Spring专题之Bean初始化源码分析（2）

时间 2019-12-04

原文原文链接

前言

这篇是Spring专题Bean初始化的第二篇，主要对bean初始化具体过程的源码分析。上篇博客Spring专题之Bean初始化源码分析（1）中咱们对Spring如何开始初始化bean以及bena初始化的整体过程有了大体的了解，接下来就继续上篇博客的结尾处开始来分析初始化bean的具体过程。segmentfault

Bean初始化

上篇博客中咱们知道了Spring在经过判断bean定义是不是单例bean，是不是原型bena以后，最后都是调用了createBean方法去建立bean的，因此咱们进入该方法分析具体初始化过程。进入方法后发现是该方法是AbstractBeanFactory的一个抽象方法，真正地调用是在子类AbstractAutowireCapableBeanFactory中重写了。源码以下：数组

//建立Bean实例对象
    protected Object createBean(String beanName, RootBeanDefinition mbd, @Nullable Object[] args)
            throws BeanCreationException {

        if (logger.isDebugEnabled()) {
            logger.debug("Creating instance of bean '" + beanName + "'");
        }
        RootBeanDefinition mbdToUse = mbd;

        //判断须要建立的Bean是否能够实例化，便是否能够经过当前的类加载器加载
        Class<?> resolvedClass = resolveBeanClass(mbd, beanName);
        if (resolvedClass != null && !mbd.hasBeanClass() && mbd.getBeanClassName() != null) {
            mbdToUse = new RootBeanDefinition(mbd);
            mbdToUse.setBeanClass(resolvedClass);
        }

        //校验和准备Bean中的方法覆盖
        try {
            mbdToUse.prepareMethodOverrides();
        }
        catch (BeanDefinitionValidationException ex) {
            throw new BeanDefinitionStoreException(mbdToUse.getResourceDescription(),
                    beanName, "Validation of method overrides failed", ex);
        }

        try {
            //若是Bean配置了初始化前和初始化后的处理器，则试图返回一个须要建立Bean的代理对象
            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 {
            //建立Bean的入口
            Object beanInstance = doCreateBean(beanName, mbdToUse, args);
            if (logger.isDebugEnabled()) {
                logger.debug("Finished creating instance of bean '" + beanName + "'");
            }
            return beanInstance;
        }
        catch (BeanCreationException ex) {
            throw ex;
        }
        catch (ImplicitlyAppearedSingletonException ex) {
            throw ex;
        }
        catch (Throwable ex) {
            throw new BeanCreationException(
                    mbdToUse.getResourceDescription(), beanName, "Unexpected exception during bean creation", ex);
        }
    }

这里咱们有两个地方须要了解的，第一个是resolveBeforeInstantiation方法，第二个是doCreateBean方法。以后咱们重点分析doCreateBean方法，这里的resolveBeforeInstantiation方法主要是针对Bean若是配置了初始化前和初始化后的处理器，会试图返回一个须要建立Bean的代理对象。那么如今咱们开始进入doCreateBean方法，源码以下：缓存

//真正建立Bean的方法
    protected Object doCreateBean(final String beanName, final RootBeanDefinition mbd, final @Nullable Object[] args)
            throws BeanCreationException {

        //封装被建立的Bean对象
        BeanWrapper instanceWrapper = null;
        if (mbd.isSingleton()) {
            instanceWrapper = this.factoryBeanInstanceCache.remove(beanName);
        }
        if (instanceWrapper == null) {
            instanceWrapper = createBeanInstance(beanName, mbd, args);
        }
        final Object bean = instanceWrapper.getWrappedInstance();
        //获取实例化对象的类型
        Class<?> beanType = instanceWrapper.getWrappedClass();
        if (beanType != NullBean.class) {
            mbd.resolvedTargetType = beanType;
        }

        //调用PostProcessor后置处理器
        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;
            }
        }

        //向容器中缓存单例模式的Bean对象，以防循环引用
        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");
            }
            //这里是一个匿名内部类，为了防止循环引用，尽早持有对象的引用
            addSingletonFactory(beanName, () -> getEarlyBeanReference(beanName, mbd, bean));
        }

        //Bean对象的初始化，依赖注入在此触发
        //这个exposedObject在初始化完成以后返回做为依赖注入完成后的Bean
        Object exposedObject = bean;
        try {
            //将Bean实例对象封装，而且Bean定义中配置的属性值赋值给实例对象
            populateBean(beanName, mbd, instanceWrapper);
            //初始化Bean对象
            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) {
            //获取指定名称的已注册的单例模式Bean对象
            Object earlySingletonReference = getSingleton(beanName, false);
            if (earlySingletonReference != null) {
                //根据名称获取的已注册的Bean和正在实例化的Bean是同一个
                if (exposedObject == bean) {
                    //当前实例化的Bean初始化完成
                    exposedObject = earlySingletonReference;
                }
                //当前Bean依赖其余Bean，而且当发生循环引用时不容许新建立实例对象
                else if (!this.allowRawInjectionDespiteWrapping && hasDependentBean(beanName)) {
                    String[] dependentBeans = getDependentBeans(beanName);
                    Set<String> actualDependentBeans = new LinkedHashSet<>(dependentBeans.length);
                    //获取当前Bean所依赖的其余Bean
                    for (String dependentBean : dependentBeans) {
                        //对依赖Bean进行类型检查
                        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.
        //注册完成依赖注入的Bean
        try {
            registerDisposableBeanIfNecessary(beanName, bean, mbd);
        }
        catch (BeanDefinitionValidationException ex) {
            throw new BeanCreationException(
                    mbd.getResourceDescription(), beanName, "Invalid destruction signature", ex);
        }

        return exposedObject;
    }

这里有三个方法咱们须要注意，第一个createBeanInstance方法，这是bean实例化的第一步，第二个是populateBean方法，这是bean依赖注入的地方，第三个是initializeBean，这是初始化bean的地方。安全

首先咱们先看createBeanInstance方法，源码以下：app

//建立Bean的实例对象
    protected BeanWrapper createBeanInstance(String beanName, RootBeanDefinition mbd, @Nullable Object[] args) {
        // Make sure bean class is actually resolved at this point.
        //检查确认Bean是可实例化的
        Class<?> beanClass = resolveBeanClass(mbd, beanName);

        //使用工厂方法对Bean进行实例化
        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)  {
            //调用工厂方法实例化
            return instantiateUsingFactoryMethod(beanName, mbd, args);
        }

        // Shortcut when re-creating the same bean...
        //使用容器的自动装配方法进行实例化
        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) {
                //配置了自动装配属性，使用容器的自动装配实例化
                //容器的自动装配是根据参数类型匹配Bean的构造方法
                return autowireConstructor(beanName, mbd, null, null);
            }
            else {
                //使用默认的无参构造方法实例化
                return instantiateBean(beanName, mbd);
            }
        }

        // Need to determine the constructor...
        //使用Bean的构造方法进行实例化
        Constructor<?>[] ctors = determineConstructorsFromBeanPostProcessors(beanClass, beanName);
        if (ctors != null ||
                mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_CONSTRUCTOR ||
                mbd.hasConstructorArgumentValues() || !ObjectUtils.isEmpty(args))  {
            //使用容器的自动装配特性，调用匹配的构造方法实例化
            return autowireConstructor(beanName, mbd, ctors, args);
        }

        // No special handling: simply use no-arg constructor.
        //使用默认的无参构造方法实例化
        return instantiateBean(beanName, mbd);
    }

经过上述的源码分析，咱们知道Spring这里对bean实例化有几种方式，分别是工厂方法实例化，容器自动装配以及使用默认的无参构造方法实例化。ide

而后咱们在来看populateBean方法是如何进行依赖注入的，源码以下：源码分析

//将Bean属性设置到生成的实例对象上
    protected void populateBean(String beanName, RootBeanDefinition mbd, @Nullable BeanWrapper bw) {
        //若是属性存在可是须要注入的对象为空，则抛出异常。
        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;
            }
        }

        // 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.
        //使得InstantiationAwareBeanPostProcessors有机会在属性注入以前修改bean的状态，例如支持一些属性类型的注入。
        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;
        }
        //获取容器在解析Bean定义资源时为BeanDefiniton中设置的属性值
        PropertyValues pvs = (mbd.hasPropertyValues() ? mbd.getPropertyValues() : null);

        //对依赖注入处理，首先处理autowiring自动装配的依赖注入
        if (mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_NAME ||
                mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_TYPE) {
            MutablePropertyValues newPvs = new MutablePropertyValues(pvs);

            // Add property values based on autowire by name if applicable.
            //根据Bean名称进行autowiring自动装配处理
            if (mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_NAME) {
                autowireByName(beanName, mbd, bw, newPvs);
            }

            // Add property values based on autowire by type if applicable.
            //根据Bean类型进行autowiring自动装配处理
            if (mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_TYPE) {
                autowireByType(beanName, mbd, bw, newPvs);
            }

            pvs = newPvs;
        }

        //对非autowiring的属性进行依赖注入处理
        boolean hasInstAwareBpps = hasInstantiationAwareBeanPostProcessors();
        boolean needsDepCheck = (mbd.getDependencyCheck() != RootBeanDefinition.DEPENDENCY_CHECK_NONE);

        if (hasInstAwareBpps || needsDepCheck) {
            if (pvs == null) {
                pvs = mbd.getPropertyValues();
            }
            PropertyDescriptor[] filteredPds = filterPropertyDescriptorsForDependencyCheck(bw, mbd.allowCaching);
            if (hasInstAwareBpps) {
                for (BeanPostProcessor bp : getBeanPostProcessors()) {
                    if (bp instanceof InstantiationAwareBeanPostProcessor) {
                        InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp;
                        pvs = ibp.postProcessPropertyValues(pvs, filteredPds, bw.getWrappedInstance(), beanName);
                        if (pvs == null) {
                            return;
                        }
                    }
                }
            }
            if (needsDepCheck) {
                checkDependencies(beanName, mbd, filteredPds, pvs);
            }
        }

        if (pvs != null) {
            //对属性进行注入
            applyPropertyValues(beanName, mbd, bw, pvs);
        }
    }

这里有也有几个方法须要注意，分别是autowireByName、autowireByType以及applyPropertyValues。
咱们先来看下autowireByName方法，源码以下：post

//根据名称对属性进行自动依赖注入
    protected void autowireByName(
            String beanName, AbstractBeanDefinition mbd, BeanWrapper bw, MutablePropertyValues pvs) {

        //对Bean对象中非简单属性(不是简单继承的对象，如8中原始类型，字符串，URL等都是简单属性)进行处理
        String[] propertyNames = unsatisfiedNonSimpleProperties(mbd, bw);
        for (String propertyName : propertyNames) {
            //若是Spring IOC容器中包含指定名称的Bean
            if (containsBean(propertyName)) {
                //调用getBean方法向IOC容器索取指定名称的Bean实例，迭代触发属性的初始化和依赖注入
                Object bean = getBean(propertyName);
                //为指定名称的属性赋予属性值
                pvs.add(propertyName, bean);
                //指定名称属性注册依赖Bean名称，进行属性依赖注入
                registerDependentBean(propertyName, beanName);
                if (logger.isDebugEnabled()) {
                    logger.debug("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");
                }
            }
        }
    }

能够看到这里经过找到Bean中非简单属性的属性，好比CharSequence类型、Number类型、Date类型、URL类型、URI类型、Locale类型、Class类型就会忽略，具体可见BeanUtils的isSimpleProperty方法，遍历全部被找到的属性，若是bean定义中包含了属性名，那么先实例化该属性名对应的bean，注册一下当前bean的依赖bean。this

而后咱们看下根据类型自动装配autowireByType方法的实现，源码以下：debug

//根据类型对属性进行自动依赖注入
    protected void autowireByType(
            String beanName, AbstractBeanDefinition mbd, BeanWrapper bw, MutablePropertyValues pvs) {

        //获取用户定义的类型转换器
        TypeConverter converter = getCustomTypeConverter();
        if (converter == null) {
            converter = bw;
        }

        //存放解析的要注入的属性
        Set<String> autowiredBeanNames = new LinkedHashSet<>(4);
        //对Bean对象中非简单属性(不是简单继承的对象，如8中原始类型，字符
        //URL等都是简单属性)进行处理
        String[] propertyNames = unsatisfiedNonSimpleProperties(mbd, bw);
        for (String propertyName : propertyNames) {
            try {
                //获取指定属性名称的属性描述器
                PropertyDescriptor pd = bw.getPropertyDescriptor(propertyName);
                // Don't try autowiring by type for type Object: never makes sense,
                // even if it technically is a unsatisfied, non-simple property.
                //不对Object类型的属性进行autowiring自动依赖注入
                if (Object.class != pd.getPropertyType()) {
                    //获取属性的setter方法
                    MethodParameter methodParam = BeanUtils.getWriteMethodParameter(pd);
                    // Do not allow eager init for type matching in case of a prioritized post-processor.
                    //检查指定类型是否能够被转换为目标对象的类型
                    boolean eager = !PriorityOrdered.class.isInstance(bw.getWrappedInstance());
                    //建立一个要被注入的依赖描述
                    DependencyDescriptor desc = new AutowireByTypeDependencyDescriptor(methodParam, eager);
                    //根据容器的Bean定义解析依赖关系，返回全部要被注入的Bean对象
                    Object autowiredArgument = resolveDependency(desc, beanName, autowiredBeanNames, converter);
                    if (autowiredArgument != null) {
                        //为属性赋值所引用的对象
                        pvs.add(propertyName, autowiredArgument);
                    }
                    for (String autowiredBeanName : autowiredBeanNames) {
                        //指定名称属性注册依赖Bean名称，进行属性依赖注入
                        registerDependentBean(autowiredBeanName, beanName);
                        if (logger.isDebugEnabled()) {
                            logger.debug("Autowiring by type from bean name '" + beanName + "' via property '" +
                                    propertyName + "' to bean named '" + autowiredBeanName + "'");
                        }
                    }
                    //释放已自动注入的属性
                    autowiredBeanNames.clear();
                }
            }
            catch (BeansException ex) {
                throw new UnsatisfiedDependencyException(mbd.getResourceDescription(), beanName, propertyName, ex);
            }
        }
    }

具体的解析过程主要看resolveDependency方法，这里感兴趣的同窗能够研究下具体过程。
最后咱们来看下applyPropertyValues方法，源码以下：

//解析并注入依赖属性的过程
    protected void applyPropertyValues(String beanName, BeanDefinition mbd, BeanWrapper bw, PropertyValues pvs) {
        if (pvs.isEmpty()) {
            return;
        }

        //封装属性值
        MutablePropertyValues mpvs = null;
        List<PropertyValue> original;

        if (System.getSecurityManager() != null) {
            if (bw instanceof BeanWrapperImpl) {
                //设置安全上下文，JDK安全机制
                ((BeanWrapperImpl) bw).setSecurityContext(getAccessControlContext());
            }
        }

        if (pvs instanceof MutablePropertyValues) {
            mpvs = (MutablePropertyValues) pvs;
            //属性值已经转换
            if (mpvs.isConverted()) {
                // Shortcut: use the pre-converted values as-is.
                try {
                    //为实例化对象设置属性值
                    bw.setPropertyValues(mpvs);
                    return;
                }
                catch (BeansException ex) {
                    throw new BeanCreationException(
                            mbd.getResourceDescription(), beanName, "Error setting property values", ex);
                }
            }
            //获取属性值对象的原始类型值
            original = mpvs.getPropertyValueList();
        }
        else {
            original = Arrays.asList(pvs.getPropertyValues());
        }

        //获取用户自定义的类型转换
        TypeConverter converter = getCustomTypeConverter();
        if (converter == null) {
            converter = bw;
        }
        //建立一个Bean定义属性值解析器，将Bean定义中的属性值解析为Bean实例对象的实际值
        BeanDefinitionValueResolver valueResolver = new BeanDefinitionValueResolver(this, beanName, mbd, converter);

        // Create a deep copy, resolving any references for values.

        //为属性的解析值建立一个拷贝，将拷贝的数据注入到实例对象中
        List<PropertyValue> deepCopy = new ArrayList<>(original.size());
        boolean resolveNecessary = false;
        for (PropertyValue pv : original) {
            //属性值不须要转换
            if (pv.isConverted()) {
                deepCopy.add(pv);
            }
            //属性值须要转换
            else {
                String propertyName = pv.getName();
                //原始的属性值，即转换以前的属性值
                Object originalValue = pv.getValue();
                //转换属性值，例如将引用转换为IOC容器中实例化对象引用
                Object resolvedValue = valueResolver.resolveValueIfNecessary(pv, originalValue);
                //转换以后的属性值
                Object convertedValue = resolvedValue;
                //属性值是否能够转换
                boolean convertible = bw.isWritableProperty(propertyName) &&
                        !PropertyAccessorUtils.isNestedOrIndexedProperty(propertyName);
                if (convertible) {
                    //使用用户自定义的类型转换器转换属性值
                    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.
                //存储转换后的属性值，避免每次属性注入时的转换工做
                if (resolvedValue == originalValue) {
                    if (convertible) {
                        //设置属性转换以后的值
                        pv.setConvertedValue(convertedValue);
                    }
                    deepCopy.add(pv);
                }
                //属性是可转换的，且属性原始值是字符串类型，且属性的原始类型值不是
                //动态生成的字符串，且属性的原始值不是集合或者数组类型
                else if (convertible && originalValue instanceof TypedStringValue &&
                        !((TypedStringValue) originalValue).isDynamic() &&
                        !(convertedValue instanceof Collection || ObjectUtils.isArray(convertedValue))) {
                    pv.setConvertedValue(convertedValue);
                    //从新封装属性的值
                    deepCopy.add(pv);
                }
                else {
                    resolveNecessary = true;
                    deepCopy.add(new PropertyValue(pv, convertedValue));
                }
            }
        }
        if (mpvs != null && !resolveNecessary) {
            //标记属性值已经转换过
            mpvs.setConverted();
        }

        // Set our (possibly massaged) deep copy.
        //进行属性依赖注入
        try {
            bw.setPropertyValues(new MutablePropertyValues(deepCopy));
        }
        catch (BeansException ex) {
            throw new BeanCreationException(
                    mbd.getResourceDescription(), beanName, "Error setting property values", ex);
        }
    }

这里主要是对须要转换的属性进行转换而后进行属性值的依赖注入。

至此属性的依赖注入分析结束，最后咱们看下initializeBean方法是如何对bean进行初始化操做的，其源码以下：

//初始容器建立的Bean实例对象，为其添加BeanPostProcessor后置处理器
    protected Object initializeBean(final String beanName, final Object bean, @Nullable RootBeanDefinition mbd) {
        //JDK的安全机制验证权限
        if (System.getSecurityManager() != null) {
            //实现PrivilegedAction接口的匿名内部类
            AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
                invokeAwareMethods(beanName, bean);
                return null;
            }, getAccessControlContext());
        }
        else {
            //为Bean实例对象包装相关属性，如名称，类加载器，所属容器等信息
            invokeAwareMethods(beanName, bean);
        }

        Object wrappedBean = bean;
        //对BeanPostProcessor后置处理器的postProcessBeforeInitialization
        //回调方法的调用，为Bean实例初始化前作一些处理
        if (mbd == null || !mbd.isSynthetic()) {
            wrappedBean = applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName);
        }

        //调用Bean实例对象初始化的方法，这个初始化方法是在Spring Bean定义配置
        //文件中经过init-method属性指定的
        try {
            invokeInitMethods(beanName, wrappedBean, mbd);
        }
        catch (Throwable ex) {
            throw new BeanCreationException(
                    (mbd != null ? mbd.getResourceDescription() : null),
                    beanName, "Invocation of init method failed", ex);
        }
        //对BeanPostProcessor后置处理器的postProcessAfterInitialization
        //回调方法的调用，为Bean实例初始化以后作一些处理
        if (mbd == null || !mbd.isSynthetic()) {
            wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);
        }

        return wrappedBean;
    }

至此，bean初始化操做的整体过程分析结束，固然中间存在一些细节方面的点没有分析清楚，还须要各位小伙伴自行研究，而后有什么问题能够留言，你们一块儿讨论一块儿进步。