework.beans.BeanWrapperImpl.setPropertyValue(PropertyTokenHolder, PropertyValue) (这个方法挺长，不过还是容易理解
								//final Method writeMethod = (pd instanceof GenericTypeAwarePropertyDescriptor ?((GenericTypeAwarePropertyDescriptor) pd).getWriteMethodForActualAccess() :)
								//这个方法用于判断到底使用普通的set方法注入，还是别外使用别的方式 ；
								//这个方法用于查找之前需要注入的所有//InjectionMetadataorg.springframework.context.annotation.CommonAnnotationBeanPostProcessor.findResourceMetadata(Class<?>)
								// 关键注入代码是：org.springframework.beans.factory.annotation.InjectionMetadata.inject(Object, String, PropertyValues)
									//可以看见以下两行代码，即是使用了反射注入@autowised bean：
														ReflectionUtils.makeAccessible(field);
														field.set(bean, value);
								//下面几行代码就是注入了：
										try {
											metadata.inject(bean, beanName, pvs);
										}
										catch (Throwable ex) {
											throw new BeanCreationException(beanName, "Injection of resource dependencies failed", ex);
										}
										return pvs;
										
	- locked <5a89a850> (a java.lang.Object)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
	- locked <3894aa0> (a java.util.concurrent.ConcurrentHashMap)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:626)
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
	- locked <2a825030> (a java.lang.Object)
	at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
	at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
	at com.springapp.demo.Main.main(Main.java:20)

   Locked ownable synchronizers:
	- None