spering getBean()

IOC:前面都是对bean定义的处理,postProcess已经实例化了。
解析bean的时候,把需要依赖注入的字段和方法,在postProcessMergedBeanDefinition方法中加到AutowiredAnnotationBeanPostProcessor的变量中,然后在AutowiredAnnotationBeanPostProcessor的作为入口,去依赖注入字段和方法。

protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) {
        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));  // 实例化一个转换器ConversionService
        }
        String[] weaverAwareNames = beanFactory.getBeanNamesForType(LoadTimeWeaverAware.class, false, false);
        for (String weaverAwareName : weaverAwareNames) {
            getBean(weaverAwareName);   //  没用,
        }
        beanFactory.preInstantiateSingletons();  //IOC
    }
    
public void preInstantiateSingletons() throws BeansException {
        List<String> beanNames;
        synchronized (this.beanDefinitionMap) {   //所有的beanDefinition,也就是bean的定义信息
            beanNames = new ArrayList<String>(this.beanDefinitionNames);  //所有的bean的名字
        }
        for (String beanName : beanNames) {//实例化所有的bean
            RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName);  // 合并功能,父子合并了的。
            if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) {  //不是抽象的,不是懒加载的,是单利,才会去实例化。
                if (isFactoryBean(beanName)) {//实现了FactoryBean接口
                    final FactoryBean<?> factory = (FactoryBean<?>) getBean(FACTORY_BEAN_PREFIX + beanName);
                    boolean isEagerInit;
                    if (System.getSecurityManager() != null && factory instanceof SmartFactoryBean) {//实现了SmartFactoryBean接口
                        isEagerInit = AccessController.doPrivileged(new PrivilegedAction<Boolean>() {
                            @Override
                            public Boolean run() {
                                return ((SmartFactoryBean<?>) factory).isEagerInit();  //调用这个bean的isEagerInit方法,返回true就实例化,
                            }
                        }, getAccessControlContext());
                    }
                    else {
                        isEagerInit = (factory instanceof SmartFactoryBean &&
                                ((SmartFactoryBean<?>) factory).isEagerInit()); //调用这个bean的isEagerInit方法,返回true就实例化,
                    }
                    if (isEagerInit) {//返回true就实例化,
                        getBean(beanName); //实例化
                    }
                }
                else {//没有实现了FactoryBean接口,
                    getBean(beanName);
                }
            }
        }
    }
    
解析有父类的bean,就是合并子类和父类的信息,涉及到子类覆盖父类。 protected RootBeanDefinition getMergedLocalBeanDefinition(String beanName) throws BeansException {
        RootBeanDefinition mbd = this.mergedBeanDefinitions.get(beanName);  // 先从缓存中拿
        if (mbd != null) {
            return mbd;
        }
        return getMergedBeanDefinition(beanName, getBeanDefinition(beanName));
    }

    <bean id="parent" class="com.zhuguang.jack.testbean.Parent" abstract="true">
    </bean>
    <bean id="son" class="com.zhuguang.jack.testbean.Son" parent="parent">
    </bean>    父类是用来继承的公共部分,不会被实例化。

protected RootBeanDefinition getMergedBeanDefinition(String beanName, BeanDefinition bd, BeanDefinition containingBd)throws BeanDefinitionStoreException {//beanName是bean的名字,bd是bean的定义

        synchronized (this.mergedBeanDefinitions) {  //mergedBeanDefinitions 是缓存,
            RootBeanDefinition mbd = null;
            if (containingBd == null) {
                mbd = this.mergedBeanDefinitions.get(beanName);
            }
            if (mbd == null) {
                if (bd.getParentName() == null) { //  bean没有父类,直接初始化一个RootBeanDefinition
                    if (bd instanceof RootBeanDefinition) {
                        mbd = ((RootBeanDefinition) bd).cloneBeanDefinition();  //也是调用 new RootBeanDefinition(bd);
                    }
                    else {
                        mbd = new RootBeanDefinition(bd);//bd是bean的定义信息,mbd是子类,bd是父类,这里做一个拷贝,是为了不污染db,而是使用重新初始化的mbd。
                    }
                }
                else {
                     //  bean有父类,要加载父类的信息
                    BeanDefinition pbd;
                    try {
                        String parentBeanName = transformedBeanName(bd.getParentName());  //获取父亲的名字,
                        if (!beanName.equals(parentBeanName)) {  //跟父的名字不一样,
                            pbd = getMergedBeanDefinition(parentBeanName);  //父类的bean定义,父类在有父类继续调用。
                        }
                    }
                    mbd = new RootBeanDefinition(pbd);   //pbd是父类,构造父类
                    mbd.overrideFrom(bd);//bd是bean的定义信息,mbd是父类,bd是子类,子类覆盖父类的信息,
                }

                if (containingBd == null && isCacheBeanMetadata() && isBeanEligibleForMetadataCaching(beanName)) {
                    this.mergedBeanDefinitions.put(beanName, mbd);  //加到缓存
                }
            }
            return mbd;
        }
    }
    
getBean(beanName);

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;

        //单利缓存中获取
        Object sharedInstance = getSingleton(beanName);
        if (sharedInstance != null && args == null) {
            bean = getObjectForBeanInstance(sharedInstance, name, beanName, null);
        }

        else {
            if (isPrototypeCurrentlyInCreation(beanName)) {//已经创建了
                throw new BeanCurrentlyInCreationException(beanName);
            }

            BeanFactory parentBeanFactory = getParentBeanFactory();//父类容器,从父类容器获取bean。
            if (parentBeanFactory != null && !containsBeanDefinition(beanName)) {
                String nameToLookup = originalBeanName(name);
                if (args != null) {
                    return (T) parentBeanFactory.getBean(nameToLookup, args);;//父类容器,从父类容器获取bean。
                }
                else {
                    return parentBeanFactory.getBean(nameToLookup, requiredType);;//父类容器,从父类容器获取bean。
                }
            }
            try {
                final RootBeanDefinition mbd = getMergedLocalBeanDefinition(beanName);//父子合并

                String[] dependsOn = mbd.getDependsOn();//依赖的bean,创建这个bean的时候先要创建哪些bean,
                if (dependsOn != null) {
                    for (String dependsOnBean : dependsOn) {
                        if (isDependent(beanName, dependsOnBean)) {//没有依赖关系
                            throw new BeanCreationException("Circular depends-on relationship between ‘" +
                                    beanName + "‘ and ‘" + dependsOnBean + "");
                        }
                        registerDependentBean(dependsOnBean, beanName);//增加依赖关系,
                        getBean(dependsOnBean);//先实例化依赖的bean
                    }
                }

                if (mbd.isSingleton()) {//单利
                    sharedInstance = getSingleton(beanName, new ObjectFactory<Object>() {
                        @Override
                        public Object getObject() throws BeansException {
                            try {
                                return createBean(beanName, mbd, args);
                            }
                        }
                    });
                    bean = getObjectForBeanInstance(sharedInstance, name, beanName, mbd);
                }

                else if (mbd.isPrototype()) {//多利
                    // 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);
                }

                else {
                    String scopeName = mbd.getScope();
                    final Scope scope = this.scopes.get(scopeName);
                    if (scope == null) {
                        throw new IllegalStateException("No Scope registered for scope ‘" + 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);
                    }
                }
            }
        }

        if (requiredType != null && bean != null && !requiredType.isAssignableFrom(bean.getClass())) {
            try {
                return getTypeConverter().convertIfNecessary(bean, requiredType);
            }
        }
        return (T) bean;
    }
    
单利:
sharedInstance = getSingleton(beanName, new ObjectFactory<Object>() {
    @Override
    public Object getObject() throws BeansException {
        try {
            return createBean(beanName, mbd, args);
        }
    }
});

public Object getSingleton(String beanName, ObjectFactory<?> singletonFactory) {
        synchronized (this.singletonObjects) {//缓存
            Object singletonObject = this.singletonObjects.get(beanName);
            if (singletonObject == null) {
                try {
                    singletonObject = singletonFactory.getObject();  //createBean
                }
                addSingleton(beanName, singletonObject);//缓存
            }
            return (singletonObject != NULL_OBJECT ? singletonObject : null);
        }
    }

protected Object createBean(final String beanName, final RootBeanDefinition mbd, final Object[] args)throws BeanCreationException {
        resolveBeanClass(mbd, beanName);   //bean的定义,bean的名字,拿出beanClass,
        try {
            mbd.prepareMethodOverrides();
        }
        try {
            Object bean = resolveBeforeInstantiation(beanName, mbd);//BeanPostProcessors已经实例化了,实例化之前插一脚,直接返回这个实例化的bean。后面不用走了。可以自己去实例化这个bean,spring就不会管这个bean的实例化了。下面有梨子InstantiationAwareBeanPostProcessorTest,
            if (bean != null) {
                return bean;
            }
        }
  //前面resolveBeforeInstantiation没有成功实例化出这个bean。spring来实例化这个bean。
        Object beanInstance = doCreateBean(beanName, mbd, args);
        return beanInstance;
    }

protected Object resolveBeforeInstantiation(String beanName, RootBeanDefinition mbd) {
        Object bean = null;
        if (!Boolean.FALSE.equals(mbd.beforeInstantiationResolved)) {
            if (mbd.hasBeanClass() && !mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) {
                bean = applyBeanPostProcessorsBeforeInstantiation(mbd.getBeanClass(), beanName);
                if (bean != null) {
                    bean = applyBeanPostProcessorsAfterInitialization(bean, beanName);  //先执行before在执行after方法,
                }
            }
            mbd.beforeInstantiationResolved = (bean != null);
        }
        return bean;
    }

protected Object applyBeanPostProcessorsBeforeInstantiation(Class<?> beanClass, String beanName)throws BeansException {
        for (BeanPostProcessor bp : getBeanPostProcessors()) {  //取出所有的BeanPostProcessors,
            if (bp instanceof InstantiationAwareBeanPostProcessor) {  // 实现InstantiationAwareBeanPostProcessor接口的自己写的类,可以自己去实例化这个bean,spring就不会管这个bean的实例化了。下面有梨子InstantiationAwareBeanPostProcessorTest,
                InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp;
                Object result = ibp.postProcessBeforeInstantiation(beanClass, beanName);  //通过所有的BeanPostProcessors来返回这个实例化的bean。spring就不会管这个bean的实例化了。
                if (result != null) {
                    return result;
                }
            }
        }
        return null;
    }
    
public class InstantiationAwareBeanPostProcessorTest implements InstantiationAwareBeanPostProcessor {
    @Override
    public Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) throws BeansException {
        try {
            return beanClass.newInstance();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        return null;
    }
    
protected Object doCreateBean(final String beanName, final RootBeanDefinition mbd, final Object[] args) {
        BeanWrapper instanceWrapper = null;
        if (mbd.isSingleton()) {
            instanceWrapper = this.factoryBeanInstanceCache.remove(beanName);//缓存,
        }
        if (instanceWrapper == null) {
            instanceWrapper = createBeanInstance(beanName, mbd, args);  // 包装类,通过反射实例创建完成。但是实例的属性还没有操作。不包括IOC的依赖注入。属性是没有值的。
        }
        final Object bean = (instanceWrapper != null ? instanceWrapper.getWrappedInstance() : null);
        Class<?> beanType = (instanceWrapper != null ? instanceWrapper.getWrappedClass() : null);

        synchronized (mbd.postProcessingLock) {
            if (!mbd.postProcessed) {
                applyMergedBeanDefinitionPostProcessors(mbd, beanType, beanName);   //下面解析, 
//解析完这个类需要依赖注入的字段和方法之后,在AutowiredAnnotationBeanPostProcessor增加一行记录factoryBeanTest=[FactoryBeanTest.woman(依赖注入字段), FactoryBeanTest.setWoman(com.zhuguang.jack.testbean.Woman)(依赖注入方法)]。 } mbd.postProcessed = true; } } boolean earlySingletonExposure = (mbd.isSingleton() && this.allowCircularReferences && isSingletonCurrentlyInCreation(beanName)); // 是单利并且允许循环依赖, if (earlySingletonExposure) { addSingletonFactory(beanName, new ObjectFactory<Object>() {//把ObjectFactory这个匿名对象加入到spring的三级缓存,在getSingleton从缓存取的时候,会调用三级缓存中的匿名对象ObjectFactory的getObject() 。 @Override public Object getObject() throws BeansException { return getEarlyBeanReference(beanName, mbd, bean); } }); } Object exposedObject = bean; try { populateBean(beanName, mbd, instanceWrapper); //IOC,依赖注入8中类型, if (exposedObject != null) { exposedObject = initializeBean(beanName, exposedObject, mbd); } } 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,"); } } } } try { registerDisposableBeanIfNecessary(beanName, bean, mbd); //注册, } return exposedObject; } protected BeanWrapper createBeanInstance(String beanName, RootBeanDefinition mbd, Object[] args) { Class<?> beanClass = resolveBeanClass(mbd, beanName);//拿到bean的class,class com.zhuguang.jack.testbean.A, if (mbd.getFactoryMethodName() != null) { return instantiateUsingFactoryMethod(beanName, mbd, args); //自己写的类去初始化,不要spring实例化, } return instantiateBean(beanName, mbd); } protected BeanWrapper instantiateBean(final String beanName, final RootBeanDefinition mbd) { try { Object beanInstance; final BeanFactory parent = this; if (System.getSecurityManager() != null) { //代码执行权限, beanInstance = AccessController.doPrivileged(new PrivilegedAction<Object>() { @Override public Object run() { return getInstantiationStrategy().instantiate(mbd, beanName, parent); } }, getAccessControlContext()); } else { beanInstance = getInstantiationStrategy().instantiate(mbd, beanName, parent); //通过反射,[email protected]实例创建完成。 } BeanWrapper bw = new BeanWrapperImpl(beanInstance); //包装, initBeanWrapper(bw); return bw; } } public Object instantiate(RootBeanDefinition beanDefinition, String beanName, BeanFactory owner) { if (beanDefinition.getMethodOverrides().isEmpty()) { synchronized (beanDefinition.constructorArgumentLock) { constructorToUse = (Constructor<?>) beanDefinition.resolvedConstructorOrFactoryMethod; if (constructorToUse == null) { final Class<?> clazz = beanDefinition.getBeanClass(); //拿到需要实例化的类, try { if (System.getSecurityManager() != null) { constructorToUse = AccessController.doPrivileged(new PrivilegedExceptionAction<Constructor<?>>() { @Override public Constructor<?> run() throws Exception { return clazz.getDeclaredConstructor((Class[]) null); //拿到构造器,无参构造器,为了防止循环依赖问题。 } }); } } } } return BeanUtils.instantiateClass(constructorToUse);//反射,实例化bean, } else { return instantiateWithMethodInjection(beanDefinition, beanName, owner);//Cglib } } protected void applyMergedBeanDefinitionPostProcessors(RootBeanDefinition mbd, Class<?> beanType, String beanName)throws BeansException { try { for (BeanPostProcessor bp : getBeanPostProcessors()) { if (bp instanceof MergedBeanDefinitionPostProcessor) {//实现这个接口的bean,才能做处理, MergedBeanDefinitionPostProcessor bdp = (MergedBeanDefinitionPostProcessor) bp; // 有一个AutowiredAnnotationBeanPostProcessor bdp.postProcessMergedBeanDefinition(mbd, beanType, beanName); } } } } AutowiredAnnotationBeanPostProcessor类的:依赖注入可以通过配置文件,也可以通过注解@Autowired,@Autowired,可以加载属性上面,也可以加载set方法上面。 public void postProcessMergedBeanDefinition(RootBeanDefinition beanDefinition, Class<?> beanType, String beanName) { if (beanType != null) { InjectionMetadata metadata = findAutowiringMetadata(beanName, beanType); //返回这个类,需要注解依赖注入的属性和方法, metadata.checkConfigMembers(beanDefinition); } } private InjectionMetadata findAutowiringMetadata(String beanName, Class<?> clazz) { String cacheKey = (StringUtils.hasLength(beanName) ? beanName : clazz.getName()); InjectionMetadata metadata = this.injectionMetadataCache.get(cacheKey); //AutowiredAnnotationBeanPostProcessor的缓存, if (InjectionMetadata.needsRefresh(metadata, clazz)) { synchronized (this.injectionMetadataCache) { metadata = this.injectionMetadataCache.get(cacheKey); if (InjectionMetadata.needsRefresh(metadata, clazz)) { metadata = buildAutowiringMetadata(clazz); //返回这个类,需要注解依赖注入的属性和方法, this.injectionMetadataCache.put(cacheKey, metadata); //解析完这个类需要依赖注入的字段和方法之后,在AutowiredAnnotationBeanPostProcessor增加一行记录factoryBeanTest = [ FactoryBeanTest.woman, FactoryBeanTest.setWoman(com.zhuguang.jack.testbean.Woman)],this=AutowiredAnnotationBeanPostProcessor } } } return metadata; } private InjectionMetadata buildAutowiringMetadata(Class<?> clazz) { LinkedList<InjectionMetadata.InjectedElement> elements = new LinkedList<InjectionMetadata.InjectedElement>(); Class<?> targetClass = clazz; do { LinkedList<InjectionMetadata.InjectedElement> currElements = new LinkedList<InjectionMetadata.InjectedElement>(); //InjectedElement是反射的属性或者方法对象, //@Autowired加载属性上面, for (Field field : targetClass.getDeclaredFields()) { // 拿到类的所有属性, AnnotationAttributes annotation = findAutowiredAnnotation(field); //获取字段的Autowired,Value,Inject 3种注解,其余注解不管,返回映射关系, if (annotation != null) { if (Modifier.isStatic(field.getModifiers())) { continue; } boolean required = determineRequiredStatus(annotation);//拿到注解的值, currElements.add(new AutowiredFieldElement(field, required)); //一个字段field对应一个AutowiredFieldElement,装到容器中。还没有涉及到IOC过程。 } } //@Autowired加载set方法上面, for (Method method : targetClass.getDeclaredMethods()) { // 拿到类的所有方法,有注解的方法是 FactoryBeanTest.setWoman(com.zhuguang.jack.testbean.Woman)。 @Autowired public void setWoman(Woman woman) { this.woman = woman; }, Method bridgedMethod = BridgeMethodResolver.findBridgedMethod(method); //方法的重载 AnnotationAttributes annotation = BridgeMethodResolver.isVisibilityBridgeMethodPair(method, bridgedMethod) ? findAutowiredAnnotation(bridgedMethod) : findAutowiredAnnotation(method); //找到这个方法上面有没有Autowired,Value,Inject 3种注解,其余注解不管, if (annotation != null && method.equals(ClassUtils.getMostSpecificMethod(method, clazz))) { if (Modifier.isStatic(method.getModifiers())) { continue; } boolean required = determineRequiredStatus(annotation);//拿到注解的值, PropertyDescriptor pd = BeanUtils.findPropertyForMethod(method);//拿到方法的类型对象PropertyDescriptor currElements.add(new AutowiredMethodElement(method, required, pd));//把method, required, pd包装成AutowiredMethodElement放到容器currElements中去, } } elements.addAll(0, currElements); targetClass = targetClass.getSuperclass(); } while (targetClass != null && targetClass != Object.class); //父类,也去解析父类, return new InjectionMetadata(clazz, elements); //返回这个类,需要注解依赖注入的属性和方法, } public AutowiredAnnotationBeanPostProcessor() { //AutowiredAnnotationBeanPostProcessor里面加了Autowired,Value,Inject 3种注解, this.autowiredAnnotationTypes.add(Autowired.class); this.autowiredAnnotationTypes.add(Value.class); ClassLoader cl = AutowiredAnnotationBeanPostProcessor.class.getClassLoader(); this.autowiredAnnotationTypes.add((Class<? extends Annotation>) cl.loadClass("javax.inject.Inject")); } singletonObjects是一级缓存,一个bean依赖注入完成之后,属性都完成了,才会存在在singletonObjects这个Map里面。 earlySingletonObjects是二级缓存,一个bean还没有完全实例化,有可能里面还有一些属性,还没有完全依赖注入完。 singletonFactories是三级缓存,里面存的是ObjectFactory对象。 二级三级缓存,就是为了解决循环依赖问题,A里面有B,B里面有A。A实例化的时候B没有实例化,此时A还是一个空壳子,会加到三级缓存,然后getBean(B),B实例化的时候发现有属性A,会去实例化getBean(A),此时A在三级缓存中,会调用这个三级缓存的getObject()方法。 protected Object getSingleton(String beanName, boolean allowEarlyReference) { Object singletonObject = this.singletonObjects.get(beanName);//从第一级取 if (singletonObject == null && isSingletonCurrentlyInCreation(beanName)) { synchronized (this.singletonObjects) { singletonObject = this.earlySingletonObjects.get(beanName);//从第二级取 if (singletonObject == null && allowEarlyReference) { ObjectFactory<?> singletonFactory = this.singletonFactories.get(beanName);//从第三级取 if (singletonFactory != null) { singletonObject = singletonFactory.getObject(); //三级缓存调用getObject(), this.earlySingletonObjects.put(beanName, singletonObject);//移到二级缓存, this.singletonFactories.remove(beanName);//从三级缓存删除, } } } } return (singletonObject != NULL_OBJECT ? singletonObject : null); } protected void addSingletonFactory(String beanName, ObjectFactory<?> singletonFactory) { synchronized (this.singletonObjects) { if (!this.singletonObjects.containsKey(beanName)) {//一级缓存没有 this.singletonFactories.put(beanName, singletonFactory);//放入三级缓存,准备上面的,调用三级缓存的getObject(), this.earlySingletonObjects.remove(beanName);//二级缓存移除 this.registeredSingletons.add(beanName); } } } protected Object getEarlyBeanReference(String beanName, RootBeanDefinition mbd, Object bean) { Object exposedObject = bean; if (bean != null && !mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) { for (BeanPostProcessor bp : getBeanPostProcessors()) { if (bp instanceof SmartInstantiationAwareBeanPostProcessor) { //这个接口, SmartInstantiationAwareBeanPostProcessor ibp = (SmartInstantiationAwareBeanPostProcessor) bp; exposedObject = ibp.getEarlyBeanReference(exposedObject, beanName); if (exposedObject == null) { return exposedObject; } } } } return exposedObject; } protected void populateBean(String beanName, RootBeanDefinition mbd, BeanWrapper bw) { PropertyValues pvs = mbd.getPropertyValues(); //拿到factoryBeanTest的需要依赖注入的属性,PropertyValues: length=1; bean property ‘woman‘ boolean continueWithPropertyPopulation = true; //当前bean的依赖注入到底要不要做, if (!mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) { for (BeanPostProcessor bp : getBeanPostProcessors()) { if (bp instanceof InstantiationAwareBeanPostProcessor) { // InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp; if (!ibp.postProcessAfterInstantiation(bw.getWrappedInstance(), beanName)) { //返回布尔值,当前bean的依赖注入要不要做, continueWithPropertyPopulation = false; break; } } } } if (!continueWithPropertyPopulation) { //为false,当前bean的依赖注入就不用做了, return; } boolean hasInstAwareBpps = hasInstantiationAwareBeanPostProcessors(); //有没有实现InstantiationAwareBeanPostProcessor接口, boolean needsDepCheck = (mbd.getDependencyCheck() != RootBeanDefinition.DEPENDENCY_CHECK_NONE); if (hasInstAwareBpps || needsDepCheck) { PropertyDescriptor[] filteredPds = filterPropertyDescriptorsForDependencyCheck(bw, mbd.allowCaching); if (hasInstAwareBpps) { for (BeanPostProcessor bp : getBeanPostProcessors()) { if (bp instanceof InstantiationAwareBeanPostProcessor) { //找到这个接口的类,包括spring的和自己的, InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp; pvs = ibp.postProcessPropertyValues(pvs, filteredPds, bw.getWrappedInstance(), beanName);//@Autoware,@Value的依赖注入。 AutowiredAnnotationBeanPostProcessor类的postProcessPropertyValues方法,依赖注入在这里。 if (pvs == null) { return; } } } } } applyPropertyValues(beanName, mbd, bw, pvs); //通过xml依赖注入, } AutowiredAnnotationBeanPostProcessor类: public PropertyValues postProcessPropertyValues(PropertyValues pvs, PropertyDescriptor[] pds, Object bean, String beanName) throws BeansException { InjectionMetadata metadata = findResourceMetadata(beanName, bean.getClass()); //从缓存取,需要依赖注入的字段和方法,[FactoryBeanTest.woman, .FactoryBeanTest.setWoman(com.zhuguang.jack.testbean.Woman)], try { metadata.inject(bean, beanName, pvs);//依赖注入在这里。 } return pvs; } public void inject(Object target, String beanName, PropertyValues pvs) throws Throwable { Collection<InjectedElement> elementsToIterate = (this.checkedElements != null ? this.checkedElements : this.injectedElements); //[FactoryBeanTest.woman, FactoryBeanTest.setWoman(com.zhuguang.jack.testbean.Woman)], if (!elementsToIterate.isEmpty()) { for (InjectedElement element : elementsToIterate) { element.inject(target, beanName, pvs); //目标对象[email protected],bean名字factoryBeanTest,需要依赖注入的字段或者方法[bean property ‘woman‘] 。依赖注入在这里。 } } } //依赖注入字段。依赖注入在这里。 protected void inject(Object bean, String beanName, PropertyValues pvs) throws Throwable { Field field = (Field) this.member; //FactoryBeanTest.woman try { Object value; if (this.cached) { value = resolvedCachedArgument(beanName, this.cachedFieldValue); } else { DependencyDescriptor desc = new DependencyDescriptor(field, this.required); desc.setContainingClass(bean.getClass()); Set<String> autowiredBeanNames = new LinkedHashSet<String>(1); TypeConverter typeConverter = beanFactory.getTypeConverter(); value = beanFactory.resolveDependency(desc, beanName, autowiredBeanNames, typeConverter);//拿到依赖注入的属性的值,[email protected] synchronized (this) { if (!this.cached) { if (value != null || this.required) { this.cachedFieldValue = desc; registerDependentBeans(beanName, autowiredBeanNames); } this.cached = true; } } } if (value != null) {//[email protected] ReflectionUtils.makeAccessible(field); field.set(bean, value); //字段设置值 } } } } public Object resolveDependency(DependencyDescriptor descriptor, String beanName, Set<String> autowiredBeanNames, TypeConverter typeConverter) throws BeansException { else { if (result == null) { result = doResolveDependency(descriptor, beanName, autowiredBeanNames, typeConverter); } return result;//[email protected] } } public Object doResolveDependency(DependencyDescriptor descriptor, String beanName, Set<String> autowiredBeanNames, TypeConverter typeConverter) throws BeansException { Class<?> type = descriptor.getDependencyType(); //class com.zhuguang.jack.testbean.Woman Object value = getAutowireCandidateResolver().getSuggestedValue(descriptor); if (value != null) { if (value instanceof String) { String strVal = resolveEmbeddedValue((String) value); BeanDefinition bd = (beanName != null && containsBean(beanName) ? getMergedBeanDefinition(beanName) : null); value = evaluateBeanDefinitionString(strVal, bd); } TypeConverter converter = (typeConverter != null ? typeConverter : getTypeConverter()); return (descriptor.getField() != null ? converter.convertIfNecessary(value, type, descriptor.getField()) : converter.convertIfNecessary(value, type, descriptor.getMethodParameter())); } if (type.isArray()) { //依赖注入的是数组 Class<?> componentType = type.getComponentType(); DependencyDescriptor targetDesc = new DependencyDescriptor(descriptor); targetDesc.increaseNestingLevel(); Map<String, Object> matchingBeans = findAutowireCandidates(beanName, componentType, targetDesc); if (matchingBeans.isEmpty()) { if (descriptor.isRequired()) { raiseNoSuchBeanDefinitionException(componentType, "array of " + componentType.getName(), descriptor); } return null; } if (autowiredBeanNames != null) { autowiredBeanNames.addAll(matchingBeans.keySet()); } TypeConverter converter = (typeConverter != null ? typeConverter : getTypeConverter()); Object result = converter.convertIfNecessary(matchingBeans.values(), type); if (this.dependencyComparator != null && result instanceof Object[]) { Arrays.sort((Object[]) result, this.dependencyComparator); } return result; } else if (Collection.class.isAssignableFrom(type) && type.isInterface()) { //依赖注入的是集合 Class<?> elementType = descriptor.getCollectionType(); if (elementType == null) { if (descriptor.isRequired()) { throw new FatalBeanException("No element type declared for collection [" + type.getName() + "]"); } return null; } DependencyDescriptor targetDesc = new DependencyDescriptor(descriptor); targetDesc.increaseNestingLevel(); Map<String, Object> matchingBeans = findAutowireCandidates(beanName, elementType, targetDesc); if (matchingBeans.isEmpty()) { if (descriptor.isRequired()) { raiseNoSuchBeanDefinitionException(elementType, "collection of " + elementType.getName(), descriptor); } return null; } if (autowiredBeanNames != null) { autowiredBeanNames.addAll(matchingBeans.keySet()); } TypeConverter converter = (typeConverter != null ? typeConverter : getTypeConverter()); Object result = converter.convertIfNecessary(matchingBeans.values(), type); if (this.dependencyComparator != null && result instanceof List) { Collections.sort((List<?>) result, this.dependencyComparator); } return result; } else if (Map.class.isAssignableFrom(type) && type.isInterface()) { //依赖注入的是MAp Class<?> keyType = descriptor.getMapKeyType(); if (keyType == null || !String.class.isAssignableFrom(keyType)) { if (descriptor.isRequired()) { throw new FatalBeanException("Key type [" + keyType + "] of map [" + type.getName() + "] must be assignable to [java.lang.String]"); } return null; } Class<?> valueType = descriptor.getMapValueType(); if (valueType == null) { if (descriptor.isRequired()) { throw new FatalBeanException("No value type declared for map [" + type.getName() + "]"); } return null; } DependencyDescriptor targetDesc = new DependencyDescriptor(descriptor); targetDesc.increaseNestingLevel(); Map<String, Object> matchingBeans = findAutowireCandidates(beanName, valueType, targetDesc); if (matchingBeans.isEmpty()) { if (descriptor.isRequired()) { raiseNoSuchBeanDefinitionException(valueType, "map with value type " + valueType.getName(), descriptor); } return null; } if (autowiredBeanNames != null) { autowiredBeanNames.addAll(matchingBeans.keySet()); } return matchingBeans; } else { //依赖注入不是数组,不是Map,不是集合,是基本类型或者对象, Map<String, Object> matchingBeans = findAutowireCandidates(beanName, type, descriptor); //{[email protected]},从bean工厂获取,最终还是通过getBean()方法获取。 if (matchingBeans.size() > 1) {//依赖注入的类有多个,报错。 String primaryBeanName = determinePrimaryCandidate(matchingBeans, descriptor); if (primaryBeanName == null) { throw new NoUniqueBeanDefinitionException(type, matchingBeans.keySet()); } if (autowiredBeanNames != null) { autowiredBeanNames.add(primaryBeanName); } return matchingBeans.get(primaryBeanName); } Map.Entry<String, Object> entry = matchingBeans.entrySet().iterator().next(); if (autowiredBeanNames != null) { autowiredBeanNames.add(entry.getKey()); } return entry.getValue();//[email protected] } } protected Map<String, Object> findAutowireCandidates( String beanName, Class<?> requiredType, DependencyDescriptor descriptor) { for (String candidateName : candidateNames) { if (!candidateName.equals(beanName) && isAutowireCandidate(candidateName, descriptor)) { result.put(candidateName, getBean(candidateName)); //还是通过getBean()方法获取需要依赖注入的属性的值, } } return result; } //方法的依赖注入,依赖注入在这里。通过反射给方法设置值,形参通过getBean()方法获取。 protected void inject(Object bean, String beanName, PropertyValues pvs) throws Throwable { else { Object arg = beanFactory.resolveDependency(desc, beanName, autowiredBeanNames, typeConverter); if (arg == null && !this.required) { arguments = null; break; } arguments[i] = arg; } } if (arguments != null) { ReflectionUtils.makeAccessible(method); method.invoke(bean, arguments); //通过反射给方法设置值,形参通过getBean()方法获取。 } } } 上main是通过注解的依赖注入,还有通过XML的依赖注入。 protected void applyPropertyValues(String beanName, BeanDefinition mbd, BeanWrapper bw, PropertyValues pvs) { //通过xml依赖注入, MutablePropertyValues mpvs = null; List<PropertyValue> original; if (System.getSecurityManager() != null) { if (bw instanceof BeanWrapperImpl) { ((BeanWrapperImpl) bw).setSecurityContext(getAccessControlContext()); } } if (pvs instanceof MutablePropertyValues) { mpvs = (MutablePropertyValues) pvs; if (mpvs.isConverted()) { try { bw.setPropertyValues(mpvs); return; } } original = mpvs.getPropertyValueList(); //[bean property ‘woman‘],需要xml依赖注入的属性, } else { original = Arrays.asList(pvs.getPropertyValues()); //[bean property ‘woman‘],需要xml依赖注入的属性, } TypeConverter converter = getCustomTypeConverter(); if (converter == null) { converter = bw; } BeanDefinitionValueResolver valueResolver = new BeanDefinitionValueResolver(this, beanName, mbd, converter); List<PropertyValue> deepCopy = new ArrayList<PropertyValue>(original.size()); boolean resolveNecessary = false; for (PropertyValue pv : original) { else { String propertyName = pv.getName();//woman, Object originalValue = pv.getValue();//<woman>,RuntimeBeanReference类型, Object resolvedValue = valueResolver.resolveValueIfNecessary(pv, originalValue); //beanFactory.getBean(refName);从bean工厂拿。因为依赖注入的属性有可能是一个引用,有可能是一个字符串需要转换成时间, Object convertedValue = resolvedValue; //[email protected] boolean convertible = bw.isWritableProperty(propertyName) &&!PropertyAccessorUtils.isNestedOrIndexedProperty(propertyName); if (convertible) { convertedValue = convertForProperty(resolvedValue, propertyName, bw, converter);//[email protected],类型转换之后的值。上面的valueResolver.resolveValueIfNecessary(pv, originalValue)有可能转换还不够,还需要转换, } if (resolvedValue == originalValue) { if (convertible) { pv.setConvertedValue(convertedValue); } deepCopy.add(pv); } else if (convertible && originalValue instanceof TypedStringValue && !((TypedStringValue) originalValue).isDynamic() && !(convertedValue instanceof Collection || ObjectUtils.isArray(convertedValue))) { pv.setConvertedValue(convertedValue); deepCopy.add(pv); } else { resolveNecessary = true; deepCopy.add(new PropertyValue(pv, convertedValue)); //pv, convertedValue一个是原始属性值,一个是转换之后的值。封装成PropertyValue, } } } try { bw.setPropertyValues(new MutablePropertyValues(deepCopy)); //设置值,MutablePropertyValues才是需要真正设置的值。 } } public void setPropertyValue(PropertyValue pv) throws BeansException { PropertyTokenHolder tokens = (PropertyTokenHolder) pv.resolvedTokens; if (tokens == null) { String propertyName = pv.getName(); BeanWrapperImpl nestedBw; try { nestedBw = getBeanWrapperForPropertyPath(propertyName); } tokens = getPropertyNameTokens(getFinalPath(nestedBw, propertyName)); if (nestedBw == this) { pv.getOriginalPropertyValue().resolvedTokens = tokens; } nestedBw.setPropertyValue(tokens, pv); } else { setPropertyValue(tokens, pv); } } protected Object initializeBean(final String beanName, final Object bean, RootBeanDefinition mbd) { else { invokeAwareMethods(beanName, bean); } Object wrappedBean = bean; if (mbd == null || !mbd.isSynthetic()) { wrappedBean = applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName); } try { invokeInitMethods(beanName, wrappedBean, mbd); } if (mbd == null || !mbd.isSynthetic()) { wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName); } return wrappedBean; } public Object applyBeanPostProcessorsBeforeInitialization(Object existingBean, String beanName) throws BeansException { Object result = existingBean; for (BeanPostProcessor beanProcessor : getBeanPostProcessors()) { result = beanProcessor.postProcessBeforeInitialization(result, beanName); if (result == null) { return result; } } return result; } private void invokeAwareMethods(final String beanName, final Object bean) { if (bean instanceof Aware) { if (bean instanceof BeanNameAware) { ((BeanNameAware) bean).setBeanName(beanName); } if (bean instanceof BeanClassLoaderAware) { ((BeanClassLoaderAware) bean).setBeanClassLoader(getBeanClassLoader()); } if (bean instanceof BeanFactoryAware) { ((BeanFactoryAware) bean).setBeanFactory(AbstractAutowireCapableBeanFactory.this); } } } protected void invokeInitMethods(String beanName, final Object bean, RootBeanDefinition mbd)throws Throwable { boolean isInitializingBean = (bean instanceof InitializingBean); if (isInitializingBean && (mbd == null || !mbd.isExternallyManagedInitMethod("afterPropertiesSet"))) { else { ((InitializingBean) bean).afterPropertiesSet(); //实例化bean的时候,调用afterPropertiesSet()方法,没有参数,做资源的加载(redis,mongodb的加载,),一个bean只会调用一次。在bean实例化之后,IOC之后调用。 } } if (mbd != null) { String initMethodName = mbd.getInitMethodName(); if (initMethodName != null && !(isInitializingBean && "afterPropertiesSet".equals(initMethodName)) && !mbd.isExternallyManagedInitMethod(initMethodName)) { invokeCustomInitMethod(beanName, bean, mbd); } } } protected void invokeCustomInitMethod(String beanName, final Object bean, RootBeanDefinition mbd) throws Throwable { String initMethodName = mbd.getInitMethodName(); //拿到init方法的名称,init-method, final Method initMethod = (mbd.isNonPublicAccessAllowed() ? BeanUtils.findMethod(bean.getClass(), initMethodName) : ClassUtils.getMethodIfAvailable(bean.getClass(), initMethodName)); //反射得到这个方法, else { try { ReflectionUtils.makeAccessible(initMethod); initMethod.invoke(bean); //调用, } } } 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()) { //单利,就缓存, registerDisposableBean(beanName, new DisposableBeanAdapter(bean, beanName, mbd, getBeanPostProcessors(), acc)); } else { Scope scope = this.scopes.get(mbd.getScope()); if (scope == null) { throw new IllegalStateException("No Scope registered for scope ‘" + mbd.getScope() + ""); } scope.registerDestructionCallback(beanName, new DisposableBeanAdapter(bean, beanName, mbd, getBeanPostProcessors(), acc)); } } } public void registerDisposableBean(String beanName, DisposableBean bean) { synchronized (this.disposableBeans) { this.disposableBeans.put(beanName, bean); } }
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