Spring IOC（6）AbstractAutowireCap
2020-12-13 本文已影响0人
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DefaultListableBeanFactory继承关系
继续从这张继承关系往下走，AbstractBeanFactory的子类AbstractAutowireCapableBeanFactory，它额外还实现了AutowireCapableBeanFactory。
上一章我们回顾了所遇到的BeanFactory的接口，AutowireCapableBeanFactory主要是用于自动装配，Bean的创建、属性填充、连接(包括自动装配)、初始化和销毁，以及BeanPostProcessor的调用。
AbstractAutowireCapableBeanFactory
AbstractAutowireCapableBeanFactory会对接口方法进行实现，比如createBean(), initializeBean(), applyBeanPostProcessorsBeforeInitialization(), applyBeanPostProcessorsAfterInitialization()。
此外上面提到对于属性的填充的方法在getBean的过程中也是高频率调用的，比如applyPropertyValues(beanName, BeanDefinition, BeanWrapper, PropertyValues)，以及resolveDependency(DependencyDescriptor, requestingBeanName)
public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFactory
implements AutowireCapableBeanFactory {
//策略模式，默认是Cglib，也可以是JDK动态代理
private InstantiationStrategy instantiationStrategy = new CglibSubclassingInstantiationStrategy();
//是否允许bean的循环引用，默认是true
private boolean allowCircularReferences = true;
//忽略给定type的自动装配功能autowiring
private final Set<Class<?>> ignoredDependencyTypes = new HashSet<>();
//忽略给定interface的自动装配功能autowiring
private final Set<Class<?>> ignoredDependencyInterfaces = new HashSet<>();
public AbstractAutowireCapableBeanFactory() {
super();
//自动装配时忽略给定的依赖接口，典型应用是通过其他方式解析Application上下文注册依赖，
// 类似BeanFactory通过BeanFactoryAware进行诸如或者ApplicationContext通过ApplicationContextAware进行注入
ignoreDependencyInterface(BeanNameAware.class);
ignoreDependencyInterface(BeanFactoryAware.class);
ignoreDependencyInterface(BeanClassLoaderAware.class);
}
//设置初始化策略
public void setInstantiationStrategy(InstantiationStrategy instantiationStrategy) {
this.instantiationStrategy = instantiationStrategy;
}
//获得初始化策略
protected InstantiationStrategy getInstantiationStrategy() {
return this.instantiationStrategy;
}
//创建bean并且初始化
public <T> T createBean(Class<T> beanClass) throws BeansException {
// Use prototype bean definition, to avoid registering bean as dependent bean.
RootBeanDefinition bd = new RootBeanDefinition(beanClass);
bd.setScope(SCOPE_PROTOTYPE);
bd.allowCaching = ClassUtils.isCacheSafe(beanClass, getBeanClassLoader());
return (T) createBean(beanClass.getName(), bd, null);
}
//给bean populate属性
public void autowireBean(Object existingBean) {
// Use non-singleton bean definition, to avoid registering bean as dependent bean.
RootBeanDefinition bd = new RootBeanDefinition(ClassUtils.getUserClass(existingBean));
bd.setScope(BeanDefinition.SCOPE_PROTOTYPE);
bd.allowCaching = ClassUtils.isCacheSafe(bd.getBeanClass(), getBeanClassLoader());
BeanWrapper bw = new BeanWrapperImpl(existingBean);
initBeanWrapper(bw);
populateBean(bd.getBeanClass().getName(), bd, bw);
}
//给bean populate属性以及调用初始化方法
public Object configureBean(Object existingBean, String beanName) throws BeansException {
markBeanAsCreated(beanName);
BeanDefinition mbd = getMergedBeanDefinition(beanName);
RootBeanDefinition bd = null;
if (mbd instanceof RootBeanDefinition) {
RootBeanDefinition rbd = (RootBeanDefinition) mbd;
bd = (rbd.isPrototype() ? rbd : rbd.cloneBeanDefinition());
}
if (bd == null) {
bd = new RootBeanDefinition(mbd);
}
if (!bd.isPrototype()) {
bd.setScope(BeanDefinition.SCOPE_PROTOTYPE);
bd.allowCaching = ClassUtils.isCacheSafe(ClassUtils.getUserClass(existingBean), getBeanClassLoader());
}
BeanWrapper bw = new BeanWrapperImpl(existingBean);
initBeanWrapper(bw);
populateBean(beanName, bd, bw);
return initializeBean(beanName, existingBean, bd);
}
//依赖查找的核心方法，由DefaultListableBeanFactory实现
public Object resolveDependency(DependencyDescriptor descriptor, @Nullable String requestingBeanName) throws BeansException {
return resolveDependency(descriptor, requestingBeanName, null, null);
}
//创建bean并且实例化
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(BeanDefinition.SCOPE_PROTOTYPE);
return createBean(beanClass.getName(), bd, null);
}
//通过InstantiationStrategy实例化bean，并且populatebean的属性值
public Object autowire(Class<?> beanClass, int autowireMode, boolean dependencyCheck) throws BeansException {
// Use non-singleton bean definition, to avoid registering bean as dependent bean.
final RootBeanDefinition bd = new RootBeanDefinition(beanClass, autowireMode, dependencyCheck);
bd.setScope(BeanDefinition.SCOPE_PROTOTYPE);
if (bd.getResolvedAutowireMode() == AUTOWIRE_CONSTRUCTOR) {
return autowireConstructor(beanClass.getName(), bd, null, null).getWrappedInstance();
}
else {
Object bean;
final BeanFactory parent = this;
if (System.getSecurityManager() != null) {
bean = AccessController.doPrivileged((PrivilegedAction<Object>) () ->
getInstantiationStrategy().instantiate(bd, null, parent),
getAccessControlContext());
}
else {
bean = getInstantiationStrategy().instantiate(bd, null, parent);
}
populateBean(beanClass.getName(), bd, new BeanWrapperImpl(bean));
return bean;
}
}
//对于给定的bean，populate它的属性
public void autowireBeanProperties(Object existingBean, int autowireMode, boolean dependencyCheck)
throws BeansException {
if (autowireMode == AUTOWIRE_CONSTRUCTOR) {
throw new IllegalArgumentException("AUTOWIRE_CONSTRUCTOR not supported for existing bean instance");
}
// Use non-singleton bean definition, to avoid registering bean as dependent bean.
RootBeanDefinition bd =
new RootBeanDefinition(ClassUtils.getUserClass(existingBean), autowireMode, dependencyCheck);
bd.setScope(BeanDefinition.SCOPE_PROTOTYPE);
BeanWrapper bw = new BeanWrapperImpl(existingBean);
initBeanWrapper(bw);
populateBean(bd.getBeanClass().getName(), bd, bw);
}
//将beanName对应的BeanDefinition的属性值，复制给existingBean
public void applyBeanPropertyValues(Object existingBean, String beanName) throws BeansException {
markBeanAsCreated(beanName);
BeanDefinition bd = getMergedBeanDefinition(beanName);
BeanWrapper bw = new BeanWrapperImpl(existingBean);
initBeanWrapper(bw);
applyPropertyValues(beanName, bd, bw, bd.getPropertyValues());
}
//初始化Bean
public Object initializeBean(Object existingBean, String beanName) {
return initializeBean(beanName, existingBean, null);
}
//遍历BeanPostProcessors，调用PostProcessorsBeforeInitialization
public Object applyBeanPostProcessorsBeforeInitialization(Object existingBean, String beanName)
throws BeansException {
Object result = existingBean;
for (BeanPostProcessor processor : getBeanPostProcessors()) {
Object current = processor.postProcessBeforeInitialization(result, beanName);
if (current == null) {
return result;
}
result = current;
}
return result;
}
//遍历BeanPostProcessors，调用PBeanPostProcessorsAfterInitialization
public Object applyBeanPostProcessorsAfterInitialization(Object existingBean, String beanName)
throws BeansException {
Object result = existingBean;
for (BeanPostProcessor processor : getBeanPostProcessors()) {
Object current = processor.postProcessAfterInitialization(result, beanName);
if (current == null) {
return result;
}
result = current;
}
return result;
}
//销毁bean
public void destroyBean(Object existingBean) {
new DisposableBeanAdapter(existingBean, getBeanPostProcessors(), getAccessControlContext()).destroy();
}
//上面createBean的调用的方法
protected Object createBean(String beanName, RootBeanDefinition mbd, @Nullable Object[] args)
throws BeanCreationException {
RootBeanDefinition mbdToUse = mbd;
//获得beanName对应点class
Class<?> resolvedClass = resolveBeanClass(mbd, beanName);
if (resolvedClass != null && !mbd.hasBeanClass() && mbd.getBeanClassName() != null) {
mbdToUse = new RootBeanDefinition(mbd);
mbdToUse.setBeanClass(resolvedClass);
}
try {
mbdToUse.prepareMethodOverrides();
}
catch (BeanDefinitionValidationException ex) {
throw new BeanDefinitionStoreException(mbdToUse.getResourceDescription(),
beanName, "Validation of method overrides failed", ex);
}
try {
// Give BeanPostProcessors a chance to return a proxy instead of the target bean instance.
//在实例化之前给BeanPostProcessor机会进行处理
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 {
//调用doCreateBean去真正的创建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);
}
}
//真正createbean的方法
protected Object doCreateBean(final String beanName, final RootBeanDefinition mbd, final @Nullable Object[] args)
throws BeanCreationException {
BeanWrapper instanceWrapper = null;
if (mbd.isSingleton()) {
instanceWrapper = this.factoryBeanInstanceCache.remove(beanName);
}
if (instanceWrapper == null) {
//创建bean的实例
instanceWrapper = createBeanInstance(beanName, mbd, args);
}
final Object bean = instanceWrapper.getWrappedInstance();
Class<?> beanType = instanceWrapper.getWrappedClass();
if (beanType != NullBean.class) {
mbd.resolvedTargetType = beanType;
}
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);
}
mbd.postProcessed = true;
}
}
// 处理循环依赖的一个点，创建bean实例之后首先放入SingletonFactory缓存中
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");
}
addSingletonFactory(beanName, () -> getEarlyBeanReference(beanName, mbd, bean));
}
// Initialize the bean instance.
Object exposedObject = bean;
try {
//设置bean的属性
populateBean(beanName, mbd, instanceWrapper);
//初始化相应的bean
exposedObject = initializeBean(beanName, exposedObject, mbd);
}
catch (Throwable ex) {
if (ex instanceof BeanCreationException && beanName.equals(((BeanCreationException) ex).getBeanName())) {
throw (BeanCreationException) ex;
}
else {
throw new BeanCreationException(
mbd.getResourceDescription(), beanName, "Initialization of bean failed", ex);
}
}
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<>(dependentBeans.length);
for (String dependentBean : dependentBeans) {
if (!removeSingletonIfCreatedForTypeCheckOnly(dependentBean)) {
actualDependentBeans.add(dependentBean);
}
}
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 " +
"'getBeanNamesOfType' with the 'allowEagerInit' flag turned off, for example.");
}
}
}
}
// Register bean as disposable.
try {
registerDisposableBeanIfNecessary(beanName, bean, mbd);
}
catch (BeanDefinitionValidationException ex) {
throw new BeanCreationException(
mbd.getResourceDescription(), beanName, "Invalid destruction signature", ex);
}
return exposedObject;
}
//创建bean的实例
protected BeanWrapper createBeanInstance(String beanName, RootBeanDefinition mbd, @Nullable Object[] args) {
// 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());
}
Supplier<?> instanceSupplier = mbd.getInstanceSupplier();
if (instanceSupplier != null) {
return obtainFromSupplier(instanceSupplier, beanName);
}
if (mbd.getFactoryMethodName() != null) {
return instantiateUsingFactoryMethod(beanName, mbd, args);
}
// 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) {
return autowireConstructor(beanName, mbd, null, null);
}
else {
return instantiateBean(beanName, mbd);
}
}
// Candidate constructors for autowiring?
Constructor<?>[] ctors = determineConstructorsFromBeanPostProcessors(beanClass, beanName);
if (ctors != null || mbd.getResolvedAutowireMode() == AUTOWIRE_CONSTRUCTOR ||
mbd.hasConstructorArgumentValues() || !ObjectUtils.isEmpty(args)) {
return autowireConstructor(beanName, mbd, ctors, args);
}
// Preferred constructors for default construction?
ctors = mbd.getPreferredConstructors();
if (ctors != null) {
return autowireConstructor(beanName, mbd, ctors, null);
}
// No special handling: simply use no-arg constructor.
return instantiateBean(beanName, mbd);
}
//实例化Bean
protected BeanWrapper instantiateBean(final String beanName, final RootBeanDefinition mbd) {
try {
Object beanInstance;
final BeanFactory parent = this;
if (System.getSecurityManager() != null) {
beanInstance = AccessController.doPrivileged((PrivilegedAction<Object>) () ->
getInstantiationStrategy().instantiate(mbd, beanName, parent),
getAccessControlContext());
}
else {
beanInstance = getInstantiationStrategy().instantiate(mbd, beanName, parent);
}
BeanWrapper bw = new BeanWrapperImpl(beanInstance);
initBeanWrapper(bw);
return bw;
}
catch (Throwable ex) {
throw new BeanCreationException(
mbd.getResourceDescription(), beanName, "Instantiation of bean failed", ex);
}
}
//给对应的bean设置属性值
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;
}
}
boolean continueWithPropertyPopulation = true;
if (!mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) {
for (BeanPostProcessor bp : getBeanPostProcessors()) {
if (bp instanceof InstantiationAwareBeanPostProcessor) {
InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp;
if (!ibp.postProcessAfterInstantiation(bw.getWrappedInstance(), beanName)) {
continueWithPropertyPopulation = false;
break;
}
}
}
}
if (!continueWithPropertyPopulation) {
return;
}
PropertyValues pvs = (mbd.hasPropertyValues() ? mbd.getPropertyValues() : null);
//这里根据xml里面autowire值来判断如何注入的
if (mbd.getResolvedAutowireMode() == AUTOWIRE_BY_NAME || mbd.getResolvedAutowireMode() == AUTOWIRE_BY_TYPE) {
MutablePropertyValues newPvs = new MutablePropertyValues(pvs);
// Add property values based on autowire by name if applicable.
if (mbd.getResolvedAutowireMode() == AUTOWIRE_BY_NAME) {
autowireByName(beanName, mbd, bw, newPvs);
}
// Add property values based on autowire by type if applicable.
if (mbd.getResolvedAutowireMode() == AUTOWIRE_BY_TYPE) {
autowireByType(beanName, mbd, bw, newPvs);
}
pvs = newPvs;
}
boolean hasInstAwareBpps = hasInstantiationAwareBeanPostProcessors();
boolean needsDepCheck = (mbd.getDependencyCheck() != AbstractBeanDefinition.DEPENDENCY_CHECK_NONE);
PropertyDescriptor[] filteredPds = null;
if (hasInstAwareBpps) {
if (pvs == null) {
pvs = mbd.getPropertyValues();
}
//这里主要对应@autowired注解的处理
for (BeanPostProcessor bp : getBeanPostProcessors()) {
if (bp instanceof InstantiationAwareBeanPostProcessor) {
InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp;
PropertyValues pvsToUse = ibp.postProcessProperties(pvs, bw.getWrappedInstance(), beanName);
if (pvsToUse == null) {
if (filteredPds == null) {
filteredPds = filterPropertyDescriptorsForDependencyCheck(bw, mbd.allowCaching);
}
pvsToUse = ibp.postProcessPropertyValues(pvs, filteredPds, bw.getWrappedInstance(), beanName);
if (pvsToUse == null) {
return;
}
}
pvs = pvsToUse;
}
}
}
if (needsDepCheck) {
if (filteredPds == null) {
filteredPds = filterPropertyDescriptorsForDependencyCheck(bw, mbd.allowCaching);
}
checkDependencies(beanName, mbd, filteredPds, pvs);
}
if (pvs != null) {
拿到队形的pvs就开始设置到对应的属性
applyPropertyValues(beanName, mbd, bw, pvs);
}
}
//给bean设置对应的property value
protected void applyPropertyValues(String beanName, BeanDefinition mbd, BeanWrapper bw, PropertyValues pvs) {
if (pvs.isEmpty()) {
return;
}
if (System.getSecurityManager() != null && bw instanceof BeanWrapperImpl) {
((BeanWrapperImpl) bw).setSecurityContext(getAccessControlContext());
}
MutablePropertyValues mpvs = null;
List<PropertyValue> original;
if (pvs instanceof MutablePropertyValues) {
mpvs = (MutablePropertyValues) pvs;
if (mpvs.isConverted()) {
// Shortcut: use the pre-converted values as-is.
try {
bw.setPropertyValues(mpvs);
return;
}
catch (BeansException ex) {
throw new BeanCreationException(
mbd.getResourceDescription(), beanName, "Error setting property values", ex);
}
}
original = mpvs.getPropertyValueList();
}
else {
original = Arrays.asList(pvs.getPropertyValues());
}
TypeConverter converter = getCustomTypeConverter();
if (converter == null) {
converter = bw;
}
BeanDefinitionValueResolver valueResolver = new BeanDefinitionValueResolver(this, beanName, mbd, converter);
// 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()) {
deepCopy.add(pv);
}
else {
String propertyName = pv.getName();
Object originalValue = pv.getValue();
Object resolvedValue = valueResolver.resolveValueIfNecessary(pv, originalValue);
Object convertedValue = resolvedValue;
boolean convertible = bw.isWritableProperty(propertyName) &&
!PropertyAccessorUtils.isNestedOrIndexedProperty(propertyName);
if (convertible) {
convertedValue = convertForProperty(resolvedValue, propertyName, bw, converter);
}
// Possibly store converted value in merged bean definition,
// in order to avoid re-conversion for every created bean instance.
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));
}
}
}
if (mpvs != null && !resolveNecessary) {
mpvs.setConverted();
}
// Set our (possibly massaged) deep copy.
try {
bw.setPropertyValues(new MutablePropertyValues(deepCopy));
}
catch (BeansException ex) {
throw new BeanCreationException(
mbd.getResourceDescription(), beanName, "Error setting property values", ex);
}
}
//初始化bean实例
protected Object initializeBean(final String beanName, final Object bean, @Nullable RootBeanDefinition mbd) {
if (System.getSecurityManager() != null) {
AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
invokeAwareMethods(beanName, bean);
return null;
}, getAccessControlContext());
}
else {
//调用相应的aware方法，比如BeanFactoryAware，来设置BeanFactory属性
invokeAwareMethods(beanName, bean);
}
Object wrappedBean = bean;
if (mbd == null || !mbd.isSynthetic()) {
//调用初始化方法之前调用BeanPostProcessorsBeforeInitialization
wrappedBean = applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName);
}
try {
//调用初始化方法，包括afterProperty()以及customer初始化方法
invokeInitMethods(beanName, wrappedBean, mbd);
}
catch (Throwable ex) {
throw new BeanCreationException(
(mbd != null ? mbd.getResourceDescription() : null),
beanName, "Invocation of init method failed", ex);
}
if (mbd == null || !mbd.isSynthetic()) {
//调用初始化方法之后调用BeanPostProcessorsAfterInitialization
wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);
}
return wrappedBean;
}
}
