Spring依赖注入之@Autowired、@Qualifier、@Primary、@Priority注解原理（上）
- Autowired等注解
- Spring依赖注入之@Autowired、@Qualifier、@Primary、@Priority注解用法
- Spring依赖注入之@Autowired、@Qualifier、@Primary、@Priority注解原理（上）
- Spring依赖注入之@Autowired、@Qualifier、@Primary、@Priority注解原理（下）
- Value注解
- 依赖注入之@Value原理（整体流程）
- 依赖注入之@Value原理（获取value值）
- 依赖注入之@Value原理（placeholder解析）
- 依赖注入之@Value原理（SpEL表达式解析）
- Lookup注解
- Spring Boot依赖注入之Lookup注解
@Autowired注解可以声明一个bean依赖的其他bean，spring在创建bean时会将这些依赖的bean注入进来，涉及到的注解有@Autowired、@Value、@Qualifier、@Primary、@Priority几个注解。@Autowired注解可以使用在Field、Constructor、Method上来注入依赖，本质上只是使用地方不同，最终都会通过AutowireCapableBeanFactory#resolveDependency方法解析出依赖的实例。本节分析标注在Field、Constructor、Method上的@Autowired注解是如何起作用的
1、Field&Method上的@Autowired注解
Field和Method上的@Autowired注解都是在bean实例化之后，通过AutowiredAnnotationBeanPostProcessor#postProcessProperties方法进行注入的。这个方法中首先回解析出所有带有@Autowired的Field和Method，然后分别进行注入，如下
public PropertyValues postProcessProperties(PropertyValues pvs, Object bean, String beanName) {
InjectionMetadata metadata = findAutowiringMetadata(beanName, bean.getClass(), pvs);
try {
metadata.inject(bean, beanName, pvs);
}
catch (BeanCreationException ex) {
throw ex;
}
catch (Throwable ex) {
throw new BeanCreationException(beanName, "Injection of autowired dependencies failed", ex);
}
return pvs;
}
InjectionMetadata就是包装了将要注入依赖的targetClass和要注入以来的对象InjectedElement，就是Field或Method
public class InjectionMetadata {
private final Class<?> targetClass;
private final Collection<InjectedElement> injectedElements;
}
InjectedElement是要注入的目标，member是Constructor、Method、Field的父类，isField标识是否是Field
public abstract static class InjectedElement {
protected final Member member;
protected final boolean isField;
}
InjectedElement有两个子类，AutowiredFieldElement和AutowiredMethodElement，required即@Autowired注解的required字段；cached、cachedFieldValue、cachedMethodArguments涉及缓存逻辑
private class AutowiredFieldElement extends InjectionMetadata.InjectedElement {
private final boolean required;
private volatile boolean cached;
@Nullable
private volatile Object cachedFieldValue;
}
private class AutowiredMethodElement extends InjectionMetadata.InjectedElement {
private final boolean required;
private volatile boolean cached;
@Nullable
private volatile Object[] cachedMethodArguments;
}
a、注解的解析
findAutowiringMetadata方法中处理了缓存逻辑，然后调用buildAutowiringMetadata真正去解析@Autowired注解
private InjectionMetadata buildAutowiringMetadata(Class<?> clazz) {
if (!AnnotationUtils.isCandidateClass(clazz, this.autowiredAnnotationTypes)) {
return InjectionMetadata.EMPTY;
}
List<InjectionMetadata.InjectedElement> elements = new ArrayList<>();
Class<?> targetClass = clazz;
do {
final List<InjectionMetadata.InjectedElement> currElements = new ArrayList<>();
ReflectionUtils.doWithLocalFields(targetClass, field -> {
MergedAnnotation<?> ann = findAutowiredAnnotation(field);
if (ann != null) {
if (Modifier.isStatic(field.getModifiers())) {
if (logger.isInfoEnabled()) {
logger.info("Autowired annotation is not supported on static fields: " + field);
}
return;
}
boolean required = determineRequiredStatus(ann);
currElements.add(new AutowiredFieldElement(field, required));
}
});
ReflectionUtils.doWithLocalMethods(targetClass, method -> {
Method bridgedMethod = BridgeMethodResolver.findBridgedMethod(method);
if (!BridgeMethodResolver.isVisibilityBridgeMethodPair(method, bridgedMethod)) {
return;
}
MergedAnnotation<?> ann = findAutowiredAnnotation(bridgedMethod);
if (ann != null && method.equals(ClassUtils.getMostSpecificMethod(method, clazz))) {
if (Modifier.isStatic(method.getModifiers())) {
if (logger.isInfoEnabled()) {
logger.info("Autowired annotation is not supported on static methods: " + method);
}
return;
}
if (method.getParameterCount() == 0) {
if (logger.isInfoEnabled()) {
logger.info("Autowired annotation should only be used on methods with parameters: " +
method);
}
}
boolean required = determineRequiredStatus(ann);
PropertyDescriptor pd = BeanUtils.findPropertyForMethod(bridgedMethod, clazz);
currElements.add(new AutowiredMethodElement(method, required, pd));
}
});
elements.addAll(0, currElements);
targetClass = targetClass.getSuperclass();
}
while (targetClass != null && targetClass != Object.class);
return InjectionMetadata.forElements(elements, clazz);
}
Field依赖解析
buildAutowiringMetadata的do-while大循环里遍历targetClass及所有父类，解析其中的Field和Method，然后将解析结果包装成InjectionMetadata返回。
解析Field时，其逻辑比较简单，通过findAutowiredAnnotation解析每一个Field上的注解，会查找三个注解
- @Autowired
- @Value
- @Inject
如果存在的话，再解析一下required字段
Method依赖解析
解析Method时，总体逻辑跟Field类似，通过findAutowiredAnnotation解析每一个Meathod上的注解，同样也会查找@Autowired、@Value、@Inject三个注解，然后解析required字段。解析方法时，没有对方法名做任何假设，setter方法只是其中一个特例，@Autowired方法可以不是setter。最终将Field、Method解析结果放到InjectionMetadata一起返回。
方法的解析，由于存在方法的重写、接口默认方法、桥接方法，要考虑的问题要复杂很多。
具体遍历哪些方法
private static Method[] getDeclaredMethods(Class<?> clazz, boolean defensive) {
Assert.notNull(clazz, "Class must not be null");
Method[] result = declaredMethodsCache.get(clazz);
if (result == null) {
try {
Method[] declaredMethods = clazz.getDeclaredMethods();
List<Method> defaultMethods = findConcreteMethodsOnInterfaces(clazz);
if (defaultMethods != null) {
result = new Method[declaredMethods.length + defaultMethods.size()];
System.arraycopy(declaredMethods, 0, result, 0, declaredMethods.length);
int index = declaredMethods.length;
for (Method defaultMethod : defaultMethods) {
result[index] = defaultMethod;
index++;
}
}
else {
result = declaredMethods;
}
declaredMethodsCache.put(clazz, (result.length == 0 ? EMPTY_METHOD_ARRAY : result));
}
catch (Throwable ex) {
throw new IllegalStateException("Failed to introspect Class [" + clazz.getName() +
"] from ClassLoader [" + clazz.getClassLoader() + "]", ex);
}
}
return (result.length == 0 || !defensive) ? result : result.clone();
}
doWithLocalMethods方法会遍历这个类的declaredMethod和这个类的所有接口的默认方法。
bridge方法的处理
BridgeMethodResolver#findBridgedMethod找到当前方法的被bridge的方法，如果当前方法不是bridge方法，则返回这个方法本身。
BridgeMethodResolver#isVisibilityBridgeMethodPair会过滤掉bridge方法
public static boolean isVisibilityBridgeMethodPair(Method bridgeMethod, Method bridgedMethod) {
if (bridgeMethod == bridgedMethod) {
return true;
}
return (bridgeMethod.getReturnType().equals(bridgedMethod.getReturnType()) &&
bridgeMethod.getParameterCount() == bridgedMethod.getParameterCount() &&
Arrays.equals(bridgeMethod.getParameterTypes(), bridgedMethod.getParameterTypes()));
}
这里应当是有三种情况：
- 如果bridgeMethod是一个普通方法（不是bridge方法），那么bridgeMethod==bridgedMethod，返回true，外部需要处理这个方法
- 如果bridgeMethod是一个bridge方法，但是是由于可见性问题引入的bridge方法，返回true，外部来解析这个bridge方法（后续依赖注入时也会调用这个bridge方法，是因为直接调用原方法的话会由于无法访问抛出异常）
- 如果bridgeMethod是一个bridge方法，但是是由于方法重写（重写时修改了返回类型、子类将泛型具体化）引入的桥接方法，那么返回false，外部不要处理这个方法，而是去处理这个方法的被桥接的方法
bridge方法这里解释的不够，后面专门讲bridge方法
方法重写的处理
当子类重写了父类方法，依赖的解析应当忽略父类方法而解析子类方法。但是doWithLocalMethods会遍历父类的所有方法，遍历到父类方法是如何知道应当忽略的呢？
if (ann != null && method.equals(ClassUtils.getMostSpecificMethod(method, clazz)))
当这个方法存在依赖注入注解并且method.equals(ClassUtils.getMostSpecificMethod(method, clazz))才会去处理这个方法。ClassUtils#getMostSpecificMethod这个方法会顺着类继承层次从clazz开始往上找一个同名同参方法，如果method和这个同名同参方法相等，说明这个方法没有被重写，是需要处理的。
b、依赖注入
postProcessProperties方法中，先解析出来InjectionMetadata后，调用InjectionMetadata#inject完成对Field、Method的注入。
public void inject(Object target, @Nullable String beanName, @Nullable PropertyValues pvs) throws Throwable {
Collection<InjectedElement> checkedElements = this.checkedElements;
Collection<InjectedElement> elementsToIterate =
(checkedElements != null ? checkedElements : this.injectedElements);
if (!elementsToIterate.isEmpty()) {
for (InjectedElement element : elementsToIterate) {
element.inject(target, beanName, pvs);
}
}
}
InjectionMetadata#inject方法就是遍历了每一个element进行注入，每个element有两种情况：AutowiredFieldElement和AutowiredMethodElement。
Field的依赖注入
protected void inject(Object bean, @Nullable String beanName, @Nullable PropertyValues pvs) throws Throwable {
Field field = (Field) this.member;
Object value;
if (this.cached) {
try {
value = resolvedCachedArgument(beanName, this.cachedFieldValue);
}
catch (NoSuchBeanDefinitionException ex) {
// Unexpected removal of target bean for cached argument -> re-resolve
value = resolveFieldValue(field, bean, beanName);
}
}
else {
value = resolveFieldValue(field, bean, beanName);
}
if (value != null) {
ReflectionUtils.makeAccessible(field);
field.set(bean, value);
}
}
除去缓存逻辑之外，就是调用resolveFieldValue解析出value，如果不为null的话通过反射set进去，如果为null则不处理。这样可以设置required=false然后给一个默认值，如果不存在就为默认值。
private Object resolveFieldValue(Field field, Object bean, @Nullable String beanName) {
DependencyDescriptor desc = new DependencyDescriptor(field, this.required);
desc.setContainingClass(bean.getClass());
Set<String> autowiredBeanNames = new LinkedHashSet<>(1);
Assert.state(beanFactory != null, "No BeanFactory available");
TypeConverter typeConverter = beanFactory.getTypeConverter();
Object value;
try {
value = beanFactory.resolveDependency(desc, beanName, autowiredBeanNames, typeConverter);
}
catch (BeansException ex) {
throw new UnsatisfiedDependencyException(null, beanName, new InjectionPoint(field), ex);
}
synchronized (this) {
if (!this.cached) {
Object cachedFieldValue = null;
if (value != null || this.required) {
cachedFieldValue = desc;
registerDependentBeans(beanName, autowiredBeanNames);
if (autowiredBeanNames.size() == 1) {
String autowiredBeanName = autowiredBeanNames.iterator().next();
if (beanFactory.containsBean(autowiredBeanName) &&
beanFactory.isTypeMatch(autowiredBeanName, field.getType())) {
cachedFieldValue = new ShortcutDependencyDescriptor(
desc, autowiredBeanName, field.getType());
}
}
}
this.cachedFieldValue = cachedFieldValue;
this.cached = true;
}
}
return value;
}
}
resolveFieldValue调用AutowireCapableBeanFactory#resolveDependency解析出要注入的bean，这里面统一处理了@Autowired、@Value、@Inject三个注解，具体逻辑下节分析
Method的依赖注入
protected void inject(Object bean, @Nullable String beanName, @Nullable PropertyValues pvs) throws Throwable {
if (checkPropertySkipping(pvs)) {
return;
}
Method method = (Method) this.member;
Object[] arguments;
if (this.cached) {
try {
arguments = resolveCachedArguments(beanName);
}
catch (NoSuchBeanDefinitionException ex) {
// Unexpected removal of target bean for cached argument -> re-resolve
arguments = resolveMethodArguments(method, bean, beanName);
}
}
else {
arguments = resolveMethodArguments(method, bean, beanName);
}
if (arguments != null) {
try {
ReflectionUtils.makeAccessible(method);
method.invoke(bean, arguments);
}
catch (InvocationTargetException ex) {
throw ex.getTargetException();
}
}
}
inject方法调用resolveMethodArguments解析出每一个参数，通过反射调用这个方法。
private Object[] resolveMethodArguments(Method method, Object bean, @Nullable String beanName) {
int argumentCount = method.getParameterCount();
Object[] arguments = new Object[argumentCount];
DependencyDescriptor[] descriptors = new DependencyDescriptor[argumentCount];
Set<String> autowiredBeans = new LinkedHashSet<>(argumentCount);
Assert.state(beanFactory != null, "No BeanFactory available");
TypeConverter typeConverter = beanFactory.getTypeConverter();
for (int i = 0; i < arguments.length; i++) {
MethodParameter methodParam = new MethodParameter(method, i);
DependencyDescriptor currDesc = new DependencyDescriptor(methodParam, this.required);
currDesc.setContainingClass(bean.getClass());
descriptors[i] = currDesc;
try {
Object arg = beanFactory.resolveDependency(currDesc, beanName, autowiredBeans, typeConverter);
if (arg == null && !this.required) {
arguments = null;
break;
}
arguments[i] = arg;
}
catch (BeansException ex) {
throw new UnsatisfiedDependencyException(null, beanName, new InjectionPoint(methodParam), ex);
}
}
synchronized (this) {
if (!this.cached) {
if (arguments != null) {
DependencyDescriptor[] cachedMethodArguments = Arrays.copyOf(descriptors, arguments.length);
registerDependentBeans(beanName, autowiredBeans);
if (autowiredBeans.size() == argumentCount) {
Iterator<String> it = autowiredBeans.iterator();
Class<?>[] paramTypes = method.getParameterTypes();
for (int i = 0; i < paramTypes.length; i++) {
String autowiredBeanName = it.next();
if (beanFactory.containsBean(autowiredBeanName) &&
beanFactory.isTypeMatch(autowiredBeanName, paramTypes[i])) {
cachedMethodArguments[i] = new ShortcutDependencyDescriptor(
descriptors[i], autowiredBeanName, paramTypes[i]);
}
}
}
this.cachedMethodArguments = cachedMethodArguments;
}
else {
this.cachedMethodArguments = null;
}
this.cached = true;
}
}
return arguments;
}
}
方法注入逻辑也不复杂，for循环遍历每个paramter，调用AutowireCapableBeanFactory#resolveDependency解析出每个Parameter的bean。至于Parameter上的required是如何覆盖方法上的required的，逻辑涉及到AutowireCapableBeanFactory#resolveDependency，先贴上结论后面分析：Parameter上required=false可以覆盖方法上的required=true，Parameter上required=true不能覆盖方法上的required=false，即
- 方法上required=true，Parameter上required=false，Parameter最终的required=false
- 方法上required=false，Parameter上required=true，Parameter最终的required=false
当参数最终required=false时，AutowireCapableBeanFactory#resolveDependency会返回null。
再看注入逻辑，方法的注入逻辑也比较特殊：
- 如果方法required=false，有一个参数的bean不存在，全都不会注入
- 如果方法required=true，如果参数bean不存在，则该参数注入null（即不能设置默认值了）
2、Constructor上的@Autowired注解
AbstractAutowireCapableBeanFactory在通过AbstractAutowireCapableBeanFactory#createBeanInstance方法创建bean实例时，首先会尝试通过InstanceSupplier创建，其次尝试通过FactoryMethod，再次尝试通过有参构造器来创建，最后通过无参构造器创建。
通过有参构造器方式创建时，先通过determineConstructorsFromBeanPostProcessors选择一个有参构造器出来，然后通过autowireConstructor注入以来并通过有参构造器创建对象。
Constructor<?>[] ctors = determineConstructorsFromBeanPostProcessors(beanClass, beanName);
if (ctors != null || mbd.getResolvedAutowireMode() == AUTOWIRE_CONSTRUCTOR ||
mbd.hasConstructorArgumentValues() || !ObjectUtils.isEmpty(args)) {
return autowireConstructor(beanName, mbd, ctors, args);
}
a、有参构造器的选择
determineConstructorsFromBeanPostProcessors遍历了InstantiationAwareBeanPostProcessor，有一个选择出Constructor就返回。最终会调用到AutowiredAnnotationBeanPostProcessor#determineCandidateConstructors
protected Constructor<?>[] determineConstructorsFromBeanPostProcessors(@Nullable Class<?> beanClass, String beanName)
throws BeansException {
if (beanClass != null && hasInstantiationAwareBeanPostProcessors()) {
for (SmartInstantiationAwareBeanPostProcessor bp : getBeanPostProcessorCache().smartInstantiationAware) {
Constructor<?>[] ctors = bp.determineCandidateConstructors(beanClass, beanName);
if (ctors != null) {
return ctors;
}
}
}
return null;
}
AutowiredAnnotationBeanPostProcessor#determineCandidateConstructors逻辑很长，总体上来说就是找到一个有依赖注入注解的构造器，如下
public Constructor<?>[] determineCandidateConstructors(Class<?> beanClass, final String beanName)
throws BeanCreationException {
// 忽略掉 Lookup逻辑
// Quick check on the concurrent map first, with minimal locking.
Constructor<?>[] candidateConstructors = this.candidateConstructorsCache.get(beanClass);
if (candidateConstructors == null) {
// Fully synchronized resolution now...
synchronized (this.candidateConstructorsCache) {
candidateConstructors = this.candidateConstructorsCache.get(beanClass);
if (candidateConstructors == null) {
Constructor<?>[] rawCandidates;
try {
rawCandidates = beanClass.getDeclaredConstructors();
}
catch (Throwable ex) {
throw new BeanCreationException(beanName,
"Resolution of declared constructors on bean Class [" + beanClass.getName() +
"] from ClassLoader [" + beanClass.getClassLoader() + "] failed", ex);
}
List<Constructor<?>> candidates = new ArrayList<>(rawCandidates.length);
Constructor<?> requiredConstructor = null;
Constructor<?> defaultConstructor = null;
Constructor<?> primaryConstructor = BeanUtils.findPrimaryConstructor(beanClass);
int nonSyntheticConstructors = 0;
for (Constructor<?> candidate : rawCandidates) {
if (!candidate.isSynthetic()) {
nonSyntheticConstructors++;
}
else if (primaryConstructor != null) {
continue;
}
MergedAnnotation<?> ann = findAutowiredAnnotation(candidate);
if (ann == null) {
Class<?> userClass = ClassUtils.getUserClass(beanClass);
if (userClass != beanClass) {
try {
Constructor<?> superCtor =
userClass.getDeclaredConstructor(candidate.getParameterTypes());
ann = findAutowiredAnnotation(superCtor);
}
catch (NoSuchMethodException ex) {
// Simply proceed, no equivalent superclass constructor found...
}
}
}
if (ann != null) {
if (requiredConstructor != null) {
throw new BeanCreationException(beanName,
"Invalid autowire-marked constructor: " + candidate +
". Found constructor with 'required' Autowired annotation already: " +
requiredConstructor);
}
boolean required = determineRequiredStatus(ann);
if (required) {
if (!candidates.isEmpty()) {
throw new BeanCreationException(beanName,
"Invalid autowire-marked constructors: " + candidates +
". Found constructor with 'required' Autowired annotation: " +
candidate);
}
requiredConstructor = candidate;
}
candidates.add(candidate);
}
else if (candidate.getParameterCount() == 0) {
defaultConstructor = candidate;
}
}
if (!candidates.isEmpty()) {
// Add default constructor to list of optional constructors, as fallback.
if (requiredConstructor == null) {
if (defaultConstructor != null) {
candidates.add(defaultConstructor);
}
else if (candidates.size() == 1 && logger.isInfoEnabled()) {
logger.info("Inconsistent constructor declaration on bean with name '" + beanName +
"': single autowire-marked constructor flagged as optional - " +
"this constructor is effectively required since there is no " +
"default constructor to fall back to: " + candidates.get(0));
}
}
candidateConstructors = candidates.toArray(new Constructor<?>[0]);
}
else if (rawCandidates.length == 1 && rawCandidates[0].getParameterCount() > 0) {
candidateConstructors = new Constructor<?>[] {rawCandidates[0]};
}
else if (nonSyntheticConstructors == 2 && primaryConstructor != null &&
defaultConstructor != null && !primaryConstructor.equals(defaultConstructor)) {
candidateConstructors = new Constructor<?>[] {primaryConstructor, defaultConstructor};
}
else if (nonSyntheticConstructors == 1 && primaryConstructor != null) {
candidateConstructors = new Constructor<?>[] {primaryConstructor};
}
else {
candidateConstructors = new Constructor<?>[0];
}
this.candidateConstructorsCache.put(beanClass, candidateConstructors);
}
}
}
return (candidateConstructors.length > 0 ? candidateConstructors : null);
}
for循环遍历所有的构造器，查找构造器上的依赖注入注解包括@Autowired、@Inject、@Value。由于这个类可能是CGLIB生成的，导致构造器上没有这些注解，所以还会找出UserClass，查找注解。然后处理查找结果（忽略kotlin相关逻辑）
- 如果刚好找到一个构造器，返回
- 如果找到多于一个构造器，抛出异常
- 找不到构造器的情况下，如果只有这个类只有一个构造器，并且是有参构造器，返回这个有参构造器
- 返回null
b、有参构造器注入依赖
找到有参构造器之后，就通过ConstructorResolver#autowireConstructor进行依赖注入，并实例化这个对象。ConstructorResolver#autowireConstructor代码很长，简单来说就是通过ConstructorResolver#createArgumentArray方法解析出构造器中每个参数的依赖，然后通过ConstructorResolver#instantiate方法实例化这个对象。
解析参数依赖
ConstructorResolver#createArgumentArray遍历每一个参数，首先尝试从resolvedValues找到依赖（由于autowireConstructor传过来的explicitArgs为null），所以这里找不到。然后通过ConstructorResolver#resolveAutowiredArgument方法从beanFactory里解析出依赖
protected Object resolveAutowiredArgument(MethodParameter param, String beanName,
@Nullable Set<String> autowiredBeanNames, TypeConverter typeConverter, boolean fallback) {
Class<?> paramType = param.getParameterType();
if (InjectionPoint.class.isAssignableFrom(paramType)) {
InjectionPoint injectionPoint = currentInjectionPoint.get();
if (injectionPoint == null) {
throw new IllegalStateException("No current InjectionPoint available for " + param);
}
return injectionPoint;
}
try {
return this.beanFactory.resolveDependency(
new DependencyDescriptor(param, true), beanName, autowiredBeanNames, typeConverter);
}
catch (NoUniqueBeanDefinitionException ex) {
throw ex;
}
catch (NoSuchBeanDefinitionException ex) {
if (fallback) {
// Single constructor or factory method -> let's return an empty array/collection
// for e.g. a vararg or a non-null List/Set/Map parameter.
if (paramType.isArray()) {
return Array.newInstance(paramType.getComponentType(), 0);
}
else if (CollectionFactory.isApproximableCollectionType(paramType)) {
return CollectionFactory.createCollection(paramType, 0);
}
else if (CollectionFactory.isApproximableMapType(paramType)) {
return CollectionFactory.createMap(paramType, 0);
}
}
throw ex;
}
}
resolveAutowiredArgument也是通过beanFactory#resolveDependency解析出依赖
实例化
bean的实例化委托给了InstantiationStrategy类来创建，这个的实现分析Lookup时分析过
private Object instantiate(
String beanName, RootBeanDefinition mbd, Constructor<?> constructorToUse, Object[] argsToUse) {
try {
InstantiationStrategy strategy = this.beanFactory.getInstantiationStrategy();
if (System.getSecurityManager() != null) {
return AccessController.doPrivileged((PrivilegedAction<Object>) () ->
strategy.instantiate(mbd, beanName, this.beanFactory, constructorToUse, argsToUse),
this.beanFactory.getAccessControlContext());
}
else {
return strategy.instantiate(mbd, beanName, this.beanFactory, constructorToUse, argsToUse);
}
}
catch (Throwable ex) {
throw new BeanCreationException(mbd.getResourceDescription(), beanName,
"Bean instantiation via constructor failed", ex);
}
}