AbstractAutowireCapableBeanFactory继承于AbstractBeanFactory，主要负责bean创建后的相关处理，包括属性、装配、初始化等等。
类作用
AbstractAutowireCapableBeanFactory提供bean创建（构造函数带参）、属性填充、连接（包括自动连接）和初始化。处理运行时bean引用、解析托管集合、调用初始化方法等。支持自动连接构造函数、按名称的属性和按类型的属性。
类实现
createBean
实际创建bean的入口，通过重载适应多种情况，主体在Object createBean(String beanName, RootBeanDefinition mbd, @Nullable Object[] args)
/* 按类型创建bean，用于SCOPE_PROTOTYPE */
@Override
@SuppressWarnings("unchecked")
public <T> T createBean(Class<T> beanClass) throws BeansException {
// Use non-singleton bean definition, to avoid registering bean as dependent bean.
RootBeanDefinition bd = new CreateFromClassBeanDefinition(beanClass);
bd.setScope(SCOPE_PROTOTYPE);
bd.allowCaching = ClassUtils.isCacheSafe(beanClass, getBeanClassLoader());
return (T) createBean(beanClass.getName(), bd, null);
}
/* 自动装配模式下创建bean */
@Override
public Object createBean(Class<?> beanClass, int autowireMode, boolean dependencyCheck) throws BeansException {
// Use non-singleton bean definition, to avoid registering bean as dependent bean.
RootBeanDefinition bd = new RootBeanDefinition(beanClass, autowireMode, dependencyCheck);
bd.setScope(SCOPE_PROTOTYPE);
return createBean(beanClass.getName(), bd, null);
}
核心方法-createBean(String beanName, RootBeanDefinition mbd, @Nullable Object[] args)
实例化bean的主体实现：创建一个bean实例，填充bean实例，应用后处理器等
@Override
protected Object createBean(String beanName, RootBeanDefinition mbd, @Nullable Object[] args)
throws BeanCreationException {
if (logger.isTraceEnabled()) {
logger.trace("Creating instance of bean '" + beanName + "'");
}
RootBeanDefinition mbdToUse = mbd;
/* 加载bean的类文件。如果传入mbd原来没有beanClass，则复制mbd到mbdToUse，并把获取的beanClass赋值给mbdToUse.beanClass(不改变mbd现状) 注1 */
// Make sure bean class is actually resolved at this point, and
// clone the bean definition in case of a dynamically resolved Class
// which cannot be stored in the shared merged bean definition.
Class<?> resolvedClass = resolveBeanClass(mbd, beanName);
if (resolvedClass != null && !mbd.hasBeanClass() && mbd.getBeanClassName() != null) {
mbdToUse = new RootBeanDefinition(mbd);
mbdToUse.setBeanClass(resolvedClass);
}
//检查该Override的方法bean是否全部都有实现
// Prepare method overrides.
try {
mbdToUse.prepareMethodOverrides();
}
catch (BeanDefinitionValidationException ex) {
throw new BeanDefinitionStoreException(mbdToUse.getResourceDescription(),
beanName, "Validation of method overrides failed", ex);
}
try {
/*如果有实现了InstantiationAwareBeanPostProcessor接口的bean，且在其中创建了要生成的bean，直接返回，且后续框架针对bean的初始化过程均不执行 */
// Give BeanPostProcessors a chance to return a proxy instead of the target bean instance.
Object bean = resolveBeforeInstantiation(beanName, mbdToUse);
if (bean != null) {
return bean;
}
}
catch (Throwable ex) {
throw new BeanCreationException(mbdToUse.getResourceDescription(), beanName,
"BeanPostProcessor before instantiation of bean failed", ex);
}
try {
//spring实例化bean
Object beanInstance = doCreateBean(beanName, mbdToUse, args);
if (logger.isTraceEnabled()) {
logger.trace("Finished creating instance of bean '" + beanName + "'");
}
return beanInstance;
}
catch (BeanCreationException | ImplicitlyAppearedSingletonException ex) {
// A previously detected exception with proper bean creation context already,
// or illegal singleton state to be communicated up to DefaultSingletonBeanRegistry.
throw ex;
}
catch (Throwable ex) {
throw new BeanCreationException(
mbdToUse.getResourceDescription(), beanName, "Unexpected exception during bean creation", ex);
}
}
注1：resolveBeanClass见AbstractBeanFactory实现https://blog.youkuaiyun.com/davidwkx/article/details/130963899
resolveBeforeInstantiation
如果应用实现接口BeanPostProcessor，且有对当前bean实例化有自己实现，返回实现的bean
protected Object resolveBeforeInstantiation(String beanName, RootBeanDefinition mbd) {
Object bean = null;
//？为啥不直接用：if (mbd.beforeInstantiationResolved)
if (!Boolean.FALSE.equals(mbd.beforeInstantiationResolved)) {
// Make sure bean class is actually resolved at this point.
if (!mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) {
//确定mbd定义bean同要beanName代表的bean是一致的
Class<?> targetType = determineTargetType(beanName, mbd);
if (targetType != null) {
//调用postProcessBeforeInstantiation生成bean
bean = applyBeanPostProcessorsBeforeInstantiation(targetType, beanName);
if (bean != null) {
//如果postProcessBeforeInstantiation没产生bean，调用postProcessAfterInstantiation生成bean
bean = applyBeanPostProcessorsAfterInitialization(bean, beanName);
}
}
}
mbd.beforeInstantiationResolved = (bean != null);
}
return bean;
}
doCreateBean
创建bean前的工作全部完成，本方法实际创建一个指定的bean。
protected Object doCreateBean(String beanName, RootBeanDefinition mbd, @Nullable Object[] args)
throws BeanCreationException {
//bean封装器 注1
// Instantiate the bean.
BeanWrapper instanceWrapper = null;
if (mbd.isSingleton()) {
//单实例模式下，有可能该Bean创建之前就已经被创建出来了（比如在依赖注入过程中）。如果是这样，从bean实例工厂缓存删除
instanceWrapper = this.factoryBeanInstanceCache.remove(beanName);
}
if (instanceWrapper == null) {
//创建一个新的bean实例
instanceWrapper = createBeanInstance(beanName, mbd, args);
}
//取出bean对象
Object bean = instanceWrapper.getWrappedInstance();
//取beanType
Class<?> beanType = instanceWrapper.getWrappedClass();
if (beanType != NullBean.class) {
mbd.resolvedTargetType = beanType;
}
/* 用MergedBeanDefinitionPostProcessor（扩展点）修改设置属性 */
// Allow post-processors to modify the merged bean definition.
synchronized (mbd.postProcessingLock) {
if (!mbd.postProcessed) {
try {
applyMergedBeanDefinitionPostProcessors(mbd, beanType, beanName);
}
catch (Throwable ex) {
throw new BeanCreationException(mbd.getResourceDescription(), beanName,
"Post-processing of merged bean definition failed", ex);
}
//标记mbd.postProcessed已执行
mbd.markAsPostProcessed();
}
}
// 提前检测循环依赖：单例&允许循环依赖&当前bean正在创建中
// 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.isTraceEnabled()) {
logger.trace("Eagerly caching bean '" + beanName +
"' to allow for resolving potential circular references");
}
// 为避免后期循环依赖，可以在bean初始化完成前将创建实例的ObjectFactory加入工厂缓存池，从早期工厂缓存池删除
addSingletonFactory(beanName, () -> getEarlyBeanReference(beanName, mbd, bean));
}
//初始化bean实例(进行相关属性设置）
// Initialize the bean instance.
Object exposedObject = bean;
try {
// 对bean的属性进行填充，将各个属性值注入，其中，可能存在依赖于其他bean的属性，则会递归初始化依赖的bean
populateBean(beanName, mbd, instanceWrapper);
// 执行初始化逻辑: 应用工厂回调、init方法和bean后处理器
exposedObject = initializeBean(beanName, exposedObject, mbd);
}
catch (Throwable ex) {
if (ex instanceof BeanCreationException bce && beanName.equals(bce.getBeanName())) {
throw bce;
}
else {
throw new BeanCreationException(mbd.getResourceDescription(), beanName, ex.getMessage(), ex);
}
}
//处理循环依赖情况
if (earlySingletonExposure) {
//从缓存中获取bean对象
Object earlySingletonReference = getSingleton(beanName, false);
// earlySingletonReference只有在检测到有循环依赖的情况下才会不为空
if (earlySingletonReference != null) {
//初始化的bean-exposedObject 同从缓存中获得的bean是否相同
if (exposedObject == bean) {
exposedObject = earlySingletonReference;
}
else if (!this.allowRawInjectionDespiteWrapping && hasDependentBean(beanName)) {
String[] dependentBeans = getDependentBeans(beanName);
Set<String> actualDependentBeans = new LinkedHashSet<>(dependentBeans.length);
for (String dependentBean : dependentBeans) {
//如果对应bean名称的实例仅用于类型检查就删除它，否则就表示还用于其它目的
if (!removeSingletonIfCreatedForTypeCheckOnly(dependentBean)) {
//用于其它目的bean名称加入到actualDependentBeans
actualDependentBeans.add(dependentBean);
}
}
// 因为bean创建后所依赖的bean一定是已经创建的，actualDependentBeans不为空则表示当前bean创建后其依赖的bean却没有全部创建完，也就是说存在循环依赖
if (!actualDependentBeans.isEmpty()) {
throw new BeanCurrentlyInCreationException(beanName,
"Bean with name '" + beanName + "' has been injected into other beans [" +
StringUtils.collectionToCommaDelimitedString(actualDependentBeans) +
"] in its raw version as part of a circular reference, but has eventually been " +
"wrapped. This means that said other beans do not use the final version of the " +
"bean. This is often the result of over-eager type matching - consider using " +
"'getBeanNamesForType' with the 'allowEagerInit' flag turned off, for example.");
}
}
}
}
// 注册销毁bean列表，便于销毁对象
// Register bean as disposable.
try {
registerDisposableBeanIfNecessary(beanName, bean, mbd);
}
catch (BeanDefinitionValidationException ex) {
throw new BeanCreationException(
mbd.getResourceDescription(), beanName, "Invalid destruction signature", ex);
}
return exposedObject;
}
注1：BeanWrapper -bean的封装器，提供分析和操作标准JavaBeans的操作：能够获取和设置属性值（单独或批量）、获取属性描述符以及查询属性的可读性/可写性。
createBeanInstance
创建beand的一个新实例，创建方式有很多种，包括：生产者、工厂方法、构造函数自动装配或正常实例化等。
protected BeanWrapper createBeanInstance(String beanName, RootBeanDefinition mbd, @Nullable Object[] args) {
//确保beanClass已被加载
// Make sure bean class is actually resolved at this point.
Class<?> beanClass = resolveBeanClass(mbd, beanName);
if (beanClass != null && !Modifier.isPublic(beanClass.getModifiers()) && !mbd.isNonPublicAccessAllowed()) {
throw new BeanCreationException(mbd.getResourceDescription(), beanName,
"Bean class isn't public, and non-public access not allowed: " + beanClass.getName());
}
//如果bean是生产者（Supplier）提供的，则直接由生产者提供bean对象
Supplier<?> instanceSupplier = mbd.getInstanceSupplier();
if (instanceSupplier != null) {
return obtainFromSupplier(instanceSupplier, beanName, mbd);
}
//如果bean是工厂方法生成，例如：@Bean注解放在方法上/xml: factory-method，返回值注入容器，spring 会认为这是一个工厂方法 注1
if (mbd.getFactoryMethodName() != null) {
return instantiateUsingFactoryMethod(beanName, mbd, args);
}
/* spring会将解析过后确定下来的构造器或工厂方法缓存到mbd中resolvedConstructorOrFactoryMethod字段中。下次创建相同bean时直接从缓存的值获取，加快创建过程*/
// Shortcut when re-creating the same bean...
boolean resolved = false;
boolean autowireNecessary = false;
if (args == null) {
synchronized (mbd.constructorArgumentLock) {
if (mbd.resolvedConstructorOrFactoryMethod != null) {
resolved = true;
autowireNecessary = mbd.constructorArgumentsResolved;
}
}
}
if (resolved) {
if (autowireNecessary) {
//构造函数自动注入
return autowireConstructor(beanName, mbd, null, null);
}
else {
// 使用默认构造函数构造
return instantiateBean(beanName, mbd);
}
}
//用自动装配构建器创建bean： 从bean后置处理器中为自动装配寻找构造方法, 有且仅有一个有参构造或者有且仅有@Autowired注解构造
// Candidate constructors for autowiring?
Constructor<?>[] ctors = determineConstructorsFromBeanPostProcessors(beanClass, beanName);
// 以下情况符合其一即可进入
// 1、存在可选构造方法
// 2、构造函数为自动装配模式
// 3、BeanDefinition中有构造参数值
// 4、有构造函数参数列表的参数
if (ctors != null || mbd.getResolvedAutowireMode() == AUTOWIRE_CONSTRUCTOR ||
mbd.hasConstructorArgumentValues() || !ObjectUtils.isEmpty(args)) {
return autowireConstructor(beanName, mbd, ctors, args);
}
//用高优先级的构造器创建bean
// Preferred constructors for default construction?
ctors = mbd.getPreferredConstructors();
if (ctors != null) {
return autowireConstructor(beanName, mbd, ctors, null);
}
//默认使用无参构造器创建bean
// No special handling: simply use no-arg constructor.
return instantiateBean(beanName, mbd);
}
注1：instantiateUsingFactoryMethod实际实现在ConstructorResolver.instantiateUsingFactoryMethod，详见https://blog.youkuaiyun.com/davidwkx/article/details/131047724
populateBean
设置bean属性
protected void populateBean(String beanName, RootBeanDefinition mbd, @Nullable BeanWrapper bw) {
if (bw == null) {
if (mbd.hasPropertyValues()) {
throw new BeanCreationException(
mbd.getResourceDescription(), beanName, "Cannot apply property values to null instance");
}
else {
// Skip property population phase for null instance.
return;
}
}
//bean不是java.lang.Record类型
if (bw.getWrappedClass().isRecord()) {
if (mbd.hasPropertyValues()) {
throw new BeanCreationException(
mbd.getResourceDescription(), beanName, "Cannot apply property values to a record");
}
else {
// Skip property population phase for records since they are immutable.
return;
}
}
//属性设置前，如果有InstantiationAwareBeanPostProcessors实现，就按此处理，直接返回
// Give any InstantiationAwareBeanPostProcessors the opportunity to modify the
// state of the bean before properties are set. This can be used, for example,
// to support styles of field injection.
if (!mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) {
for (InstantiationAwareBeanPostProcessor bp : getBeanPostProcessorCache().instantiationAware) {
if (!bp.postProcessAfterInstantiation(bw.getWrappedInstance(), beanName)) {
return;
}
}
}
/* 获取bean属性集，对每个属性进行初始化 */
PropertyValues pvs = (mbd.hasPropertyValues() ? mbd.getPropertyValues() : null);
//属性设置方式
int resolvedAutowireMode = mbd.getResolvedAutowireMode();
if (resolvedAutowireMode == AUTOWIRE_BY_NAME || resolvedAutowireMode == AUTOWIRE_BY_TYPE) {
/*按名称或类型装配 */
MutablePropertyValues newPvs = new MutablePropertyValues(pvs);
// Add property values based on autowire by name if applicable.
if (resolvedAutowireMode == AUTOWIRE_BY_NAME) {
autowireByName(beanName, mbd, bw, newPvs);
}
// Add property values based on autowire by type if applicable.
if (resolvedAutowireMode == AUTOWIRE_BY_TYPE) {
autowireByType(beanName, mbd, bw, newPvs);
}
pvs = newPvs;
}
//属性设置后，如果有InstantiationAwareBeanPostProcessors实现，就执行
if (hasInstantiationAwareBeanPostProcessors()) {
if (pvs == null) {
pvs = mbd.getPropertyValues();
}
for (InstantiationAwareBeanPostProcessor bp : getBeanPostProcessorCache().instantiationAware) {
//调用postProcessProperties实现对属性设置
PropertyValues pvsToUse = bp.postProcessProperties(pvs, bw.getWrappedInstance(), beanName);
if (pvsToUse == null) {
return;
}
pvs = pvsToUse;
}
}
/*执行相关性检查，以确保已设置所有公开的属性。*/
boolean needsDepCheck = (mbd.getDependencyCheck() != AbstractBeanDefinition.DEPENDENCY_CHECK_NONE);
if (needsDepCheck) {
PropertyDescriptor[] filteredPds = filterPropertyDescriptorsForDependencyCheck(bw, mbd.allowCaching);
//依赖关系检查包括对象（协作bean）、简单类型（如字符串）
checkDependencies(beanName, mbd, filteredPds, pvs);
}
if (pvs != null) {
//把pvs中的属性值，采用深度复制，解析到运行期bean对其它bean引用。
applyPropertyValues(beanName, mbd, bw, pvs);
}
}
autowireByName/autowireByType
按名称或类型装配bean属性。
protected void autowireByName(
String beanName, AbstractBeanDefinition mbd, BeanWrapper bw, MutablePropertyValues pvs) {
//查找未处理的且非简单类型（指String等java基本类型）的属性
String[] propertyNames = unsatisfiedNonSimpleProperties(mbd, bw);
for (String propertyName : propertyNames) {
if (containsBean(propertyName)) {
//获取bean（来源于属性依赖关系进行的bean创建）
Object bean = getBean(propertyName);
//建立属性和bean关系
pvs.add(propertyName, bean);
//注册依赖关系
registerDependentBean(propertyName, beanName);
if (logger.isTraceEnabled()) {
logger.trace("Added autowiring by name from bean name '" + beanName +
"' via property '" + propertyName + "' to bean named '" + propertyName + "'");
}
}
else {
if (logger.isTraceEnabled()) {
logger.trace("Not autowiring property '" + propertyName + "' of bean '" + beanName +
"' by name: no matching bean found");
}
}
}
}
protected void autowireByType(
String beanName, AbstractBeanDefinition mbd, BeanWrapper bw, MutablePropertyValues pvs) {
//获取类型转换器
TypeConverter converter = getCustomTypeConverter();
if (converter == null) {
converter = bw;
}
Set<String> autowiredBeanNames = new LinkedHashSet<>(4);
//查找未处理的且非简单类型（指String等java基本类型）的属性
String[] propertyNames = unsatisfiedNonSimpleProperties(mbd, bw);
for (String propertyName : propertyNames) {
try {
//获取属性的PropertyDescriptor
PropertyDescriptor pd = bw.getPropertyDescriptor(propertyName);
// Don't try autowiring by type for type Object: never makes sense,
// even if it technically is an unsatisfied, non-simple property.
//属性是Object类型，而Obejct是java根类，无确定意义，无需装配
if (Object.class != pd.getPropertyType()) {
//获取属性相关的set方法
MethodParameter methodParam = BeanUtils.getWriteMethodParameter(pd);
// Do not allow eager init for type matching in case of a prioritized post-processor.
boolean eager = !(bw.getWrappedInstance() instanceof PriorityOrdered);
DependencyDescriptor desc = new AutowireByTypeDependencyDescriptor(methodParam, eager);
// 解析指定beanName对应的属性，并将解析到的属性名放入autowiredBeanNames，根据类型查找依赖关系 注1
Object autowiredArgument = resolveDependency(desc, beanName, autowiredBeanNames, converter);
if (autowiredArgument != null) {
pvs.add(propertyName, autowiredArgument);
}
for (String autowiredBeanName : autowiredBeanNames) {
registerDependentBean(autowiredBeanName, beanName);
if (logger.isTraceEnabled()) {
logger.trace("Autowiring by type from bean name '" + beanName + "' via property '" +
propertyName + "' to bean named '" + autowiredBeanName + "'");
}
}
autowiredBeanNames.clear();
}
}
catch (BeansException ex) {
throw new UnsatisfiedDependencyException(mbd.getResourceDescription(), beanName, propertyName, ex);
}
}
}
注1：resolveDependency 实现见子类DefaultListableBeanFactory.resolveDependency ，详见：https://blog.youkuaiyun.com/davidwkx/article/details/130715587
applyPropertyValues
把pvs中的属性值，采用深度复制，解析到运行期bean对其它bean引用。
protected void applyPropertyValues(String beanName, BeanDefinition mbd, BeanWrapper bw, PropertyValues pvs) {
if (pvs.isEmpty()) {
return;
}
MutablePropertyValues mpvs = null;
//记录原始属性值列表
List<PropertyValue> original;
//pvs是MutablePropertyValues 类型
if (pvs instanceof MutablePropertyValues _mpvs) {
mpvs = _mpvs;
if (mpvs.isConverted()) {
//mpvs只包含转换后的值
// Shortcut: use the pre-converted values as-is.
try {
//使用mpvs批量设置bw包装的Bean对象属性，然后直接结束
bw.setPropertyValues(mpvs);
return;
}
catch (BeansException ex) {
throw new BeanCreationException(
mbd.getResourceDescription(), beanName, "Error setting property values", ex);
}
}
//获取mpvs的PropertyValue对象列表
original = mpvs.getPropertyValueList();
}
else {
//获取pvs的PropertyValue对象列表
original = Arrays.asList(pvs.getPropertyValues());
}
////获取工厂的自定义类型转换器
TypeConverter converter = getCustomTypeConverter();
if (converter == null) {
//使用bw作为转换器
converter = bw;
}
//在bean工厂实现中使用Helper类-bean定义值解析器，它将beanDefinition对象中包含的值解析为应用于目标bean实例的实际值
BeanDefinitionValueResolver valueResolver = new BeanDefinitionValueResolver(this, beanName, mbd, converter);
//创建一个深拷贝，解析任何值引用
// Create a deep copy, resolving any references for values.
List<PropertyValue> deepCopy = new ArrayList<>(original.size());
boolean resolveNecessary = false;
for (PropertyValue pv : original) {
if (pv.isConverted()) {
//pv已转换值
deepCopy.add(pv);
}
else {
String propertyName = pv.getName();
Object originalValue = pv.getValue();
//如果originalValue 值是AutowiredPropertyMarker标记
if (originalValue == AutowiredPropertyMarker.INSTANCE) {
//基于propertyName获取在bw中的setter方法
Method writeMethod = bw.getPropertyDescriptor(propertyName).getWriteMethod();
if (writeMethod == null) {
throw new IllegalArgumentException("Autowire marker for property without write method: " + pv);
}
//将writerMethod封装到DependencyDescriptor对象
originalValue = new DependencyDescriptor(new MethodParameter(writeMethod, 0), true);
}
//由值解析器解析出originalValue所封装的对象
Object resolvedValue = valueResolver.resolveValueIfNecessary(pv, originalValue);
//默认转换后的值是刚解析出来的值
Object convertedValue = resolvedValue;
//可转换标记: bw可写 && prepertyName不是表示索引属性或嵌套属性
boolean convertible = bw.isWritableProperty(propertyName) &&
!PropertyAccessorUtils.isNestedOrIndexedProperty(propertyName);
if (convertible) {
//将resolvedValue按属性类型转换
convertedValue = convertForProperty(resolvedValue, propertyName, bw, converter);
}
// 可以将转换后的值存储合并后BeanDefinition中，以避免对每个创建的Bean实例进行重新转换
//如果resolvedValue与originalValue是同一个对象
// Possibly store converted value in merged bean definition,
// in order to avoid re-conversion for every created bean instance.
if (resolvedValue == originalValue) {
if (convertible) {
//将resolvedValue按属性类型转换
pv.setConvertedValue(convertedValue);
}
//将pv添加到deepCopy中
deepCopy.add(pv);
}
//TypedStringValue:类型字符串的Holder,这个holder将只存储字符串值和目标类型。实际得转换将由Bean工厂执行
//如果可转换 && originalValue是TypedStringValue的实例 && orginalValue不是标记为动态【即不是一个表达式】&&
// convertedValue不是Collection对象 或 数组
else if (convertible && originalValue instanceof TypedStringValue typedStringValue &&
!typedStringValue.isDynamic() &&
!(convertedValue instanceof Collection || ObjectUtils.isArray(convertedValue))) {
//将convertedValue设置到pv中
pv.setConvertedValue(convertedValue);
//将pv添加到deepCopy中
deepCopy.add(pv);
}
else {
resolveNecessary = true;
//根据pv,convertedValue构建PropertyValue对象，并添加到deepCopy中
deepCopy.add(new PropertyValue(pv, convertedValue));
}
}
}
if (mpvs != null && !resolveNecessary) {
//设置转换标记
mpvs.setConverted();
}
// Set our (possibly massaged) deep copy.
try {
//以deepCopy构造一个新的MutablePropertyValues对象，然后设置到bw中对应的属性
bw.setPropertyValues(new MutablePropertyValues(deepCopy));
}
catch (BeansException ex) {
throw new BeanCreationException(mbd.getResourceDescription(), beanName, ex.getMessage(), ex);
}
}
initializeBean
初始化给定的bean实例：应用工厂回调以及init方法和bean后处理器
protected Object initializeBean(String beanName, Object bean, @Nullable RootBeanDefinition mbd) {
//初始化第1步：调用实现Aware的bean，设置对应属性
invokeAwareMethods(beanName, bean);
Object wrappedBean = bean;
if (mbd == null || !mbd.isSynthetic()) {
//初始化第2步：如果有则调用BeanPostProcessorsBeforeInitialization
wrappedBean = applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName);
}
try {
//初始化第3步：调用实现接口InitializingBean或了自定义init方法的bean
invokeInitMethods(beanName, wrappedBean, mbd);
}
catch (Throwable ex) {
throw new BeanCreationException(
(mbd != null ? mbd.getResourceDescription() : null), beanName, ex.getMessage(), ex);
}
if (mbd == null || !mbd.isSynthetic()) {
//初始化第4步：如果有则调用BeanPostProcessorsBeforeInitialization
wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);
}
return wrappedBean;
}
invokeAwareMethods
初始化的第一步就是执行实现Aware接口的bean，此处只执行三类Aware Bean：BeanNameAware 、BeanClassLoaderAware 、BeanFactoryAware 。
private void invokeAwareMethods(String beanName, Object bean) {
if (bean instanceof Aware) {
// beanNameAware处理
if (bean instanceof BeanNameAware beanNameAware) {
beanNameAware.setBeanName(beanName);
}
// beanClassLoaderAware处理
if (bean instanceof BeanClassLoaderAware beanClassLoaderAware) {
ClassLoader bcl = getBeanClassLoader();
if (bcl != null) {
beanClassLoaderAware.setBeanClassLoader(bcl);
}
}
// beanFactoryAware处理
if (bean instanceof BeanFactoryAware beanFactoryAware) {
beanFactoryAware.setBeanFactory(AbstractAutowireCapableBeanFactory.this);
}
}
}
applyBeanPostProcessorsBeforeInitialization / applyBeanPostProcessorsAfterInitialization
如果有实现BeanPostProcessor接口，则执行postProcessBeforeInitialization或postProcessAfterInitialization。
public Object applyBeanPostProcessorsBeforeInitialization(Object existingBean, String beanName)
throws BeansException {
Object result = existingBean;
//逐一对每个BeanPostProcessor实现bean调用postProcessBeforeInitialization
for (BeanPostProcessor processor : getBeanPostProcessors()) {
//注意：上一个BeanPostProcessor bean的行结果Bean是执行下一个的参数Object
Object current = processor.postProcessBeforeInitialization(result, beanName);
if (current == null) {
return result;
}
result = current;
}
//返回结果是经过所有BeanPostProcessor Bean处理后的bean
return result;
}
@Override
public Object applyBeanPostProcessorsAfterInitialization(Object existingBean, String beanName)
throws BeansException {
Object result = existingBean;
//逐一对每个BeanPostProcessor实现bean调用postProcessAfterInitialization
for (BeanPostProcessor processor : getBeanPostProcessors()) {
//注意：上一个BeanPostProcessor bean的行结果Bean是执行下一个的参数Object
Object current = processor.postProcessAfterInitialization(result, beanName);
if (current == null) {
return result;
}
result = current;
}
//返回结果是经过所有BeanPostProcessor Bean处理后的bean
return result;
}
invokeInitMethods
执行初始化方法，包括bean实现InitializingBean接口afterPropertiesSet或配置了初始化方法。
protected void invokeInitMethods(String beanName, Object bean, @Nullable RootBeanDefinition mbd)
throws Throwable {
boolean isInitializingBean = (bean instanceof InitializingBean);
//实现了InitializingBean接口afterPropertiesSet，直接执行
if (isInitializingBean && (mbd == null || !mbd.hasAnyExternallyManagedInitMethod("afterPropertiesSet"))) {
if (logger.isTraceEnabled()) {
logger.trace("Invoking afterPropertiesSet() on bean with name '" + beanName + "'");
}
((InitializingBean) bean).afterPropertiesSet();
}
if (mbd != null && bean.getClass() != NullBean.class) {
String[] initMethodNames = mbd.getInitMethodNames();
//配置了初始化方法的bean(@PreConstruct或xml模式init-method)，直接执行
if (initMethodNames != null) {
for (String initMethodName : initMethodNames) {
if (StringUtils.hasLength(initMethodName) &&
//不是InitializingBean
!(isInitializingBean && "afterPropertiesSet".equals(initMethodName)) &&
//不是外部管理的init方法
!mbd.hasAnyExternallyManagedInitMethod(initMethodName)) {
//用反射机制执行初始化方法
invokeCustomInitMethod(beanName, bean, mbd, initMethodName);
}
}
}
}
}
invokeCustomInitMethod
用反射机制执行init方法
protected void invokeCustomInitMethod(String beanName, Object bean, RootBeanDefinition mbd, String initMethodName)
throws Throwable {
//取方法（方法存在且必须可访问）
Method initMethod = (mbd.isNonPublicAccessAllowed() ?
BeanUtils.findMethod(bean.getClass(), initMethodName) :
ClassUtils.getMethodIfAvailable(bean.getClass(), initMethodName));
//方法不存在
if (initMethod == null) {
if (mbd.isEnforceInitMethod()) {
throw new BeanDefinitionValidationException("Could not find an init method named '" +
initMethodName + "' on bean with name '" + beanName + "'");
}
else {
if (logger.isTraceEnabled()) {
logger.trace("No default init method named '" + initMethodName +
"' found on bean with name '" + beanName + "'");
}
// Ignore non-existent default lifecycle methods.
return;
}
}
if (logger.isTraceEnabled()) {
logger.trace("Invoking init method '" + initMethodName + "' on bean with name '" + beanName + "'");
}
//缓存initMethod，确定接口方法
Method methodToInvoke = ClassUtils.getInterfaceMethodIfPossible(initMethod, bean.getClass());
try {
//反射机制执行方法
ReflectionUtils.makeAccessible(methodToInvoke);
methodToInvoke.invoke(bean);
}
catch (InvocationTargetException ex) {
throw ex.getTargetException();
}
}
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