目录
1. 要研究的代码
- finishBeanFactoryInitialization
protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) { // Initialize conversion service for this context. if (beanFactory.containsBean(CONVERSION_SERVICE_BEAN_NAME) && beanFactory.isTypeMatch(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class)) { beanFactory.setConversionService( beanFactory.getBean(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class)); } // Register a default embedded value resolver if no bean post-processor // (such as a PropertyPlaceholderConfigurer bean) registered any before: // at this point, primarily for resolution in annotation attribute values. if (!beanFactory.hasEmbeddedValueResolver()) { beanFactory.addEmbeddedValueResolver(new StringValueResolver() { @Override public String resolveStringValue(String strVal) { return getEnvironment().resolvePlaceholders(strVal); } }); } // Initialize LoadTimeWeaverAware beans early to allow for registering their transformers early. String[] weaverAwareNames = beanFactory.getBeanNamesForType(LoadTimeWeaverAware.class, false, false); for (String weaverAwareName : weaverAwareNames) { getBean(weaverAwareName); } // Stop using the temporary ClassLoader for type matching. beanFactory.setTempClassLoader(null); // Allow for caching all bean definition metadata, not expecting further changes. beanFactory.freezeConfiguration(); // Instantiate all remaining (non-lazy-init) singletons. //实例化所有剩下的非懒加载的单实例bean beanFactory.preInstantiateSingletons(); } 这个步骤中尤其重要，他的preInstantiateSingletons会实例化所有非懒加载的单实例bean
2. 实例化所有非懒加载的单实例bean
2.1. 获取所有BeanName，一个个创建
- DefaultListableBeanFactory preInstantiateSingletons
public void preInstantiateSingletons() throws BeansException { if (logger.isDebugEnabled()) { logger.debug("Pre-instantiating singletons in " + this); } // Iterate over a copy to allow for init methods which in turn register new bean definitions. // While this may not be part of the regular factory bootstrap, it does otherwise work fine. List<String> beanNames = new ArrayList<String>(this.beanDefinitionNames); // Trigger initialization of all non-lazy singleton beans... //遍历所有bean名 for (String beanName : beanNames) { //封装成RootBeanDefinition RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName); //不是抽象的、是单例的、不是懒加载的 if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) { //是FactoryBean类型的（Spring提供的工厂模式，有一个getObject创建bean） if (isFactoryBean(beanName)) { final FactoryBean<?> factory = (FactoryBean<?>) getBean(FACTORY_BEAN_PREFIX + beanName); boolean isEagerInit; if (System.getSecurityManager() != null && factory instanceof SmartFactoryBean) { isEagerInit = AccessController.doPrivileged(new PrivilegedAction<Boolean>() { @Override public Boolean run() { return ((SmartFactoryBean<?>) factory).isEagerInit(); } }, getAccessControlContext()); } else { isEagerInit = (factory instanceof SmartFactoryBean && ((SmartFactoryBean<?>) factory).isEagerInit()); } if (isEagerInit) { getBean(beanName); } } //不是FactoryBean else { //调用AbstractBeanFactory的getBean getBean(beanName); } } } // Trigger post-initialization callback for all applicable beans... //遍历所有bean for (String beanName : beanNames) { Object singletonInstance = getSingleton(beanName); //如果这个bean是SmartInitializingSingleton类型的 if (singletonInstance instanceof SmartInitializingSingleton) { final SmartInitializingSingleton smartSingleton = (SmartInitializingSingleton) singletonInstance; if (System.getSecurityManager() != null) { AccessController.doPrivileged(new PrivilegedAction<Object>() { @Override public Object run() { smartSingleton.afterSingletonsInstantiated(); return null; } }, getAccessControlContext()); } else { //调用其afterSingletonsInstantiated方法 smartSingleton.afterSingletonsInstantiated(); } } } } 2.2. 创建单个bean
- AbstractBeanFactory getBean
@Override public Object getBean(String name) throws BeansException { //传入beanName return doGetBean(name, null, null, false); } 2.3. 看看之前创建bean有木有，没有再去创建【不是缓存，而是之前步骤创建的Bean】
- doGetBean
protected <T> T doGetBean( final String name, final Class<T> requiredType, final Object[] args, boolean typeCheckOnly) throws BeansException { final String beanName = transformedBeanName(name); Object bean; // Eagerly check singleton cache for manually registered singletons. //从之前预加载的bean中获取 Object sharedInstance = getSingleton(beanName); if (sharedInstance != null && args == null) { if (logger.isDebugEnabled()) { if (isSingletonCurrentlyInCreation(beanName)) { logger.debug("Returning eagerly cached instance of singleton bean '" + beanName + "' that is not fully initialized yet - a consequence of a circular reference"); } else { logger.debug("Returning cached instance of singleton bean '" + beanName + "'"); } } //之前预加载的bean中有 bean = getObjectForBeanInstance(sharedInstance, name, beanName, null); } //之前预加载的bean中没有 else { // Fail if we're already creating this bean instance: // We're assumably within a circular reference. if (isPrototypeCurrentlyInCreation(beanName)) { throw new BeanCurrentlyInCreationException(beanName); } // Check if bean definition exists in this factory. //通过父BeanFactory获取bean BeanFactory parentBeanFactory = getParentBeanFactory(); if (parentBeanFactory != null && !containsBeanDefinition(beanName)) { // Not found -> check parent. String nameToLookup = originalBeanName(name); if (args != null) { // Delegation to parent with explicit args. return (T) parentBeanFactory.getBean(nameToLookup, args); } else { // No args -> delegate to standard getBean method. return parentBeanFactory.getBean(nameToLookup, requiredType); } } if (!typeCheckOnly) { //标记当前bean已创建 markBeanAsCreated(beanName); } try { final RootBeanDefinition mbd = getMergedLocalBeanDefinition(beanName); checkMergedBeanDefinition(mbd, beanName, args); // Guarantee initialization of beans that the current bean depends on. //获取当前bean依赖的其他bean 指的是@DependsOn("。。。。") String[] dependsOn = mbd.getDependsOn(); if (dependsOn != null) { //遍历其他bean for (String dep : dependsOn) { //如果其他bean也依赖当前bean if (isDependent(beanName, dep)) { //抛出循环依赖异常 throw new BeanCreationException(mbd.getResourceDescription(), beanName, "Circular depends-on relationship between '" + beanName + "' and '" + dep + "'"); } //注册依赖bean registerDependentBean(dep, beanName); //获取依赖bean，获取不到则抛出不存在的异常 try { getBean(dep); } catch (NoSuchBeanDefinitionException ex) { throw new BeanCreationException(mbd.getResourceDescription(), beanName, "'" + beanName + "' depends on missing bean '" + dep + "'", ex); } } } //单实例的 // Create bean instance. if (mbd.isSingleton()) { //回调第二个参数的getObject方法，最后调用createBean方法创建bean sharedInstance = getSingleton(beanName, new ObjectFactory<Object>() { @Override public Object getObject() throws BeansException { try { //创建bean实例 return createBean(beanName, mbd, args); } //创建失败销毁bean catch (BeansException ex) { // Explicitly remove instance from singleton cache: It might have been put there // eagerly by the creation process, to allow for circular reference resolution. // Also remove any beans that received a temporary reference to the bean. destroySingleton(beanName); throw ex; } } }); bean = getObjectForBeanInstance(sharedInstance, name, beanName, mbd); } //prototype的 else if (mbd.isPrototype()) { // It's a prototype -> create a new instance. Object prototypeInstance = null; try { beforePrototypeCreation(beanName); prototypeInstance = createBean(beanName, mbd, args); } finally { afterPrototypeCreation(beanName); } bean = getObjectForBeanInstance(prototypeInstance, name, beanName, mbd); } //其他的：session等 else { String scopeName = mbd.getScope(); final Scope scope = this.scopes.get(scopeName); if (scope == null) { throw new IllegalStateException("No Scope registered for scope name '" + scopeName + "'"); } try { Object scopedInstance = scope.get(beanName, new ObjectFactory<Object>() { @Override public Object getObject() throws BeansException { beforePrototypeCreation(beanName); try { return createBean(beanName, mbd, args); } finally { afterPrototypeCreation(beanName); } } }); bean = getObjectForBeanInstance(scopedInstance, name, beanName, mbd); } catch (IllegalStateException ex) { throw new BeanCreationException(beanName, "Scope '" + scopeName + "' is not active for the current thread; consider " + "defining a scoped proxy for this bean if you intend to refer to it from a singleton", ex); } } } catch (BeansException ex) { cleanupAfterBeanCreationFailure(beanName); throw ex; } } // Check if required type matches the type of the actual bean instance. if (requiredType != null && bean != null && !requiredType.isInstance(bean)) { try { return getTypeConverter().convertIfNecessary(bean, requiredType); } catch (TypeMismatchException ex) { if (logger.isDebugEnabled()) { logger.debug("Failed to convert bean '" + name + "' to required type '" + ClassUtils.getQualifiedName(requiredType) + "'", ex); } throw new BeanNotOfRequiredTypeException(name, requiredType, bean.getClass()); } } return (T) bean; } 2.4. 从缓存中获取，没有再创建
- DefaultSingletonBeanRegistry getSingleton
public Object getSingleton(String beanName, ObjectFactory<?> singletonFactory) { Assert.notNull(beanName, "'beanName' must not be null"); //加锁 synchronized (this.singletonObjects) { //从缓存map中获取 Object singletonObject = this.singletonObjects.get(beanName); if (singletonObject == null) { if (this.singletonsCurrentlyInDestruction) { throw new BeanCreationNotAllowedException(beanName, "Singleton bean creation not allowed while singletons of this factory are in destruction " + "(Do not request a bean from a BeanFactory in a destroy method implementation!)"); } if (logger.isDebugEnabled()) { logger.debug("Creating shared instance of singleton bean '" + beanName + "'"); } //bean创建之前调用 beforeSingletonCreation(beanName); boolean newSingleton = false; boolean recordSuppressedExceptions = (this.suppressedExceptions == null); if (recordSuppressedExceptions) { this.suppressedExceptions = new LinkedHashSet<Exception>(); } try { //通过beanFactory创建bean singletonObject = singletonFactory.getObject(); newSingleton = true; } catch (IllegalStateException ex) { // Has the singleton object implicitly appeared in the meantime -> // if yes, proceed with it since the exception indicates that state. singletonObject = this.singletonObjects.get(beanName); if (singletonObject == null) { throw ex; } } catch (BeanCreationException ex) { if (recordSuppressedExceptions) { for (Exception suppressedException : this.suppressedExceptions) { ex.addRelatedCause(suppressedException); } } throw ex; } finally { if (recordSuppressedExceptions) { this.suppressedExceptions = null; } //bean创建之后调用 afterSingletonCreation(beanName); } if (newSingleton) { //把新创建的bean放入map中（ioc容器） addSingleton(beanName, singletonObject); } } return (singletonObject != NULL_OBJECT ? singletonObject : null); } } 2.5. 先看看能不能返回代理对象，不能再创建
- AbstractAutowireCapableBeanFactory createBean
protected Object createBean(String beanName, RootBeanDefinition mbd, Object[] args) throws BeanCreationException { if (logger.isDebugEnabled()) { logger.debug("Creating instance of bean '" + beanName + "'"); } //bean的定义 RootBeanDefinition mbdToUse = mbd; // Make sure bean class is actually resolved at this point, and // clone the bean definition in case of a dynamically resolved Class // which cannot be stored in the shared merged bean definition. //拿到bean的类型 Class<?> resolvedClass = resolveBeanClass(mbd, beanName); if (resolvedClass != null && !mbd.hasBeanClass() && mbd.getBeanClassName() != null) { mbdToUse = new RootBeanDefinition(mbd); mbdToUse.setBeanClass(resolvedClass); } // Prepare method overrides. try { mbdToUse.prepareMethodOverrides(); } catch (BeanDefinitionValidationException ex) { throw new BeanDefinitionStoreException(mbdToUse.getResourceDescription(), beanName, "Validation of method overrides failed", ex); } try { // Give BeanPostProcessors a chance to return a proxy instead of the target bean instance. //这里BeanPostProcessor可以返回代理对象 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); } //真正创建bean Object beanInstance = doCreateBean(beanName, mbdToUse, args); if (logger.isDebugEnabled()) { logger.debug("Finished creating instance of bean '" + beanName + "'"); } return beanInstance; } 2.5.1. 从代理对象中获取
2.5.1.1. 第一次创建业务bean进到这里的时候并不会返回代理对象
举个例子，如果我们有一个业务Bean叫Calc，他的代理Bean叫CalcProxy
-
第一次从容器中获取Calc Bean的场景
- 从容器中获取Calc Bean
- 进入到这里的时候既没有Bean Calc也没有Bean CalcProxy，所以不会返回代理bean
- 真正创建业务Bean Calc
- 然后调用
执行所有PostProcessor的postProcessAfterInitialization方法创建代理对象
-
第二次从容器中获取Calc Bean的场景
- 从容器中获取Calc Bean
- 由于容器中没有，需要先创建业务Bean Calc
- 进入到这里的时候已经有了代理Bean CalcProxy，返回
-
resolveBeforeInstantiation
protected Object resolveBeforeInstantiation(String beanName, RootBeanDefinition mbd) { Object bean = null; if (!Boolean.FALSE.equals(mbd.beforeInstantiationResolved)) { // Make sure bean class is actually resolved at this point. //调用AbstractBeanFactory的hasInstantiationAwareBeanPostProcessors方法查看是否包含InstantiationAwareBeanPostProcessors类型的PostProcessor if (!mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) { Class<?> targetType = determineTargetType(beanName, mbd); if (targetType != null) { //调用InstantiationAwareBeanPostProcessor类型的postProcessBeforeInstantiation方法获取代理对象 bean = applyBeanPostProcessorsBeforeInstantiation(targetType, beanName); if (bean != null) { //代理对象不为空那么调用postProcessAfterInitialization方法操作bean bean = applyBeanPostProcessorsAfterInitialization(bean, beanName); } } } mbd.beforeInstantiationResolved = (bean != null); } return bean; } 通过调用InstantiationAwareBeanPostProcessor类型的postProcessBeforeInstantiation方法获取代理对象，有的话再调用postProcessAfterInitialization方法操作bean，并返回
2.5.1.2. 在实例化之前调用
- applyBeanPostProcessorsBeforeInstantiation
protected Object applyBeanPostProcessorsBeforeInstantiation(Class<?> beanClass, String beanName) { //遍历所有BeanPostProcessor for (BeanPostProcessor bp : getBeanPostProcessors()) { //如果是InstantiationAwareBeanPostProcessor类型的 if (bp instanceof InstantiationAwareBeanPostProcessor) { InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp; //那么调用postProcessBeforeInstantiation方法获取代理对象 Object result = ibp.postProcessBeforeInstantiation(beanClass, beanName); if (result != null) { return result; } } } return null; } 2.5.1.3. 如果有代理对象那么调用
- applyBeanPostProcessorsAfterInitialization
public Object applyBeanPostProcessorsAfterInitialization(Object existingBean, String beanName) throws BeansException { Object result = existingBean; //遍历所有BeanPostProcessor for (BeanPostProcessor processor : getBeanPostProcessors()) { //调用postProcessAfterInitialization方法操作bean result = processor.postProcessAfterInitialization(result, beanName); if (result == null) { return result; } } return result; } 2.6. 真正创建bean实例
- doCreateBean
protected Object doCreateBean(final String beanName, final RootBeanDefinition mbd, final Object[] args) throws BeanCreationException { // Instantiate the bean. BeanWrapper instanceWrapper = null; if (mbd.isSingleton()) { instanceWrapper = this.factoryBeanInstanceCache.remove(beanName); } if (instanceWrapper == null) { //创建bean对象 instanceWrapper = createBeanInstance(beanName, mbd, args); } final Object bean = (instanceWrapper != null ? instanceWrapper.getWrappedInstance() : null); Class<?> beanType = (instanceWrapper != null ? instanceWrapper.getWrappedClass() : null); mbd.resolvedTargetType = beanType; // Allow post-processors to modify the merged bean definition. synchronized (mbd.postProcessingLock) { if (!mbd.postProcessed) { try { //调用MergedBeanDefinitionPostProcessor的postProcessMergedBeanDefinition方法 applyMergedBeanDefinitionPostProcessors(mbd, beanType, beanName); } catch (Throwable ex) { throw new BeanCreationException(mbd.getResourceDescription(), beanName, "Post-processing of merged bean definition failed", ex); } mbd.postProcessed = true; } } // Eagerly cache singletons to be able to resolve circular references // even when triggered by lifecycle interfaces like BeanFactoryAware. 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, new ObjectFactory<Object>() { @Override public Object getObject() throws BeansException { return getEarlyBeanReference(beanName, mbd, bean); } }); } // Initialize the bean instance. Object exposedObject = bean; try { //为bean的属性赋值 populateBean(beanName, mbd, instanceWrapper); if (exposedObject != null) { //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); } } if (earlySingletonExposure) { Object earlySingletonReference = getSingleton(beanName, false); if (earlySingletonReference != null) { if (exposedObject == bean) { exposedObject = earlySingletonReference; } else if (!this.allowRawInjectionDespiteWrapping && hasDependentBean(beanName)) { String[] dependentBeans = getDependentBeans(beanName); Set<String> actualDependentBeans = new LinkedHashSet<String>(dependentBeans.length); for (String dependentBean : dependentBeans) { if (!removeSingletonIfCreatedForTypeCheckOnly(dependentBean)) { actualDependentBeans.add(dependentBean); } } if (!actualDependentBeans.isEmpty()) { throw new BeanCurrentlyInCreationException(beanName, "Bean with name '" + beanName + "' has been injected into other beans [" + StringUtils.collectionToCommaDelimitedString(actualDependentBeans) + "] in its raw version as part of a circular reference, but has eventually been " + "wrapped. This means that said other beans do not use the final version of the " + "bean. This is often the result of over-eager type matching - consider using " + "'getBeanNamesOfType' with the 'allowEagerInit' flag turned off, for example."); } } } } // Register bean as disposable. try { //注册bean的销毁方法，registerDisposableBeanIfNecessary 不是调用(beanName, bean, mbd); } catch (BeanDefinitionValidationException ex) { throw new BeanCreationException( mbd.getResourceDescription(), beanName, "Invalid destruction signature", ex); } return exposedObject; } 创建实例的时候分成以下几个步骤
- 创建bean实例
- 为bean的属性赋值
- 初始化bean
2.6.1. 创建bean实例
- createBeanInstance
protected BeanWrapper createBeanInstance(String beanName, RootBeanDefinition mbd, Object[] args) { // Make sure bean class is actually resolved at this point. //获取bean的类型 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()); } //使用工厂方法创建bean if (mbd.getFactoryMethodName() != null) { return instantiateUsingFactoryMethod(beanName, mbd, args); } // Shortcut when re-creating the same bean... //调用bean的有参构造方法 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. //调用bean的无参构造方法 return instantiateBean(beanName, mbd); } 2.6.2. 为bean的属性赋值
- populateBean
protected void populateBean(String beanName, RootBeanDefinition mbd, BeanWrapper bw) { //拿到所有的属性值 PropertyValues pvs = mbd.getPropertyValues(); if (bw == null) { if (!pvs.isEmpty()) { 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. boolean continueWithPropertyPopulation = true; //有InstantiationAwareBeanPostProcessor类型的PostProcessor if (!mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) { //遍历所有PostProcessor for (BeanPostProcessor bp : getBeanPostProcessors()) { //调用InstantiationAwareBeanPostProcessor的postProcessAfterInstantiation方法 if (bp instanceof InstantiationAwareBeanPostProcessor) { InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp; if (!ibp.postProcessAfterInstantiation(bw.getWrappedInstance(), beanName)) { continueWithPropertyPopulation = false; break; } } } } if (!continueWithPropertyPopulation) { return; } 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. if (mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_NAME) { autowireByName(beanName, mbd, bw, newPvs); } // Add property values based on autowire by type if applicable. 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); if (hasInstAwareBpps || needsDepCheck) { PropertyDescriptor[] filteredPds = filterPropertyDescriptorsForDependencyCheck(bw, mbd.allowCaching); if (hasInstAwareBpps) { //遍历所有PostProcessor for (BeanPostProcessor bp : getBeanPostProcessors()) { //调用InstantiationAwareBeanPostProcessor的postProcessPropertyValues方法 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); } } //调用setter方法为属性赋值 applyPropertyValues(beanName, mbd, bw, pvs); } 属性赋值有三个操作
- 调用InstantiationAwareBeanPostProcessor的postProcessAfterInstantiation方法
- 调用InstantiationAwareBeanPostProcessor的postProcessPropertyValues方法
- 调用setter方法为属性赋值
2.6.3. 初始化bean
- initializeBean
protected Object initializeBean(final String beanName, final Object bean, RootBeanDefinition mbd) { if (System.getSecurityManager() != null) { AccessController.doPrivileged(new PrivilegedAction<Object>() { @Override public Object run() { invokeAwareMethods(beanName, bean); return null; } }, getAccessControlContext()); } else { //执行XXXAware接口的方法 invokeAwareMethods(beanName, bean); } Object wrappedBean = bean; if (mbd == null || !mbd.isSynthetic()) { //执行所有PostProcessor的postProcessBeforeInitialization方法 wrappedBean = applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName); } try { //调用自定义的初始化方法 invokeInitMethods(beanName, wrappedBean, mbd); } catch (Throwable ex) { throw new BeanCreationException( (mbd != null ? mbd.getResourceDescription() : null), beanName, "Invocation of init method failed", ex); } if (mbd == null || !mbd.isSynthetic()) { //调用所有BeanPostProcessor的postProcessAfterInitialization方法 wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName); } return wrappedBean; } 2.6.3.1. 执行所有BeanPostProcessor的postProcessBeforeInitialization方法
- applyBeanPostProcessorsBeforeInitialization
public Object applyBeanPostProcessorsBeforeInitialization(Object existingBean, String beanName) throws BeansException { Object result = existingBean; //遍历所有PostProcessor，调用postProcessBeforeInitialization方法 for (BeanPostProcessor processor : getBeanPostProcessors()) { result = processor.postProcessBeforeInitialization(result, beanName); if (result == null) { return result; } } return result; } 2.6.3.2. 调用自定义的初始化方法【InitializingBean】
- invokeInitMethods
protected void invokeInitMethods(String beanName, final Object bean, RootBeanDefinition mbd) throws Throwable { //是InitializingBean对象 boolean isInitializingBean = (bean instanceof InitializingBean); if (isInitializingBean && (mbd == null || !mbd.isExternallyManagedInitMethod("afterPropertiesSet"))) { if (logger.isDebugEnabled()) { logger.debug("Invoking afterPropertiesSet() on bean with name '" + beanName + "'"); } if (System.getSecurityManager() != null) { try { AccessController.doPrivileged(new PrivilegedExceptionAction<Object>() { @Override public Object run() throws Exception { ((InitializingBean) bean).afterPropertiesSet(); return null; } }, getAccessControlContext()); } catch (PrivilegedActionException pae) { throw pae.getException(); } } else { //调用bean的afterPropertiesSet方法 ((InitializingBean) bean).afterPropertiesSet(); } } if (mbd != null) { String initMethodName = mbd.getInitMethodName(); if (initMethodName != null && !(isInitializingBean && "afterPropertiesSet".equals(initMethodName)) && !mbd.isExternallyManagedInitMethod(initMethodName)) { //执行自定义的初始化方法 invokeCustomInitMethod(beanName, bean, mbd); } } } 2.6.3.3. 调用所有BeanPostProcessor的postProcessAfterInitialization方法
这里会创建代理bean
- applyBeanPostProcessorsAfterInitialization
public Object applyBeanPostProcessorsAfterInitialization(Object existingBean, String beanName) throws BeansException { Object result = existingBean; //遍历所有BeanPostProcessor for (BeanPostProcessor processor : getBeanPostProcessors()) { //调用postProcessAfterInitialization方法 result = processor.postProcessAfterInitialization(result, beanName); if (result == null) { return result; } } return result; } 2.6.4. 注册bean的销毁方法
- registerDisposableBeanIfNecessary
protected void registerDisposableBeanIfNecessary(String beanName, Object bean, RootBeanDefinition mbd) { AccessControlContext acc = (System.getSecurityManager() != null ? getAccessControlContext() : null); if (!mbd.isPrototype() && requiresDestruction(bean, mbd)) { if (mbd.isSingleton()) { // Register a DisposableBean implementation that performs all destruction // work for the given bean: DestructionAwareBeanPostProcessors, // DisposableBean interface, custom destroy method. 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() + "'"); } scope.registerDestructionCallback(beanName, new DisposableBeanAdapter(bean, beanName, mbd, getBeanPostProcessors(), acc)); } } } 
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