IOC：前面都是对bean定义的处理，postProcess已经实例化了。 解析bean的时候，把需要依赖注入的字段和方法，在postProcessMergedBeanDefinition方法中加到AutowiredAnnotationBeanPostProcessor的变量中，然后在AutowiredAnnotationBeanPostProcessor的作为入口，去依赖注入字段和方法。 protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) { if (beanFactory.containsBean(CONVERSION_SERVICE_BEAN_NAME) && beanFactory.isTypeMatch(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class)) { beanFactory.setConversionService(beanFactory.getBean(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class)); // 实例化一个转换器ConversionService } String[] weaverAwareNames = beanFactory.getBeanNamesForType(LoadTimeWeaverAware.class, false, false); for (String weaverAwareName : weaverAwareNames) { getBean(weaverAwareName); // 没用， } beanFactory.preInstantiateSingletons(); //IOC } public void preInstantiateSingletons() throws BeansException { List<String> beanNames; synchronized (this.beanDefinitionMap) { //所有的beanDefinition，也就是bean的定义信息 beanNames = new ArrayList<String>(this.beanDefinitionNames); //所有的bean的名字 } for (String beanName : beanNames) {//实例化所有的bean RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName); // 合并功能，父子合并了的。 if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) { //不是抽象的，不是懒加载的，是单利，才会去实例化。 if (isFactoryBean(beanName)) {//实现了FactoryBean接口 final FactoryBean<?> factory = (FactoryBean<?>) getBean(FACTORY_BEAN_PREFIX + beanName); boolean isEagerInit; if (System.getSecurityManager() != null && factory instanceof SmartFactoryBean) {//实现了SmartFactoryBean接口 isEagerInit = AccessController.doPrivileged(new PrivilegedAction<Boolean>() { @Override public Boolean run() { return ((SmartFactoryBean<?>) factory).isEagerInit(); //调用这个bean的isEagerInit方法，返回true就实例化， } }, getAccessControlContext()); } else { isEagerInit = (factory instanceof SmartFactoryBean && ((SmartFactoryBean<?>) factory).isEagerInit()); //调用这个bean的isEagerInit方法，返回true就实例化， } if (isEagerInit) {//返回true就实例化， getBean(beanName); //实例化 } } else {//没有实现了FactoryBean接口， getBean(beanName); } } } } 解析有父类的bean，就是合并子类和父类的信息，涉及到子类覆盖父类。 protected RootBeanDefinition getMergedLocalBeanDefinition(String beanName) throws BeansException { RootBeanDefinition mbd = this.mergedBeanDefinitions.get(beanName); // 先从缓存中拿 if (mbd != null) { return mbd; } return getMergedBeanDefinition(beanName, getBeanDefinition(beanName)); } <bean id="parent" class="com.zhuguang.jack.testbean.Parent" abstract="true"> </bean> <bean id="son" class="com.zhuguang.jack.testbean.Son" parent="parent"> </bean> 父类是用来继承的公共部分，不会被实例化。 protected RootBeanDefinition getMergedBeanDefinition(String beanName, BeanDefinition bd, BeanDefinition containingBd)throws BeanDefinitionStoreException {//beanName是bean的名字，bd是bean的定义 synchronized (this.mergedBeanDefinitions) { //mergedBeanDefinitions 是缓存， RootBeanDefinition mbd = null; if (containingBd == null) { mbd = this.mergedBeanDefinitions.get(beanName); } if (mbd == null) { if (bd.getParentName() == null) { // bean没有父类，直接初始化一个RootBeanDefinition if (bd instanceof RootBeanDefinition) { mbd = ((RootBeanDefinition) bd).cloneBeanDefinition(); //也是调用 new RootBeanDefinition(bd); } else { mbd = new RootBeanDefinition(bd);//bd是bean的定义信息，mbd是子类，bd是父类，这里做一个拷贝，是为了不污染db，而是使用重新初始化的mbd。 } } else { // bean有父类，要加载父类的信息 BeanDefinition pbd; try { String parentBeanName = transformedBeanName(bd.getParentName()); //获取父亲的名字， if (!beanName.equals(parentBeanName)) { //跟父的名字不一样， pbd = getMergedBeanDefinition(parentBeanName); //父类的bean定义，父类在有父类继续调用。 } } mbd = new RootBeanDefinition(pbd); //pbd是父类，构造父类 mbd.overrideFrom(bd);//bd是bean的定义信息，mbd是父类，bd是子类，子类覆盖父类的信息， } if (containingBd == null && isCacheBeanMetadata() && isBeanEligibleForMetadataCaching(beanName)) { this.mergedBeanDefinitions.put(beanName, mbd); //加到缓存 } } return mbd; } } getBean(beanName); protected <T> T doGetBean(final String name, final Class<T> requiredType, final Object[] args, boolean typeCheckOnly)throws BeansException { final String beanName = transformedBeanName(name); Object bean; //单利缓存中获取 Object sharedInstance = getSingleton(beanName); if (sharedInstance != null && args == null) { bean = getObjectForBeanInstance(sharedInstance, name, beanName, null); } else { if (isPrototypeCurrentlyInCreation(beanName)) {//已经创建了 throw new BeanCurrentlyInCreationException(beanName); } BeanFactory parentBeanFactory = getParentBeanFactory();//父类容器，从父类容器获取bean。 if (parentBeanFactory != null && !containsBeanDefinition(beanName)) { String nameToLookup = originalBeanName(name); if (args != null) { return (T) parentBeanFactory.getBean(nameToLookup, args);;//父类容器，从父类容器获取bean。 } else { return parentBeanFactory.getBean(nameToLookup, requiredType);;//父类容器，从父类容器获取bean。 } } try { final RootBeanDefinition mbd = getMergedLocalBeanDefinition(beanName);//父子合并 String[] dependsOn = mbd.getDependsOn();//依赖的bean，创建这个bean的时候先要创建哪些bean， if (dependsOn != null) { for (String dependsOnBean : dependsOn) { if (isDependent(beanName, dependsOnBean)) {//没有依赖关系 throw new BeanCreationException("Circular depends-on relationship between '" + beanName + "' and '" + dependsOnBean + "'"); } registerDependentBean(dependsOnBean, beanName);//增加依赖关系， getBean(dependsOnBean);//先实例化依赖的bean } } if (mbd.isSingleton()) {//单利 sharedInstance = getSingleton(beanName, new ObjectFactory<Object>() { @Override public Object getObject() throws BeansException { try { return createBean(beanName, mbd, args); } } }); bean = getObjectForBeanInstance(sharedInstance, name, beanName, mbd); } else if (mbd.isPrototype()) {//多利 // It's a prototype -> create a new instance. Object prototypeInstance = null; try { beforePrototypeCreation(beanName); prototypeInstance = createBean(beanName, mbd, args); } finally { afterPrototypeCreation(beanName); } bean = getObjectForBeanInstance(prototypeInstance, name, beanName, mbd); } else { String scopeName = mbd.getScope(); final Scope scope = this.scopes.get(scopeName); if (scope == null) { throw new IllegalStateException("No Scope registered for scope '" + scopeName + "'"); } try { Object scopedInstance = scope.get(beanName, new ObjectFactory<Object>() { @Override public Object getObject() throws BeansException { beforePrototypeCreation(beanName); try { return createBean(beanName, mbd, args); } finally { afterPrototypeCreation(beanName); } } }); bean = getObjectForBeanInstance(scopedInstance, name, beanName, mbd); } } } } if (requiredType != null && bean != null && !requiredType.isAssignableFrom(bean.getClass())) { try { return getTypeConverter().convertIfNecessary(bean, requiredType); } } return (T) bean; } 单利： sharedInstance = getSingleton(beanName, new ObjectFactory<Object>() { @Override public Object getObject() throws BeansException { try { return createBean(beanName, mbd, args); } } }); public Object getSingleton(String beanName, ObjectFactory<?> singletonFactory) { synchronized (this.singletonObjects) {//缓存 Object singletonObject = this.singletonObjects.get(beanName); if (singletonObject == null) { try { singletonObject = singletonFactory.getObject(); //createBean } addSingleton(beanName, singletonObject);//缓存 } return (singletonObject != NULL_OBJECT ? singletonObject : null); } } protected Object createBean(final String beanName, final RootBeanDefinition mbd, final Object[] args)throws BeanCreationException { resolveBeanClass(mbd, beanName); //bean的定义，bean的名字，拿出beanClass， try { mbd.prepareMethodOverrides(); } try { Object bean = resolveBeforeInstantiation(beanName, mbd);//BeanPostProcessors已经实例化了，实例化之前插一脚，直接返回这个实例化的bean。后面不用走了。可以自己去实例化这个bean，spring就不会管这个bean的实例化了。下面有梨子InstantiationAwareBeanPostProcessorTest， if (bean != null) { return bean; } } //前面resolveBeforeInstantiation没有成功实例化出这个bean。spring来实例化这个bean。 Object beanInstance = doCreateBean(beanName, mbd, args); return beanInstance; } protected Object resolveBeforeInstantiation(String beanName, RootBeanDefinition mbd) { Object bean = null; if (!Boolean.FALSE.equals(mbd.beforeInstantiationResolved)) { if (mbd.hasBeanClass() && !mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) { bean = applyBeanPostProcessorsBeforeInstantiation(mbd.getBeanClass(), beanName); if (bean != null) { bean = applyBeanPostProcessorsAfterInitialization(bean, beanName); //先执行before在执行after方法， } } mbd.beforeInstantiationResolved = (bean != null); } return bean; } protected Object applyBeanPostProcessorsBeforeInstantiation(Class<?> beanClass, String beanName)throws BeansException { for (BeanPostProcessor bp : getBeanPostProcessors()) { //取出所有的BeanPostProcessors， if (bp instanceof InstantiationAwareBeanPostProcessor) { // 实现InstantiationAwareBeanPostProcessor接口的自己写的类，可以自己去实例化这个bean，spring就不会管这个bean的实例化了。下面有梨子InstantiationAwareBeanPostProcessorTest， InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp; Object result = ibp.postProcessBeforeInstantiation(beanClass, beanName); //通过所有的BeanPostProcessors来返回这个实例化的bean。spring就不会管这个bean的实例化了。 if (result != null) { return result; } } } return null; } public class InstantiationAwareBeanPostProcessorTest implements InstantiationAwareBeanPostProcessor { @Override public Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) throws BeansException { try { return beanClass.newInstance(); } catch (InstantiationException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } return null; } protected Object doCreateBean(final String beanName, final RootBeanDefinition mbd, final Object[] args) { BeanWrapper instanceWrapper = null; if (mbd.isSingleton()) { instanceWrapper = this.factoryBeanInstanceCache.remove(beanName);//缓存， } if (instanceWrapper == null) { instanceWrapper = createBeanInstance(beanName, mbd, args); // 包装类，通过反射实例创建完成。但是实例的属性还没有操作。不包括IOC的依赖注入。属性是没有值的。 } final Object bean = (instanceWrapper != null ? instanceWrapper.getWrappedInstance() : null); Class<?> beanType = (instanceWrapper != null ? instanceWrapper.getWrappedClass() : null); synchronized (mbd.postProcessingLock) { if (!mbd.postProcessed) { applyMergedBeanDefinitionPostProcessors(mbd, beanType, beanName); //下面解析，
//解析完这个类需要依赖注入的字段和方法之后，在AutowiredAnnotationBeanPostProcessor增加一行记录factoryBeanTest=[FactoryBeanTest.woman（依赖注入字段）, FactoryBeanTest.setWoman(com.zhuguang.jack.testbean.Woman)（依赖注入方法）]。 } mbd.postProcessed = true; } } boolean earlySingletonExposure = (mbd.isSingleton() && this.allowCircularReferences && isSingletonCurrentlyInCreation(beanName)); // 是单利并且允许循环依赖， if (earlySingletonExposure) { addSingletonFactory(beanName, new ObjectFactory<Object>() {//把ObjectFactory这个匿名对象加入到spring的三级缓存，在getSingleton从缓存取的时候，会调用三级缓存中的匿名对象ObjectFactory的getObject() 。 @Override public Object getObject() throws BeansException { return getEarlyBeanReference(beanName, mbd, bean); } }); } Object exposedObject = bean; try { populateBean(beanName, mbd, instanceWrapper); //IOC，依赖注入8中类型， if (exposedObject != null) { exposedObject = initializeBean(beanName, exposedObject, mbd); } } if (earlySingletonExposure) { Object earlySingletonReference = getSingleton(beanName, false); if (earlySingletonReference != null) { if (exposedObject == bean) { exposedObject = earlySingletonReference; } else if (!this.allowRawInjectionDespiteWrapping && hasDependentBean(beanName)) { String[] dependentBeans = getDependentBeans(beanName); Set<String> actualDependentBeans = new LinkedHashSet<String>(dependentBeans.length); for (String dependentBean : dependentBeans) { if (!removeSingletonIfCreatedForTypeCheckOnly(dependentBean)) { actualDependentBeans.add(dependentBean); } } if (!actualDependentBeans.isEmpty()) { throw new BeanCurrentlyInCreationException(beanName,"); } } } } try { registerDisposableBeanIfNecessary(beanName, bean, mbd); //注册， } return exposedObject; } protected BeanWrapper createBeanInstance(String beanName, RootBeanDefinition mbd, Object[] args) { Class<?> beanClass = resolveBeanClass(mbd, beanName);//拿到bean的class，class com.zhuguang.jack.testbean.A， if (mbd.getFactoryMethodName() != null) { return instantiateUsingFactoryMethod(beanName, mbd, args); //自己写的类去初始化，不要spring实例化， } return instantiateBean(beanName, mbd); } protected BeanWrapper instantiateBean(final String beanName, final RootBeanDefinition mbd) { try { Object beanInstance; final BeanFactory parent = this; if (System.getSecurityManager() != null) { //代码执行权限， beanInstance = AccessController.doPrivileged(new PrivilegedAction<Object>() { @Override public Object run() { return getInstantiationStrategy().instantiate(mbd, beanName, parent); } }, getAccessControlContext()); } else { beanInstance = getInstantiationStrategy().instantiate(mbd, beanName, parent); //通过反射，com.zhuguang.jack.testbean.A@5226e402实例创建完成。 } BeanWrapper bw = new BeanWrapperImpl(beanInstance); //包装， initBeanWrapper(bw); return bw; } } public Object instantiate(RootBeanDefinition beanDefinition, String beanName, BeanFactory owner) { if (beanDefinition.getMethodOverrides().isEmpty()) { synchronized (beanDefinition.constructorArgumentLock) { constructorToUse = (Constructor<?>) beanDefinition.resolvedConstructorOrFactoryMethod; if (constructorToUse == null) { final Class<?> clazz = beanDefinition.getBeanClass(); //拿到需要实例化的类， try { if (System.getSecurityManager() != null) { constructorToUse = AccessController.doPrivileged(new PrivilegedExceptionAction<Constructor<?>>() { @Override public Constructor<?> run() throws Exception { return clazz.getDeclaredConstructor((Class[]) null); //拿到构造器，无参构造器，为了防止循环依赖问题。 } }); } } } } return BeanUtils.instantiateClass(constructorToUse);//反射，实例化bean， } else { return instantiateWithMethodInjection(beanDefinition, beanName, owner);//Cglib } } protected void applyMergedBeanDefinitionPostProcessors(RootBeanDefinition mbd, Class<?> beanType, String beanName)throws BeansException { try { for (BeanPostProcessor bp : getBeanPostProcessors()) { if (bp instanceof MergedBeanDefinitionPostProcessor) {//实现这个接口的bean，才能做处理， MergedBeanDefinitionPostProcessor bdp = (MergedBeanDefinitionPostProcessor) bp; // 有一个AutowiredAnnotationBeanPostProcessor， bdp.postProcessMergedBeanDefinition(mbd, beanType, beanName); } } } } AutowiredAnnotationBeanPostProcessor类的：依赖注入可以通过配置文件，也可以通过注解@Autowired，@Autowired，可以加载属性上面，也可以加载set方法上面。 public void postProcessMergedBeanDefinition(RootBeanDefinition beanDefinition, Class<?> beanType, String beanName) { if (beanType != null) { InjectionMetadata metadata = findAutowiringMetadata(beanName, beanType); //返回这个类，需要注解依赖注入的属性和方法， metadata.checkConfigMembers(beanDefinition); } } private InjectionMetadata findAutowiringMetadata(String beanName, Class<?> clazz) { String cacheKey = (StringUtils.hasLength(beanName) ? beanName : clazz.getName()); InjectionMetadata metadata = this.injectionMetadataCache.get(cacheKey); //AutowiredAnnotationBeanPostProcessor的缓存， if (InjectionMetadata.needsRefresh(metadata, clazz)) { synchronized (this.injectionMetadataCache) { metadata = this.injectionMetadataCache.get(cacheKey); if (InjectionMetadata.needsRefresh(metadata, clazz)) { metadata = buildAutowiringMetadata(clazz); //返回这个类，需要注解依赖注入的属性和方法， this.injectionMetadataCache.put(cacheKey, metadata); //解析完这个类需要依赖注入的字段和方法之后，在AutowiredAnnotationBeanPostProcessor增加一行记录factoryBeanTest = [ FactoryBeanTest.woman, FactoryBeanTest.setWoman(com.zhuguang.jack.testbean.Woman)]，this=AutowiredAnnotationBeanPostProcessor。 } } } return metadata; } private InjectionMetadata buildAutowiringMetadata(Class<?> clazz) { LinkedList<InjectionMetadata.InjectedElement> elements = new LinkedList<InjectionMetadata.InjectedElement>(); Class<?> targetClass = clazz; do { LinkedList<InjectionMetadata.InjectedElement> currElements = new LinkedList<InjectionMetadata.InjectedElement>(); //InjectedElement是反射的属性或者方法对象， //@Autowired加载属性上面， for (Field field : targetClass.getDeclaredFields()) { // 拿到类的所有属性， AnnotationAttributes annotation = findAutowiredAnnotation(field); //获取字段的Autowired，Value，Inject 3种注解，其余注解不管，返回映射关系， if (annotation != null) { if (Modifier.isStatic(field.getModifiers())) { continue; } boolean required = determineRequiredStatus(annotation);//拿到注解的值， currElements.add(new AutowiredFieldElement(field, required)); //一个字段field对应一个AutowiredFieldElement，装到容器中。还没有涉及到IOC过程。 } } //@Autowired加载set方法上面， for (Method method : targetClass.getDeclaredMethods()) { // 拿到类的所有方法，有注解的方法是 FactoryBeanTest.setWoman(com.zhuguang.jack.testbean.Woman)。 @Autowired public void setWoman(Woman woman) { this.woman = woman; }， Method bridgedMethod = BridgeMethodResolver.findBridgedMethod(method); //方法的重载 AnnotationAttributes annotation = BridgeMethodResolver.isVisibilityBridgeMethodPair(method, bridgedMethod) ? findAutowiredAnnotation(bridgedMethod) : findAutowiredAnnotation(method); //找到这个方法上面有没有Autowired，Value，Inject 3种注解，其余注解不管， if (annotation != null && method.equals(ClassUtils.getMostSpecificMethod(method, clazz))) { if (Modifier.isStatic(method.getModifiers())) { continue; } boolean required = determineRequiredStatus(annotation);//拿到注解的值， PropertyDescriptor pd = BeanUtils.findPropertyForMethod(method);//拿到方法的类型对象PropertyDescriptor currElements.add(new AutowiredMethodElement(method, required, pd));//把method, required, pd包装成AutowiredMethodElement放到容器currElements中去， } } elements.addAll(0, currElements); targetClass = targetClass.getSuperclass(); } while (targetClass != null && targetClass != Object.class); //父类，也去解析父类， return new InjectionMetadata(clazz, elements); //返回这个类，需要注解依赖注入的属性和方法， } public AutowiredAnnotationBeanPostProcessor() { //AutowiredAnnotationBeanPostProcessor里面加了Autowired，Value，Inject 3种注解， this.autowiredAnnotationTypes.add(Autowired.class); this.autowiredAnnotationTypes.add(Value.class); ClassLoader cl = AutowiredAnnotationBeanPostProcessor.class.getClassLoader(); this.autowiredAnnotationTypes.add((Class<? extends Annotation>) cl.loadClass("javax.inject.Inject")); } singletonObjects是一级缓存，一个bean依赖注入完成之后，属性都完成了，才会存在在singletonObjects这个Map里面。 earlySingletonObjects是二级缓存，一个bean还没有完全实例化，有可能里面还有一些属性，还没有完全依赖注入完。 singletonFactories是三级缓存，里面存的是ObjectFactory对象。 二级三级缓存，就是为了解决循环依赖问题，A里面有B，B里面有A。A实例化的时候B没有实例化，此时A还是一个空壳子，会加到三级缓存，然后getBean(B)，B实例化的时候发现有属性A，会去实例化getBean(A)，此时A在三级缓存中，会调用这个三级缓存的getObject()方法。 protected Object getSingleton(String beanName, boolean allowEarlyReference) { Object singletonObject = this.singletonObjects.get(beanName);//从第一级取 if (singletonObject == null && isSingletonCurrentlyInCreation(beanName)) { synchronized (this.singletonObjects) { singletonObject = this.earlySingletonObjects.get(beanName);//从第二级取 if (singletonObject == null && allowEarlyReference) { ObjectFactory<?> singletonFactory = this.singletonFactories.get(beanName);//从第三级取 if (singletonFactory != null) { singletonObject = singletonFactory.getObject(); //三级缓存调用getObject()， this.earlySingletonObjects.put(beanName, singletonObject);//移到二级缓存， this.singletonFactories.remove(beanName);//从三级缓存删除， } } } } return (singletonObject != NULL_OBJECT ? singletonObject : null); } protected void addSingletonFactory(String beanName, ObjectFactory<?> singletonFactory) { synchronized (this.singletonObjects) { if (!this.singletonObjects.containsKey(beanName)) {//一级缓存没有 this.singletonFactories.put(beanName, singletonFactory);//放入三级缓存，准备上面的，调用三级缓存的getObject()， this.earlySingletonObjects.remove(beanName);//二级缓存移除 this.registeredSingletons.add(beanName); } } } protected Object getEarlyBeanReference(String beanName, RootBeanDefinition mbd, Object bean) { Object exposedObject = bean; if (bean != null && !mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) { for (BeanPostProcessor bp : getBeanPostProcessors()) { if (bp instanceof SmartInstantiationAwareBeanPostProcessor) { //这个接口， SmartInstantiationAwareBeanPostProcessor ibp = (SmartInstantiationAwareBeanPostProcessor) bp; exposedObject = ibp.getEarlyBeanReference(exposedObject, beanName); if (exposedObject == null) { return exposedObject; } } } } return exposedObject; } protected void populateBean(String beanName, RootBeanDefinition mbd, BeanWrapper bw) { PropertyValues pvs = mbd.getPropertyValues(); //拿到factoryBeanTest的需要依赖注入的属性，PropertyValues: length=1; bean property 'woman' boolean continueWithPropertyPopulation = true; //当前bean的依赖注入到底要不要做， if (!mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) { for (BeanPostProcessor bp : getBeanPostProcessors()) { if (bp instanceof InstantiationAwareBeanPostProcessor) { // InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp; if (!ibp.postProcessAfterInstantiation(bw.getWrappedInstance(), beanName)) { //返回布尔值，当前bean的依赖注入要不要做， continueWithPropertyPopulation = false; break; } } } } if (!continueWithPropertyPopulation) { //为false，当前bean的依赖注入就不用做了， return; } boolean hasInstAwareBpps = hasInstantiationAwareBeanPostProcessors(); //有没有实现InstantiationAwareBeanPostProcessor接口， boolean needsDepCheck = (mbd.getDependencyCheck() != RootBeanDefinition.DEPENDENCY_CHECK_NONE); if (hasInstAwareBpps || needsDepCheck) { PropertyDescriptor[] filteredPds = filterPropertyDescriptorsForDependencyCheck(bw, mbd.allowCaching); if (hasInstAwareBpps) { for (BeanPostProcessor bp : getBeanPostProcessors()) { if (bp instanceof InstantiationAwareBeanPostProcessor) { //找到这个接口的类，包括spring的和自己的， InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp; pvs = ibp.postProcessPropertyValues(pvs, filteredPds, bw.getWrappedInstance(), beanName);//@Autoware,@Value的依赖注入。 AutowiredAnnotationBeanPostProcessor类的postProcessPropertyValues方法，依赖注入在这里。 if (pvs == null) { return; } } } } } applyPropertyValues(beanName, mbd, bw, pvs); //通过xml依赖注入， } AutowiredAnnotationBeanPostProcessor类： public PropertyValues postProcessPropertyValues(PropertyValues pvs, PropertyDescriptor[] pds, Object bean, String beanName) throws BeansException { InjectionMetadata metadata = findResourceMetadata(beanName, bean.getClass()); //从缓存取，需要依赖注入的字段和方法，[FactoryBeanTest.woman, .FactoryBeanTest.setWoman(com.zhuguang.jack.testbean.Woman)]， try { metadata.inject(bean, beanName, pvs);//依赖注入在这里。 } return pvs; } public void inject(Object target, String beanName, PropertyValues pvs) throws Throwable { Collection<InjectedElement> elementsToIterate = (this.checkedElements != null ? this.checkedElements : this.injectedElements); //[FactoryBeanTest.woman, FactoryBeanTest.setWoman(com.zhuguang.jack.testbean.Woman)]， if (!elementsToIterate.isEmpty()) { for (InjectedElement element : elementsToIterate) { element.inject(target, beanName, pvs); //目标对象FactoryBeanTest@5d39f2d8，bean名字factoryBeanTest，需要依赖注入的字段或者方法[bean property 'woman'] 。依赖注入在这里。 } } } //依赖注入字段。依赖注入在这里。 protected void inject(Object bean, String beanName, PropertyValues pvs) throws Throwable { Field field = (Field) this.member; //FactoryBeanTest.woman try { Object value; if (this.cached) { value = resolvedCachedArgument(beanName, this.cachedFieldValue); } else { DependencyDescriptor desc = new DependencyDescriptor(field, this.required); desc.setContainingClass(bean.getClass()); Set<String> autowiredBeanNames = new LinkedHashSet<String>(1); TypeConverter typeConverter = beanFactory.getTypeConverter(); value = beanFactory.resolveDependency(desc, beanName, autowiredBeanNames, typeConverter);//拿到依赖注入的属性的值，com.zhuguang.jack.testbean.Woman@abbc908。 synchronized (this) { if (!this.cached) { if (value != null || this.required) { this.cachedFieldValue = desc; registerDependentBeans(beanName, autowiredBeanNames); } this.cached = true; } } } if (value != null) {//com.zhuguang.jack.testbean.Woman@abbc908， ReflectionUtils.makeAccessible(field); field.set(bean, value); //字段设置值 } } } } public Object resolveDependency(DependencyDescriptor descriptor, String beanName, Set<String> autowiredBeanNames, TypeConverter typeConverter) throws BeansException { else { if (result == null) { result = doResolveDependency(descriptor, beanName, autowiredBeanNames, typeConverter); } return result;//com.zhuguang.jack.testbean.Woman@abbc908。 } } public Object doResolveDependency(DependencyDescriptor descriptor, String beanName, Set<String> autowiredBeanNames, TypeConverter typeConverter) throws BeansException { Class<?> type = descriptor.getDependencyType(); //class com.zhuguang.jack.testbean.Woman Object value = getAutowireCandidateResolver().getSuggestedValue(descriptor); if (value != null) { if (value instanceof String) { String strVal = resolveEmbeddedValue((String) value); BeanDefinition bd = (beanName != null && containsBean(beanName) ? getMergedBeanDefinition(beanName) : null); value = evaluateBeanDefinitionString(strVal, bd); } TypeConverter converter = (typeConverter != null ? typeConverter : getTypeConverter()); return (descriptor.getField() != null ? converter.convertIfNecessary(value, type, descriptor.getField()) : converter.convertIfNecessary(value, type, descriptor.getMethodParameter())); } if (type.isArray()) { //依赖注入的是数组 Class<?> componentType = type.getComponentType(); DependencyDescriptor targetDesc = new DependencyDescriptor(descriptor); targetDesc.increaseNestingLevel(); Map<String, Object> matchingBeans = findAutowireCandidates(beanName, componentType, targetDesc); if (matchingBeans.isEmpty()) { if (descriptor.isRequired()) { raiseNoSuchBeanDefinitionException(componentType, "array of " + componentType.getName(), descriptor); } return null; } if (autowiredBeanNames != null) { autowiredBeanNames.addAll(matchingBeans.keySet()); } TypeConverter converter = (typeConverter != null ? typeConverter : getTypeConverter()); Object result = converter.convertIfNecessary(matchingBeans.values(), type); if (this.dependencyComparator != null && result instanceof Object[]) { Arrays.sort((Object[]) result, this.dependencyComparator); } return result; } else if (Collection.class.isAssignableFrom(type) && type.isInterface()) { //依赖注入的是集合 Class<?> elementType = descriptor.getCollectionType(); if (elementType == null) { if (descriptor.isRequired()) { throw new FatalBeanException("No element type declared for collection [" + type.getName() + "]"); } return null; } DependencyDescriptor targetDesc = new DependencyDescriptor(descriptor); targetDesc.increaseNestingLevel(); Map<String, Object> matchingBeans = findAutowireCandidates(beanName, elementType, targetDesc); if (matchingBeans.isEmpty()) { if (descriptor.isRequired()) { raiseNoSuchBeanDefinitionException(elementType, "collection of " + elementType.getName(), descriptor); } return null; } if (autowiredBeanNames != null) { autowiredBeanNames.addAll(matchingBeans.keySet()); } TypeConverter converter = (typeConverter != null ? typeConverter : getTypeConverter()); Object result = converter.convertIfNecessary(matchingBeans.values(), type); if (this.dependencyComparator != null && result instanceof List) { Collections.sort((List<?>) result, this.dependencyComparator); } return result; } else if (Map.class.isAssignableFrom(type) && type.isInterface()) { //依赖注入的是MAp Class<?> keyType = descriptor.getMapKeyType(); if (keyType == null || !String.class.isAssignableFrom(keyType)) { if (descriptor.isRequired()) { throw new FatalBeanException("Key type [" + keyType + "] of map [" + type.getName() + "] must be assignable to [java.lang.String]"); } return null; } Class<?> valueType = descriptor.getMapValueType(); if (valueType == null) { if (descriptor.isRequired()) { throw new FatalBeanException("No value type declared for map [" + type.getName() + "]"); } return null; } DependencyDescriptor targetDesc = new DependencyDescriptor(descriptor); targetDesc.increaseNestingLevel(); Map<String, Object> matchingBeans = findAutowireCandidates(beanName, valueType, targetDesc); if (matchingBeans.isEmpty()) { if (descriptor.isRequired()) { raiseNoSuchBeanDefinitionException(valueType, "map with value type " + valueType.getName(), descriptor); } return null; } if (autowiredBeanNames != null) { autowiredBeanNames.addAll(matchingBeans.keySet()); } return matchingBeans; } else { //依赖注入不是数组，不是Map，不是集合，是基本类型或者对象， Map<String, Object> matchingBeans = findAutowireCandidates(beanName, type, descriptor); //{woman=com.zhuguang.jack.testbean.Woman@9a7a808}，从bean工厂获取，最终还是通过getBean()方法获取。 if (matchingBeans.size() > 1) {//依赖注入的类有多个，报错。 String primaryBeanName = determinePrimaryCandidate(matchingBeans, descriptor); if (primaryBeanName == null) { throw new NoUniqueBeanDefinitionException(type, matchingBeans.keySet()); } if (autowiredBeanNames != null) { autowiredBeanNames.add(primaryBeanName); } return matchingBeans.get(primaryBeanName); } Map.Entry<String, Object> entry = matchingBeans.entrySet().iterator().next(); if (autowiredBeanNames != null) { autowiredBeanNames.add(entry.getKey()); } return entry.getValue();//woman=com.zhuguang.jack.testbean.Woman@abbc908 } } protected Map<String, Object> findAutowireCandidates( String beanName, Class<?> requiredType, DependencyDescriptor descriptor) { for (String candidateName : candidateNames) { if (!candidateName.equals(beanName) && isAutowireCandidate(candidateName, descriptor)) { result.put(candidateName, getBean(candidateName)); //还是通过getBean()方法获取需要依赖注入的属性的值， } } return result; } //方法的依赖注入，依赖注入在这里。通过反射给方法设置值，形参通过getBean（）方法获取。 protected void inject(Object bean, String beanName, PropertyValues pvs) throws Throwable { else { Object arg = beanFactory.resolveDependency(desc, beanName, autowiredBeanNames, typeConverter); if (arg == null && !this.required) { arguments = null; break; } arguments[i] = arg; } } if (arguments != null) { ReflectionUtils.makeAccessible(method); method.invoke(bean, arguments); //通过反射给方法设置值，形参通过getBean（）方法获取。 } } } 上main是通过注解的依赖注入，还有通过XML的依赖注入。 protected void applyPropertyValues(String beanName, BeanDefinition mbd, BeanWrapper bw, PropertyValues pvs) { //通过xml依赖注入， MutablePropertyValues mpvs = null; List<PropertyValue> original; if (System.getSecurityManager() != null) { if (bw instanceof BeanWrapperImpl) { ((BeanWrapperImpl) bw).setSecurityContext(getAccessControlContext()); } } if (pvs instanceof MutablePropertyValues) { mpvs = (MutablePropertyValues) pvs; if (mpvs.isConverted()) { try { bw.setPropertyValues(mpvs); return; } } original = mpvs.getPropertyValueList(); //[bean property 'woman']，需要xml依赖注入的属性， } else { original = Arrays.asList(pvs.getPropertyValues()); //[bean property 'woman']，需要xml依赖注入的属性， } TypeConverter converter = getCustomTypeConverter(); if (converter == null) { converter = bw; } BeanDefinitionValueResolver valueResolver = new BeanDefinitionValueResolver(this, beanName, mbd, converter); List<PropertyValue> deepCopy = new ArrayList<PropertyValue>(original.size()); boolean resolveNecessary = false; for (PropertyValue pv : original) { else { String propertyName = pv.getName();//woman， Object originalValue = pv.getValue();//<woman>，RuntimeBeanReference类型， Object resolvedValue = valueResolver.resolveValueIfNecessary(pv, originalValue); //beanFactory.getBean(refName);从bean工厂拿。因为依赖注入的属性有可能是一个引用，有可能是一个字符串需要转换成时间， Object convertedValue = resolvedValue; //com.zhuguang.jack.testbean.Woman@9a7a808， boolean convertible = bw.isWritableProperty(propertyName) &&!PropertyAccessorUtils.isNestedOrIndexedProperty(propertyName); if (convertible) { convertedValue = convertForProperty(resolvedValue, propertyName, bw, converter);//com.zhuguang.jack.testbean.Woman@9a7a808，类型转换之后的值。上面的valueResolver.resolveValueIfNecessary(pv, originalValue)有可能转换还不够，还需要转换， } if (resolvedValue == originalValue) { if (convertible) { pv.setConvertedValue(convertedValue); } deepCopy.add(pv); } else if (convertible && originalValue instanceof TypedStringValue && !((TypedStringValue) originalValue).isDynamic() && !(convertedValue instanceof Collection || ObjectUtils.isArray(convertedValue))) { pv.setConvertedValue(convertedValue); deepCopy.add(pv); } else { resolveNecessary = true; deepCopy.add(new PropertyValue(pv, convertedValue)); //pv, convertedValue一个是原始属性值，一个是转换之后的值。封装成PropertyValue， } } } try { bw.setPropertyValues(new MutablePropertyValues(deepCopy)); //设置值，MutablePropertyValues才是需要真正设置的值。 } } public void setPropertyValue(PropertyValue pv) throws BeansException { PropertyTokenHolder tokens = (PropertyTokenHolder) pv.resolvedTokens; if (tokens == null) { String propertyName = pv.getName(); BeanWrapperImpl nestedBw; try { nestedBw = getBeanWrapperForPropertyPath(propertyName); } tokens = getPropertyNameTokens(getFinalPath(nestedBw, propertyName)); if (nestedBw == this) { pv.getOriginalPropertyValue().resolvedTokens = tokens; } nestedBw.setPropertyValue(tokens, pv); } else { setPropertyValue(tokens, pv); } } protected Object initializeBean(final String beanName, final Object bean, RootBeanDefinition mbd) { else { invokeAwareMethods(beanName, bean); } Object wrappedBean = bean; if (mbd == null || !mbd.isSynthetic()) { wrappedBean = applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName); } try { invokeInitMethods(beanName, wrappedBean, mbd); } if (mbd == null || !mbd.isSynthetic()) { wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName); } return wrappedBean; } public Object applyBeanPostProcessorsBeforeInitialization(Object existingBean, String beanName) throws BeansException { Object result = existingBean; for (BeanPostProcessor beanProcessor : getBeanPostProcessors()) { result = beanProcessor.postProcessBeforeInitialization(result, beanName); if (result == null) { return result; } } return result; } private void invokeAwareMethods(final String beanName, final Object bean) { if (bean instanceof Aware) { if (bean instanceof BeanNameAware) { ((BeanNameAware) bean).setBeanName(beanName); } if (bean instanceof BeanClassLoaderAware) { ((BeanClassLoaderAware) bean).setBeanClassLoader(getBeanClassLoader()); } if (bean instanceof BeanFactoryAware) { ((BeanFactoryAware) bean).setBeanFactory(AbstractAutowireCapableBeanFactory.this); } } } protected void invokeInitMethods(String beanName, final Object bean, RootBeanDefinition mbd)throws Throwable { boolean isInitializingBean = (bean instanceof InitializingBean); if (isInitializingBean && (mbd == null || !mbd.isExternallyManagedInitMethod("afterPropertiesSet"))) { else { ((InitializingBean) bean).afterPropertiesSet(); //实例化bean的时候，调用afterPropertiesSet()方法，没有参数，做资源的加载（redis，mongodb的加载，），一个bean只会调用一次。在bean实例化之后，IOC之后调用。 } } if (mbd != null) { String initMethodName = mbd.getInitMethodName(); if (initMethodName != null && !(isInitializingBean && "afterPropertiesSet".equals(initMethodName)) && !mbd.isExternallyManagedInitMethod(initMethodName)) { invokeCustomInitMethod(beanName, bean, mbd); } } } protected void invokeCustomInitMethod(String beanName, final Object bean, RootBeanDefinition mbd) throws Throwable { String initMethodName = mbd.getInitMethodName(); //拿到init方法的名称，init-method， final Method initMethod = (mbd.isNonPublicAccessAllowed() ? BeanUtils.findMethod(bean.getClass(), initMethodName) : ClassUtils.getMethodIfAvailable(bean.getClass(), initMethodName)); //反射得到这个方法， else { try { ReflectionUtils.makeAccessible(initMethod); initMethod.invoke(bean); //调用， } } } protected void registerDisposableBeanIfNecessary(String beanName, Object bean, RootBeanDefinition mbd) { AccessControlContext acc = (System.getSecurityManager() != null ? getAccessControlContext() : null); if (!mbd.isPrototype() && requiresDestruction(bean, mbd)) { if (mbd.isSingleton()) { //单利，就缓存， registerDisposableBean(beanName, new DisposableBeanAdapter(bean, beanName, mbd, getBeanPostProcessors(), acc)); } else { Scope scope = this.scopes.get(mbd.getScope()); if (scope == null) { throw new IllegalStateException("No Scope registered for scope '" + mbd.getScope() + "'"); } scope.registerDestructionCallback(beanName, new DisposableBeanAdapter(bean, beanName, mbd, getBeanPostProcessors(), acc)); } } } public void registerDisposableBean(String beanName, DisposableBean bean) { synchronized (this.disposableBeans) { this.disposableBeans.put(beanName, bean); } }