源码分析:doCreateBean

spring的ioc创建bean的最核心代码 我们来看看他具体做了啥 怎么做

整体的逻辑

protected Object doCreateBean(final String beanName, final RootBeanDefinition mbd, final @Nullable Object[] args)
            throws BeanCreationException {

    BeanWrapper ,包含了真正的bean对象和bean的class,以及PropertyDescriptor集合
        BeanWrapper instanceWrapper = null;
单例的情况下尝试从factoryBeanInstanceCache获取 instanceWrapper 
        if (mbd.isSingleton()) {
            instanceWrapper = this.factoryBeanInstanceCache.remove(beanName);
        }
如果没有则需要自己创建
        if (instanceWrapper == null) {
            instanceWrapper = createBeanInstance(beanName, mbd, args);
        }
        final Object bean = instanceWrapper.getWrappedInstance();
        Class beanType = instanceWrapper.getWrappedClass();
如果不是NullBean,则将resolvedTargetType 属性设置为当前的WrappedClass
        if (beanType != NullBean.class) {
            mbd.resolvedTargetType = beanType;
        }

    这边主要是寻找几个meta,@PostConstruct,@Autowire,@Value,@Resource,@PreDestory等
        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;
            }
        }

如果当前bean是单例,且支持循环依赖,且当前bean正在创建,通过往singletonFactories添加一个objectFactory,
这样后期如果有其他bean依赖该bean 可以从singletonFactories获取到bean,getEarlyBeanReference可以对返回的bean进行修改,这边目前除了可能会返回动态代理对象 其他的都是直接返回bean
        boolean earlySingletonExposure = (mbd.isSingleton() && this.allowCircularReferences &&
                isSingletonCurrentlyInCreation(beanName));
        if (earlySingletonExposure) {
            if (logger.isDebugEnabled()) {
                logger.debug("Eagerly caching bean '" + beanName +
                        "' to allow for resolving potential circular references");
            }
            addSingletonFactory(beanName, () -> getEarlyBeanReference(beanName, mbd, bean));
        }

        
        Object exposedObject = bean;
        try {
填充bean的属性
            populateBean(beanName, mbd, instanceWrapper);
初始化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);
            }
        }
如果earlySingletonExposure,尝试从缓存获取该bean(一般存放在singletonFactories对象通过调用getObject 把对象存入earlySingletonObjects),分别从singletonObjects和earlySingletonObjects获取对象
        if (earlySingletonExposure) {
            Object earlySingletonReference = getSingleton(beanName, false);
如果获取到对象了
            if (earlySingletonReference != null) {
当exposedObject (初始化之后的bean等于原始的bean,说明不是proxy),则把缓存中的bean赋值给exposedObject 
                if (exposedObject == bean) {
                    exposedObject = earlySingletonReference;
                }
检测该bean的dependon的bean是否都已经初始化好了
                else if (!this.allowRawInjectionDespiteWrapping && hasDependentBean(beanName)) {
                    String[] dependentBeans = getDependentBeans(beanName);
                    Set 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.");
                    }
                }
            }
        }

        
        try {
注册DisposableBean
            registerDisposableBeanIfNecessary(beanName, bean, mbd);
        }
        catch (BeanDefinitionValidationException ex) {
            throw new BeanCreationException(
                    mbd.getResourceDescription(), beanName, "Invalid destruction signature", ex);
        }

        return exposedObject;
    }

createBeanInstance的源码分析

protected BeanWrapper createBeanInstance(String beanName, RootBeanDefinition mbd, @Nullable Object[] args) {
    获取beanclass
        Class beanClass = resolveBeanClass(mbd, beanName);
如果beanclass为空,且beanclass不是public 且没有权限访问构造函数和方法则抛出异常
        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类似于factoryBean,然后从Supplier.get()的bean,并把bean包装成BeanWrapper,然后初始化BeanWrapper
        Supplier instanceSupplier = mbd.getInstanceSupplier();
        if (instanceSupplier != null) {
            return obtainFromSupplier(instanceSupplier, beanName);
        }
尝试从factoryMethod获取instanceSupplier
        if (mbd.getFactoryMethodName() != null)  {
            return instantiateUsingFactoryMethod(beanName, mbd, args);
        }

        这边是相当于检测是否曾经创建过这个bean,如果是查看下具体采用哪个方法
        boolean resolved = false;
        boolean autowireNecessary = false;
        if (args == null) {
            synchronized (mbd.constructorArgumentLock) {
说明曾经解析过构造函数或者factoryMethod
                if (mbd.resolvedConstructorOrFactoryMethod != null) {
                    resolved = true;
如果autowireNecessary为true说明是采用构造函数注入
                    autowireNecessary = mbd.constructorArgumentsResolved;
                }
            }
        }
如果已经解析过了则按照逻辑选择
        if (resolved) {
            if (autowireNecessary) {
                return autowireConstructor(beanName, mbd, null, null);
            }
            else {
                return instantiateBean(beanName, mbd);
            }
        }

    说明是第一次创建该bean   根据SmartInstantiationAwareBeanPostProcessor获取构造函数,目前看基本上都是空的实现,除了AutowiredAnnotationBeanPostProcessor
        Constructor[] ctors = determineConstructorsFromBeanPostProcessors(beanClass, beanName);
        if (ctors != null ||
                mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_CONSTRUCTOR ||
                mbd.hasConstructorArgumentValues() || !ObjectUtils.isEmpty(args))  {
开始生成实例
            return autowireConstructor(beanName, mbd, ctors, args);
        }

采用普通的方式生成实例
        return instantiateBean(beanName, mbd);
    }
AutowiredAnnotationBeanPostProcessor的determineCandidateConstructors

寻找被@Autowired的构造函数,如果没有就返回null


我们的lookup就是在这边通过反射发现的(其他的xml形式的replace-method和lookup在BeanDefinitionParserDelegate中)
        if (!this.lookupMethodsChecked.contains(beanName)) {
            try {
                ReflectionUtils.doWithMethods(beanClass, method -> {
                    Lookup lookup = method.getAnnotation(Lookup.class);
                    if (lookup != null) {
                        Assert.state(beanFactory != null, "No BeanFactory available");
                        LookupOverride override = new LookupOverride(method, lookup.value());
                        try {
                            RootBeanDefinition mbd = (RootBeanDefinition) beanFactory.getMergedBeanDefinition(beanName);
                            mbd.getMethodOverrides().addOverride(override);
                        }
                        catch (NoSuchBeanDefinitionException ex) {
                            throw new BeanCreationException(beanName,
                                "Cannot apply @Lookup to beans without corresponding bean definition");
                        }
                    }
                });
            }
            catch (IllegalStateException ex) {
                throw new BeanCreationException(beanName, "Lookup method resolution failed", ex);
            }
            this.lookupMethodsChecked.add(beanName);
        }

    检测缓存中是否已经存在对应的构造函数
        Constructor[] candidateConstructors = this.candidateConstructorsCache.get(beanClass);
        if (candidateConstructors == null) {
            双重检测
            synchronized (this.candidateConstructorsCache) {
                candidateConstructors = this.candidateConstructorsCache.get(beanClass);
                if (candidateConstructors == null) {
                    Constructor[] rawCandidates;
                    try {
获取声明的构造函数
                        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> candidates = new ArrayList<>(rawCandidates.length);
                    Constructor requiredConstructor = null;
                    Constructor defaultConstructor = null;
这个只对Kotlin有用 对于java 一般默认的返回null
                    Constructor primaryConstructor = BeanUtils.findPrimaryConstructor(beanClass);
                    int nonSyntheticConstructors = 0;
                    for (Constructor candidate : rawCandidates) {
如果不是合成,则nonSyntheticConstructors加1
                        if (!candidate.isSynthetic()) {
                            nonSyntheticConstructors++;
                        }
                        else if (primaryConstructor != null) {
                            continue;
                        }
                        AnnotationAttributes ann = 
寻找构造上是否存在@Autowired,@Value,@Inject,如果存在就返回required=true,一个bean的构造函数如果超过一个@Autowired就抛出异常
findAutowiredAnnotation(candidate);
如果没有
                        if (ann == null) {
一般都是返回class本身,如果是cglib就返回原始的类
                            Class userClass = ClassUtils.getUserClass(beanClass);
                            if (userClass != beanClass) {
                                try {
获取带有参数的构造函数
                                    Constructor superCtor =
                                            userClass.getDeclaredConstructor(candidate.getParameterTypes());
继续寻找是否携带了上面三个注解
                                    ann = findAutowiredAnnotation(superCtor);
                                }
                                catch (NoSuchMethodException ex) {
                                    // Simply proceed, no equivalent superclass constructor found...
                                }
                            }
                        }
ann!=null 代表找到了
                        if (ann != null) {
如果requiredConstructor  不为null 说明重复定义
                            if (requiredConstructor != null) {
                                throw new BeanCreationException(beanName,
                                        "Invalid autowire-marked constructor: " + candidate +
                                        ". Found constructor with 'required' Autowired annotation already: " +
                                        requiredConstructor);
                            }
这边只是确认下required返回的是true还是false
                            boolean required = determineRequiredStatus(ann);
如果required是true
                            if (required) {
但是candidates不为空说明重复了
                                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.isWarnEnabled()) {
                                logger.warn("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);
initBeanWrapper
初始BeanWrapperImpl,设置ConversionService
(可以查看每个类型是否可以转换成其他类型,并提供转换的方法)和注册
一些列的ResourceEditor到bw,比如    doRegisterEditor(registry, 
Resource.class, baseEditor);如果遇到Resource类型的使用baseEditor,进
行编辑。
protected void initBeanWrapper(BeanWrapper bw) {
        bw.setConversionService(getConversionService());
        registerCustomEditors(bw);
    }

    protected void registerCustomEditors(PropertyEditorRegistry registry) {
        PropertyEditorRegistrySupport registrySupport =
                (registry instanceof PropertyEditorRegistrySupport ? (PropertyEditorRegistrySupport) registry : null);
        if (registrySupport != null) {
            registrySupport.useConfigValueEditors();
        }
        if (!this.propertyEditorRegistrars.isEmpty()) {
            for (PropertyEditorRegistrar registrar : this.propertyEditorRegistrars) {
                try {
                    registrar.registerCustomEditors(registry);
                }
                catch (BeanCreationException ex) {
                    Throwable rootCause = ex.getMostSpecificCause();
                    if (rootCause instanceof BeanCurrentlyInCreationException) {
                        BeanCreationException bce = (BeanCreationException) rootCause;
                        String bceBeanName = bce.getBeanName();
                        if (bceBeanName != null && isCurrentlyInCreation(bceBeanName)) {
                            if (logger.isDebugEnabled()) {
                                logger.debug("PropertyEditorRegistrar [" + registrar.getClass().getName() +
                                        "] failed because it tried to obtain currently created bean '" +
                                        ex.getBeanName() + "': " + ex.getMessage());
                            }
                            onSuppressedException(ex);
                            continue;
                        }
                    }
                    throw ex;
                }
            }
        }
如果存在用户自定义的类型转换 也设置
        if (!this.customEditors.isEmpty()) {
            this.customEditors.forEach((requiredType, editorClass) ->
                    registry.registerCustomEditor(requiredType, BeanUtils.instantiateClass(editorClass)));
        }
    }
MergedBeanDefinitionPostProcessors---AutowiredAnnotationBeanPostProcessor
public void postProcessMergedBeanDefinition(RootBeanDefinition beanDefinition, Class beanType, String beanName) {
获取@Autowired注解的属性
        InjectionMetadata metadata = findAutowiringMetadata(beanName, beanType, null);
校验
        metadata.checkConfigMembers(beanDefinition);
    }


private InjectionMetadata findAutowiringMetadata(String beanName, Class clazz, @Nullable PropertyValues pvs) {
    获取cacheKey
        String cacheKey = (StringUtils.hasLength(beanName) ? beanName : clazz.getName());

        InjectionMetadata metadata = this.injectionMetadataCache.get(cacheKey);
如果metadata为空,或者clazz!=metadata.targetClass则说明没有缓存无效,重新buildAutowiringMetadata,然后把结果缓存起来
        if (InjectionMetadata.needsRefresh(metadata, clazz)) {
            synchronized (this.injectionMetadataCache) {
                metadata = this.injectionMetadataCache.get(cacheKey);
                if (InjectionMetadata.needsRefresh(metadata, clazz)) {
                    if (metadata != null) {
                        metadata.clear(pvs);
                    }
分别从class的field和method获取@Autowired,并放入缓存(会迭代查询其父类class)
                    metadata = buildAutowiringMetadata(clazz);
                    this.injectionMetadataCache.put(cacheKey, metadata);
                }
            }
        }
        return metadata;
    }





public void checkConfigMembers(RootBeanDefinition beanDefinition) {
        Set checkedElements = new LinkedHashSet<>(this.injectedElements.size());
        for (InjectedElement element : this.injectedElements) {
把method或者field放入externallyManagedConfigMembers缓存中
            Member member = element.getMember();
            if (!beanDefinition.isExternallyManagedConfigMember(member)) {
                beanDefinition.registerExternallyManagedConfigMember(member);
                checkedElements.add(element);
                if (logger.isDebugEnabled()) {
                    logger.debug("Registered injected element on class [" + this.targetClass.getName() + "]: " + element);
                }
            }
        }
        this.checkedElements = checkedElements;
    }


填充属性-populateBean--先对于unsatisfiedNonSimpleProperties(未在xml配置该property 该property是一个特殊的对象(普通的javabean的类))属性进行处理,在对一些注解注入的属性处理,最终对自动注入的属性(即包含set方法的)属性进行处理
protected void populateBean(String beanName, RootBeanDefinition mbd, @Nullable BeanWrapper bw) {
如果实力为空但是还有属性,抛出异常
        if (bw == null) {
            if (mbd.hasPropertyValues()) {
                throw new BeanCreationException(
                        mbd.getResourceDescription(), beanName, "Cannot apply property values to null instance");
            }
            else {
        直接返回
                return;
            }
        }

    
        boolean continueWithPropertyPopulation = true;
这边主要是根据InstantiationAwareBeanPostProcessor 判断是否继续给该bean配置属性
        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;
        }
设置PropertyValues 
        PropertyValues pvs = (mbd.hasPropertyValues() ? mbd.getPropertyValues() : null);
如果该bean是支持按照名字或者类型自动注入的,
        if (mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_NAME ||
                mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_TYPE) {
深度拷贝PropertyValues,当然对于对象来说只能公用一个
            MutablePropertyValues newPvs = new MutablePropertyValues(pvs);

    按照名称开始注入(这边不是真正的注入,只是寻找可注入的bean)
必须有set方法
必须不能是忽略的类型或者接口
spring配置的properties中没有改属性
该属性不能是 a primitive, an enum, a String or other CharSequence, a Number, a Date,
     * a URI, a URL, a Locale or a Class.
     其中primitive( boolean, byte,
     * char, short, int, long, float, or double)或者其包装类
     如果class是array 其元素也不能是上述属性
     -------
     
     也就是说自动注入的时候 如果不显示的配置 对于非对象的类型是不会注入的,但是对于对象是会主动去寻找的
            if (mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_NAME) {
                autowireByName(beanName, mbd, bw, newPvs);
            }

按照类型开始注入(这边不是真正的注入,只是寻找可注入的bean)
必须有set方法
必须不能是忽略的类型或者接口
spring配置的properties中没有改属性
该属性不能是 a primitive, an enum, a String or other CharSequence, a Number, a Date,
     * a URI, a URL, a Locale or a Class.
     其中primitive( boolean, byte,
     * char, short, int, long, float, or double)或者其包装类
     如果class是array 其元素也不能是上述属性
     -------
     
     也就是说自动注入的时候 如果不显示的配置 对于非对象的类型是不会注入的,但是对于对象是会主动去寻找的
            if (mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_TYPE) {
                autowireByType(beanName, mbd, bw, newPvs);
            }

            pvs = newPvs;
        }

        boolean hasInstAwareBpps = hasInstantiationAwareBeanPostProcessors();
        boolean needsDepCheck = (mbd.getDependencyCheck() != RootBeanDefinition.DEPENDENCY_CHECK_NONE);
如果存在InstantiationAwareBeanPostProcessors或者有依赖检测
        if (hasInstAwareBpps || needsDepCheck) {
            if (pvs == null) {
                pvs = mbd.getPropertyValues();
            }
获得一组PropertyDescriptor,filterPropertyDescriptorsForDependencyCheck
---获取该bean下面的所有属性和方法
---删除如果是cglib的本身的属性和方法
---删除如果是ignoredDependencyTypes
---删除如果是set方法且需要忽略的(即实现了xxawared接口的)也需要删除
---最终保留的属性可以自动注入
            PropertyDescriptor[] filteredPds = filterPropertyDescriptorsForDependencyCheck(bw, mbd.allowCaching);
            if (hasInstAwareBpps) {
                for (BeanPostProcessor bp : getBeanPostProcessors()) {
                    if (bp instanceof InstantiationAwareBeanPostProcessor) {
                        InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp;
对@Autowired,@Resource等属性的注入
                        pvs = ibp.postProcessPropertyValues(pvs, filteredPds, bw.getWrappedInstance(), beanName);
                        if (pvs == null) {
                            return;
                        }
                    }
                }
            }
依赖检测
            if (needsDepCheck) {
                checkDependencies(beanName, mbd, filteredPds, pvs);
            }
        }
对自动注入的时候 set方法的注入
        if (pvs != null) {
            applyPropertyValues(beanName, mbd, bw, pvs);
        }
    }

初始化bean-initializeBean

第一种:通过@PostConstruct 和 @PreDestroy 方法 实现初始化和销毁bean之前进行的操作

第二种是:通过 在xml中定义init-method 和 destory-method方法

第三种是: 通过bean实现InitializingBean和 DisposableBean接口
三种销毁方式都是把bean转换成DisposableBean

protected Object initializeBean(final String beanName, final Object bean, @Nullable RootBeanDefinition mbd) {
首先调用回调方法xxxaware
        if (System.getSecurityManager() != null) {
            AccessController.doPrivileged((PrivilegedAction) () -> {
                invokeAwareMethods(beanName, bean);
                return null;
            }, getAccessControlContext());
        }
        else {
            invokeAwareMethods(beanName, bean);
        }
调用spring的扩展点 在初始化之前调用
        Object wrappedBean = bean;
        if (mbd == null || !mbd.isSynthetic()) {
            wrappedBean = applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName);
        }

        try {
先调用InitializingBean的afterPropertiesSet,在调用我们定义的init方法
            invokeInitMethods(beanName, wrappedBean, mbd);
        }
        catch (Throwable ex) {
            throw new BeanCreationException(
                    (mbd != null ? mbd.getResourceDescription() : null),
                    beanName, "Invocation of init method failed", ex);
        }
调用spring的扩展点 在初始化之后调用,注意这边就是生成我们配置的动态代理对象的关键代码
        if (mbd == null || !mbd.isSynthetic()) {
            wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);
        }

        return wrappedBean;
    }
 
 
注册registerDisposableBeanIfNecessary
protected void registerDisposableBeanIfNecessary(String beanName, Object bean, RootBeanDefinition mbd) {
        AccessControlContext acc = (System.getSecurityManager() != null ? getAccessControlContext() : null);
只有非原型且是DisposableBean,或者有destroy method  或者注册了 DestructionAwareBeanPostProcessors.
最终在缓存中存放beanName和DisposableBean的映射关系,然后注册钩子的时候调用
        if (!mbd.isPrototype() && requiresDestruction(bean, mbd)) {
针对单例或者scope注册
            if (mbd.isSingleton()) {
    最终在缓存中存放beanName和DisposableBean的映射关系,然后注册钩子的时候调用
                registerDisposableBean(beanName,
                        new DisposableBeanAdapter(bean, beanName, mbd, getBeanPostProcessors(), acc));
            }
            else {
                // A bean with a custom scope...
                Scope scope = this.scopes.get(mbd.getScope());
                if (scope == null) {
                    throw new IllegalStateException("No Scope registered for scope name '" + mbd.getScope() + "'");
                }
注册了一个回调,根据scope的类型(比如是一个线程,一个request,servlet,事务)当这几种结束的时候回调这个DisposableBeanAdapter的destory方法
                scope.registerDestructionCallback(beanName,
                        new DisposableBeanAdapter(bean, beanName, mbd, getBeanPostProcessors(), acc));
            }
        }
    }

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