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protected Object doCreateBean(String beanName, RootBeanDefinition mbd, @Nullable Object[] args) {
// 实例化bean
BeanWrapper instanceWrapper = createBeanInstance(beanName, mbd, args);
// 属性填充
populateBean(beanName, mbd, instanceWrapper);
// 调用初始化方法
return initializeBean(beanName, instanceWrapper.getWrappedInstance(), mbd);
}
创建实例-createBeanInstance
/**
* 使用适当的实例化策略为指定的 bean 创建一个新实例：
* 工厂方法、构造函数自动装配或简单实例化。
* @param beanName bean 的名称
* @param mbd bean 的 bean 定义
* @param args 用于构造函数或工厂方法调用的显式参数
* @return 新实例的 BeanWrapper
* @see #obtainFromSupplier
* @see #instantiateUsingFactoryMethod
* @see #autowireConstructor
* @see #instantiateBean
*/
protected BeanWrapper createBeanInstance(String beanName, RootBeanDefinition mbd, @Nullable Object[] args) {
// 确保此时真正解析了 bean 类。
Class<?> beanClass = resolveBeanClass(mbd, beanName);
// 校验这个instanceSupplier是否有值，有的话，调用这个字段获取对象。
// 工厂方法创建对象使用反射调用目标方法，不如直接调用目标方法效率高
Supplier<?> instanceSupplier = mbd.getInstanceSupplier();
if (instanceSupplier != null) {
return obtainFromSupplier(instanceSupplier, beanName);
}
// 如果工厂方法不为空则使用工厂方法初始化策略
if (mbd.getFactoryMethodName() != null) {
// 1、RootBeanDefinition 中存在 factoryMethodName属性，或配置文件中配置了factory-method，根据配置生成实例
return instantiateUsingFactoryMethod(beanName, mbd, args);
}
// 重新创建同一个 bean 时的快捷方式...
boolean resolved = false;
boolean autowireNecessary = false;
if (args == null) {
synchronized (mbd.constructorArgumentLock) {
// 2、判断过程很耗性能，采用缓存机制，RootBeanDefinition中的属性resolvedConstructorOrFactoryMethod缓存中去取
// 根据参数及类型锁定对应的构造函数或工厂方法
if (mbd.resolvedConstructorOrFactoryMethod != null) {
resolved = true;
autowireNecessary = mbd.constructorArgumentsResolved;
}
}
}
// 如果已经解析过则使用解析好的构造函数不需要再次锁定
if (resolved) {
if (autowireNecessary) {
// 构造函数自动注入
return autowireConstructor(beanName, mbd, null, null);
} else {
// 默认构造函数构造
return instantiateBean(beanName, mbd);
}
}
// 根据参数解析构造函数
// 自动装配的候选构造函数？
Constructor<?>[] ctors = determineConstructorsFromBeanPostProcessors(beanClass, beanName);
if (ctors != null || mbd.getResolvedAutowireMode() == AUTOWIRE_CONSTRUCTOR ||
mbd.hasConstructorArgumentValues() || !ObjectUtils.isEmpty(args)) {
// 构造函数自动注入
return autowireConstructor(beanName, mbd, ctors, args);
}
// 没有特殊处理：只需使用无参数构造函数。
return instantiateBean(beanName, mbd);
}
有参构造-autowireConstructor
1、构造函数参数的确定
1)根据explicitArgs参数判断
2)缓存中获取
3)配置文件获取
2、构造函数的确定
3、根据确定的构造函数转换对应的参数类型
4、构造函数不确定性的验证
因为不同构造函数的参数为父子关系
5、根据实例化策略以及得到的构造函数及其参数实例化Bean
/**
* “自动装配构造函数”（按类型使用构造函数参数）行为。
* 如果指定了显式构造函数参数值，也适用，将所有剩余参数与来自 bean 工厂的 bean 匹配。
* 这对应于构造函数注入：在这种模式下，Spring bean 工厂能够承载期望基于构造函数的依赖项解析的组件。
* @param beanName bean 的名称
* @param mbd bean 的 bean 定义
* @param chosenCtors 选择的候选构造函数
* @param explicitArgs 参数值通过 getBean 方法以编程方式传入，或者 {@code null} 如果没有（-> 使用 bean 定义中的构造函数参数值）
* @return 新实例的 BeanWrapper
*/
public BeanWrapper autowireConstructor(String beanName, RootBeanDefinition mbd,
@Nullable Constructor<?>[] chosenCtors, @Nullable Object[] explicitArgs) {
BeanWrapperImpl bw = new BeanWrapperImpl();
this.beanFactory.initBeanWrapper(bw);
Constructor<?> constructorToUse = null;
ArgumentsHolder argsHolderToUse = null;
Object[] argsToUse = null;
// explicitArgs 通过getBean()传入
if (explicitArgs != null) {
// 如果 getBean() 调用的时候指定方法参数那么直接使用
argsToUse = explicitArgs;
} else {
// 如果 getBean() 调用的时候没有指定方法参数，则尝试从配置文件中解析
Object[] argsToResolve = null;
// 尝试从缓存中获取
synchronized (mbd.constructorArgumentLock) {
constructorToUse = (Constructor<?>) mbd.resolvedConstructorOrFactoryMethod;
if (constructorToUse != null && mbd.constructorArgumentsResolved) {
// 从缓存中取
// 找到一个缓存的构造函数...
argsToUse = mbd.resolvedConstructorArguments;
if (argsToUse == null) {
// 配置的构造函数参数
argsToResolve = mbd.preparedConstructorArguments;
}
}
}
// 如果缓存中存在
if (argsToResolve != null) {
// 解析参数类型，如给定方法的构造函数A(int,int)通过此方法后就会把配置中的("1","1")转换为(1,1)
// 缓存中的值可能是原始值或者最终值
argsToUse = resolvePreparedArguments(beanName, mbd, bw, constructorToUse, argsToResolve);
}
}
// 没有被缓存
if (constructorToUse == null) {
// 需要解析构造函数.
boolean autowiring = (chosenCtors != null ||
mbd.getResolvedAutowireMode() == AutowireCapableBeanFactory.AUTOWIRE_CONSTRUCTOR);
ConstructorArgumentValues resolvedValues = null;
int minNrOfArgs;
if (explicitArgs != null) {
minNrOfArgs = explicitArgs.length;
} else {
// 提取配置文件中的配置的构造函数参数
ConstructorArgumentValues cargs = mbd.getConstructorArgumentValues();
// 用于承载解析后的构造函数参数的值
resolvedValues = new ConstructorArgumentValues();
// 能解析到的参数个数
minNrOfArgs = resolveConstructorArguments(beanName, mbd, bw, cargs, resolvedValues);
}
// 使用指定的构造函数，如果有的话。
Constructor<?>[] candidates = chosenCtors;
if (candidates == null) {
Class<?> beanClass = mbd.getBeanClass();
candidates = (mbd.isNonPublicAccessAllowed() ?
beanClass.getDeclaredConstructors() : beanClass.getConstructors());
}
// 排序给定的构造函数，public构造函数优先参数数量降序、非public构造函数参数数量降序
AutowireUtils.sortConstructors(candidates);
int minTypeDiffWeight = Integer.MAX_VALUE;
Set<Constructor<?>> ambiguousConstructors = null;
LinkedList<UnsatisfiedDependencyException> causes = null;
for (Constructor<?> candidate : candidates) {
Class<?>[] paramTypes = candidate.getParameterTypes();
if (constructorToUse != null && argsToUse.length > paramTypes.length) {
// 如果已经找到选用的构造函数或者需要的参数个数小于当前的构造函数参数个数则终止
// 已经找到了可以满足的贪婪构造函数 -> 不要再看了，只剩下更少的贪婪构造函数了。
break;
}
if (paramTypes.length < minNrOfArgs) {
// 参数个数不相等
continue;
}
ArgumentsHolder argsHolder;
if (resolvedValues != null) {
// 有参数则根据值构造对应参数类型的参数
try {
// 注释上获取参数名称
String[] paramNames = ConstructorPropertiesChecker.evaluate(candidate, paramTypes.length);
if (paramNames == null) {
// 获取参数名称探索器
ParameterNameDiscoverer pnd = this.beanFactory.getParameterNameDiscoverer();
if (pnd != null) {
// 获取指定构造函数的参数名称
paramNames = pnd.getParameterNames(candidate);
}
}
// 根据名称和数据类型创建参数持有者
argsHolder = createArgumentArray(beanName, mbd, resolvedValues, bw, paramTypes, paramNames,
getUserDeclaredConstructor(candidate), autowiring);
} catch (UnsatisfiedDependencyException ex) {
// 添加并尝试下一个构造函数。
if (causes == null) {
causes = new LinkedList<>();
}
causes.add(ex);
continue;
}
} else {
// 给定的显式参数 -> 参数长度必须完全匹配。
if (paramTypes.length != explicitArgs.length) {
continue;
}
// 构造函数没有参数的情况
argsHolder = new ArgumentsHolder(explicitArgs);
}
// 探测是否有不确定性的构造函数存在，例如不同构造函数的参数为父子关系
int typeDiffWeight = (mbd.isLenientConstructorResolution() ?
argsHolder.getTypeDifferenceWeight(paramTypes) : argsHolder.getAssignabilityWeight(paramTypes));
// 如果它代表着当前最接近的匹配则选择作为构造函数
if (typeDiffWeight < minTypeDiffWeight) {
constructorToUse = candidate;
argsHolderToUse = argsHolder;
argsToUse = argsHolder.arguments;
minTypeDiffWeight = typeDiffWeight;
ambiguousConstructors = null;
} else if (constructorToUse != null && typeDiffWeight == minTypeDiffWeight) {
if (ambiguousConstructors == null) {
ambiguousConstructors = new LinkedHashSet<>();
ambiguousConstructors.add(constructorToUse);
}
ambiguousConstructors.add(candidate);
}
}
if (constructorToUse == null) {
if (causes != null) {
UnsatisfiedDependencyException ex = causes.removeLast();
for (Exception cause : causes) {
this.beanFactory.onSuppressedException(cause);
}
}
} else if (ambiguousConstructors != null && !mbd.isLenientConstructorResolution()) {}
if (explicitArgs == null) {
// 将解析的构造函数加入缓存
argsHolderToUse.storeCache(mbd, constructorToUse);
}
}
final InstantiationStrategy strategy = beanFactory.getInstantiationStrategy();
Object beanInstance;
if (System.getSecurityManager() != null) {
final Constructor<?> ctorToUse = constructorToUse;
final Object[] argumentsToUse = argsToUse;
beanInstance = AccessController.doPrivileged(
new PrivilegedAction<Object>(){
public Object run(){
return strategy.instantiate(mbd, beanName, beanFactory, ctorToUse, argumentsToUse);
}
},beanFactory.getAccessControlContext());
} else {
beanInstance = strategy.instantiate(mbd, beanName, this.beanFactory, constructorToUse, argsToUse);
}
// 将构造的实例加入 BeanWrapper 中
bw.setBeanInstance(beanInstance);
return bw;
}
无参构造-instantiateBean
/**
* 使用其默认构造函数实例化给定的 bean.
* @param beanName bean的名称
* @param mbd bean 的 bean 定义
* @return 新实例的 BeanWrapper
*/
protected BeanWrapper instantiateBean(String beanName, RootBeanDefinition mbd) {
Object beanInstance;
final BeanFactory parent = this;
if (System.getSecurityManager() != null) {
beanInstance = AccessController.doPrivileged(
new PrivilegedAction<Object>(){
public Object run(){
return getInstantiationStrategy().instantiate(mbd, beanName, parent);
}
},getAccessControlContext());
} else {
beanInstance = getInstantiationStrategy().instantiate(mbd, beanName, parent);
}
BeanWrapper bw = new BeanWrapperImpl(beanInstance);
initBeanWrapper(bw);
return bw;
}
实例化策略-instantiate
@Override
public Object instantiate(RootBeanDefinition bd, @Nullable String beanName, BeanFactory owner) {
// 是否有 需要覆盖或者动态替换的方法，则使用cglib进行动态代理，因为在创建代理的同时将动态方法织入类中
// 如果没有覆盖，不要用 CGLIB 覆盖类。
if (!bd.hasMethodOverrides()) {
// 没有使用replace或者lookup的配置方法，那么反射
Constructor<?> constructorToUse;
synchronized (bd.constructorArgumentLock) {
constructorToUse = (Constructor<?>) bd.resolvedConstructorOrFactoryMethod;
if (constructorToUse == null) {
final Class<?> clazz = bd.getBeanClass();
if (System.getSecurityManager() != null) {
constructorToUse = AccessController.doPrivileged(
(PrivilegedExceptionAction<Constructor<?>>) clazz::getDeclaredConstructor);
} else {
constructorToUse = clazz.getDeclaredConstructor();
}
bd.resolvedConstructorOrFactoryMethod = constructorToUse;
}
}
return BeanUtils.instantiateClass(constructorToUse);
} else {
// 动态代理将replace或者lookup的配置方法所对应的逻辑的拦截增强器设置进去
// 这样保证在调用方法的时候会被相应的拦截器增强，返回值为包含拦截器的代理实例
// 必须生成CGLIB 子类。
return instantiateWithMethodInjection(bd, beanName, owner);
}
}
@Override
protected Object instantiateWithMethodInjection(RootBeanDefinition bd, @Nullable String beanName, BeanFactory owner,
@Nullable Constructor<?> ctor, @Nullable Object... args) {
// 必须生成CGLIB 子类...
return new CglibSubclassCreator(bd, owner).instantiate(ctor, args);
}
/**
* 创建动态生成的子类的新实例，实现所需的查找。
*
* @param ctor 要使用的构造函数。 如果这是 {@code null}，则使用无参数构造函数（无参数化或 Setter 注入）
* @param args 用于构造函数的参数。如果 {@code ctor} 参数为 {@code null}，则忽略。
* @return 动态生成的子类的新实例
*/
public Object instantiate(@Nullable Constructor<?> ctor, @Nullable Object... args) {
Class<?> subclass = createEnhancedSubclass(this.beanDefinition);
Object instance;
if (ctor == null) {
instance = BeanUtils.instantiateClass(subclass);
} else {
Constructor<?> enhancedSubclassConstructor = subclass.getConstructor(ctor.getParameterTypes());
instance = enhancedSubclassConstructor.newInstance(args);
}
// SPR-10785: 直接在实例上而不是在增强类中设置回调（通过增强器）以避免内存泄漏。
Factory factory = (Factory) instance;
factory.setCallbacks(new Callback[]{NoOp.INSTANCE,
new LookupOverrideMethodInterceptor(this.beanDefinition, this.owner),
new ReplaceOverrideMethodInterceptor(this.beanDefinition, this.owner)});
return instance;
}
createBeanInstance英文版
/**
* Create a new instance for the specified bean, using an appropriate instantiation strategy:
* factory method, constructor autowiring, or simple instantiation.
* @param beanName the name of the bean
* @param mbd the bean definition for the bean
* @param args explicit arguments to use for constructor or factory method invocation
* @return a BeanWrapper for the new instance
* @see #obtainFromSupplier
* @see #instantiateUsingFactoryMethod
* @see #autowireConstructor
* @see #instantiateBean
*/
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);
}
// No special handling: simply use no-arg constructor.
return instantiateBean(beanName, mbd);
}
autowireConstructor英文版
/**
* "autowire constructor" (with constructor arguments by type) behavior.
* Also applied if explicit constructor argument values are specified,
* matching all remaining arguments with beans from the bean factory.
* <p>This corresponds to constructor injection: In this mode, a Spring
* bean factory is able to host components that expect constructor-based
* dependency resolution.
* @param beanName the name of the bean
* @param mbd the merged bean definition for the bean
* @param chosenCtors chosen candidate constructors (or {@code null} if none)
* @param explicitArgs argument values passed in programmatically via the getBean method,
* or {@code null} if none (-> use constructor argument values from bean definition)
* @return a BeanWrapper for the new instance
*/
public BeanWrapper autowireConstructor(String beanName, RootBeanDefinition mbd,
@Nullable Constructor<?>[] chosenCtors, @Nullable Object[] explicitArgs) {
BeanWrapperImpl bw = new BeanWrapperImpl();
this.beanFactory.initBeanWrapper(bw);
Constructor<?> constructorToUse = null;
ArgumentsHolder argsHolderToUse = null;
Object[] argsToUse = null;
if (explicitArgs != null) {
argsToUse = explicitArgs;
}
else {
Object[] argsToResolve = null;
synchronized (mbd.constructorArgumentLock) {
constructorToUse = (Constructor<?>) mbd.resolvedConstructorOrFactoryMethod;
if (constructorToUse != null && mbd.constructorArgumentsResolved) {
// Found a cached constructor...
argsToUse = mbd.resolvedConstructorArguments;
if (argsToUse == null) {
argsToResolve = mbd.preparedConstructorArguments;
}
}
}
if (argsToResolve != null) {
argsToUse = resolvePreparedArguments(beanName, mbd, bw, constructorToUse, argsToResolve);
}
}
if (constructorToUse == null) {
// Need to resolve the constructor.
boolean autowiring = (chosenCtors != null ||
mbd.getResolvedAutowireMode() == AutowireCapableBeanFactory.AUTOWIRE_CONSTRUCTOR);
ConstructorArgumentValues resolvedValues = null;
int minNrOfArgs;
if (explicitArgs != null) {
minNrOfArgs = explicitArgs.length;
}
else {
ConstructorArgumentValues cargs = mbd.getConstructorArgumentValues();
resolvedValues = new ConstructorArgumentValues();
minNrOfArgs = resolveConstructorArguments(beanName, mbd, bw, cargs, resolvedValues);
}
// Take specified constructors, if any.
Constructor<?>[] candidates = chosenCtors;
if (candidates == null) {
Class<?> beanClass = mbd.getBeanClass();
try {
candidates = (mbd.isNonPublicAccessAllowed() ?
beanClass.getDeclaredConstructors() : beanClass.getConstructors());
}
catch (Throwable ex) {
throw new BeanCreationException(mbd.getResourceDescription(), beanName,
"Resolution of declared constructors on bean Class [" + beanClass.getName() +
"] from ClassLoader [" + beanClass.getClassLoader() + "] failed", ex);
}
}
AutowireUtils.sortConstructors(candidates);
int minTypeDiffWeight = Integer.MAX_VALUE;
Set<Constructor<?>> ambiguousConstructors = null;
LinkedList<UnsatisfiedDependencyException> causes = null;
for (Constructor<?> candidate : candidates) {
Class<?>[] paramTypes = candidate.getParameterTypes();
if (constructorToUse != null && argsToUse.length > paramTypes.length) {
// Already found greedy constructor that can be satisfied ->
// do not look any further, there are only less greedy constructors left.
break;
}
if (paramTypes.length < minNrOfArgs) {
continue;
}
ArgumentsHolder argsHolder;
if (resolvedValues != null) {
try {
String[] paramNames = ConstructorPropertiesChecker.evaluate(candidate, paramTypes.length);
if (paramNames == null) {
ParameterNameDiscoverer pnd = this.beanFactory.getParameterNameDiscoverer();
if (pnd != null) {
paramNames = pnd.getParameterNames(candidate);
}
}
argsHolder = createArgumentArray(beanName, mbd, resolvedValues, bw, paramTypes, paramNames,
getUserDeclaredConstructor(candidate), autowiring);
}
catch (UnsatisfiedDependencyException ex) {
if (logger.isTraceEnabled()) {
logger.trace("Ignoring constructor [" + candidate + "] of bean '" + beanName + "': " + ex);
}
// Swallow and try next constructor.
if (causes == null) {
causes = new LinkedList<>();
}
causes.add(ex);
continue;
}
}
else {
// Explicit arguments given -> arguments length must match exactly.
if (paramTypes.length != explicitArgs.length) {
continue;
}
argsHolder = new ArgumentsHolder(explicitArgs);
}
int typeDiffWeight = (mbd.isLenientConstructorResolution() ?
argsHolder.getTypeDifferenceWeight(paramTypes) : argsHolder.getAssignabilityWeight(paramTypes));
// Choose this constructor if it represents the closest match.
if (typeDiffWeight < minTypeDiffWeight) {
constructorToUse = candidate;
argsHolderToUse = argsHolder;
argsToUse = argsHolder.arguments;
minTypeDiffWeight = typeDiffWeight;
ambiguousConstructors = null;
}
else if (constructorToUse != null && typeDiffWeight == minTypeDiffWeight) {
if (ambiguousConstructors == null) {
ambiguousConstructors = new LinkedHashSet<>();
ambiguousConstructors.add(constructorToUse);
}
ambiguousConstructors.add(candidate);
}
}
if (constructorToUse == null) {
if (causes != null) {
UnsatisfiedDependencyException ex = causes.removeLast();
for (Exception cause : causes) {
this.beanFactory.onSuppressedException(cause);
}
throw ex;
}
throw new BeanCreationException(mbd.getResourceDescription(), beanName,
"Could not resolve matching constructor " +
"(hint: specify index/type/name arguments for simple parameters to avoid type ambiguities)");
}
else if (ambiguousConstructors != null && !mbd.isLenientConstructorResolution()) {
throw new BeanCreationException(mbd.getResourceDescription(), beanName,
"Ambiguous constructor matches found in bean '" + beanName + "' " +
"(hint: specify index/type/name arguments for simple parameters to avoid type ambiguities): " +
ambiguousConstructors);
}
if (explicitArgs == null) {
argsHolderToUse.storeCache(mbd, constructorToUse);
}
}
try {
final InstantiationStrategy strategy = beanFactory.getInstantiationStrategy();
Object beanInstance;
if (System.getSecurityManager() != null) {
final Constructor<?> ctorToUse = constructorToUse;
final Object[] argumentsToUse = argsToUse;
beanInstance = AccessController.doPrivileged((PrivilegedAction<Object>) () ->
strategy.instantiate(mbd, beanName, beanFactory, ctorToUse, argumentsToUse),
beanFactory.getAccessControlContext());
}
else {
beanInstance = strategy.instantiate(mbd, beanName, this.beanFactory, constructorToUse, argsToUse);
}
bw.setBeanInstance(beanInstance);
return bw;
}
catch (Throwable ex) {
throw new BeanCreationException(mbd.getResourceDescription(), beanName,
"Bean instantiation via constructor failed", ex);
}
}
instantiateBean英文版
/**
* Instantiate the given bean using its default constructor.
* @param beanName the name of the bean
* @param mbd the bean definition for the bean
* @return a BeanWrapper for the new instance
*/
protected BeanWrapper instantiateBean(String beanName, RootBeanDefinition mbd) {
try {
Object beanInstance;
if (System.getSecurityManager() != null) {
beanInstance = AccessController.doPrivileged(
(PrivilegedAction<Object>) () -> getInstantiationStrategy().instantiate(mbd, beanName, this),
getAccessControlContext());
}
else {
beanInstance = getInstantiationStrategy().instantiate(mbd, beanName, this);
}
BeanWrapper bw = new BeanWrapperImpl(beanInstance);
initBeanWrapper(bw);
return bw;
}
catch (Throwable ex) {
throw new BeanCreationException(
mbd.getResourceDescription(), beanName, "Instantiation of bean failed", ex);
}
}
instantiate英文版
@Override
public Object instantiate(RootBeanDefinition bd, @Nullable String beanName, BeanFactory owner) {
// Don't override the class with CGLIB if no overrides.
if (!bd.hasMethodOverrides()) {
Constructor<?> constructorToUse;
synchronized (bd.constructorArgumentLock) {
constructorToUse = (Constructor<?>) bd.resolvedConstructorOrFactoryMethod;
if (constructorToUse == null) {
final Class<?> clazz = bd.getBeanClass();
if (clazz.isInterface()) {
throw new BeanInstantiationException(clazz, "Specified class is an interface");
}
try {
if (System.getSecurityManager() != null) {
constructorToUse = AccessController.doPrivileged(
(PrivilegedExceptionAction<Constructor<?>>) clazz::getDeclaredConstructor);
}
else {
constructorToUse = clazz.getDeclaredConstructor();
}
bd.resolvedConstructorOrFactoryMethod = constructorToUse;
}
catch (Throwable ex) {
throw new BeanInstantiationException(clazz, "No default constructor found", ex);
}
}
}
return BeanUtils.instantiateClass(constructorToUse);
}
else {
// Must generate CGLIB subclass.
return instantiateWithMethodInjection(bd, beanName, owner);
}
}
@Override
protected Object instantiateWithMethodInjection(RootBeanDefinition bd, @Nullable String beanName, BeanFactory owner) {
return instantiateWithMethodInjection(bd, beanName, owner, null);
}
@Override
protected Object instantiateWithMethodInjection(RootBeanDefinition bd, @Nullable String beanName, BeanFactory owner,
@Nullable Constructor<?> ctor, @Nullable Object... args) {
// Must generate CGLIB subclass...
return new CglibSubclassCreator(bd, owner).instantiate(ctor, args);
}
/**
* Create a new instance of a dynamically generated subclass implementing the
* required lookups.
* @param ctor constructor to use. If this is {@code null}, use the
* no-arg constructor (no parameterization, or Setter Injection)
* @param args arguments to use for the constructor.
* Ignored if the {@code ctor} parameter is {@code null}.
* @return new instance of the dynamically generated subclass
*/
public Object instantiate(@Nullable Constructor<?> ctor, @Nullable Object... args) {
Class<?> subclass = createEnhancedSubclass(this.beanDefinition);
Object instance;
if (ctor == null) {
instance = BeanUtils.instantiateClass(subclass);
}
else {
try {
Constructor<?> enhancedSubclassConstructor = subclass.getConstructor(ctor.getParameterTypes());
instance = enhancedSubclassConstructor.newInstance(args);
}
catch (Exception ex) {
throw new BeanInstantiationException(this.beanDefinition.getBeanClass(),
"Failed to invoke constructor for CGLIB enhanced subclass [" + subclass.getName() + "]", ex);
}
}
// SPR-10785: set callbacks directly on the instance instead of in the
// enhanced class (via the Enhancer) in order to avoid memory leaks.
Factory factory = (Factory) instance;
factory.setCallbacks(new Callback[] {NoOp.INSTANCE,
new LookupOverrideMethodInterceptor(this.beanDefinition, this.owner),
new ReplaceOverrideMethodInterceptor(this.beanDefinition, this.owner)});
return instance;
}
