protected Object getObjectForBeanInstance( Object beanInstance, String name, String beanName, @Nullable RootBeanDefinition mbd) { // Don't let calling code try to dereference the factory if the bean isn't a factory. if (BeanFactoryUtils.isFactoryDereference(name)) { if (beanInstance instanceof NullBean) { return beanInstance; } if (!(beanInstance instanceof FactoryBean)) { throw new BeanIsNotAFactoryException(transformedBeanName(name), beanInstance.getClass()); } } // Now we have the bean instance, which may be a normal bean or a FactoryBean. // If it's a FactoryBean, we use it to create a bean instance, unless the // caller actually wants a reference to the factory. // 1.如果实例不是FactoryBean类型的，或者name是以&号开头的，则直接返回实例（这里就FactoryBeanDemo这个类） if (!(beanInstance instanceof FactoryBean) || BeanFactoryUtils.isFactoryDereference(name)) { return beanInstance; } // 2.如果代码能走下来，则说明 beanName不是以&开头，并且beanInstance是FactoryBean类型的 Object object = null; if (mbd == null) { // 3.从factoryBeanObjectCache缓存里面拿FactoryBean类型的实例 object = getCachedObjectForFactoryBean(beanName); } if (object == null) { // Return bean instance from factory. FactoryBean<?> factory = (FactoryBean<?>) beanInstance; // Caches object obtained from FactoryBean if it is a singleton. if (mbd == null && containsBeanDefinition(beanName)) { mbd = getMergedLocalBeanDefinition(beanName); } boolean synthetic = (mbd != null && mbd.isSynthetic()); // 4.重点看，调用了FactoryBean的getObject方法 object = getObjectFromFactoryBean(factory, beanName, !synthetic); } return object; } 调用getObject()方法 缓存到factoryBeanObjectCache中 自己实现的接口
