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This article mainly introduces the relevant knowledge of what is the difference between Spring BeanFactory and FactoryBean, the content is detailed and easy to understand, the operation is simple and fast, and it has a certain reference value. I believe you will gain something after reading this Spring BeanFactory and FactoryBean. Let's take a look at it.

Foreword:

In Spring, IOC is a very important concept, its essence is map structure, storage container and business Bean information. But the difference between BeanFactory and FactoryBean is a very important knowledge point, which will be analyzed and explained with the source code in this article.

Distinguish and contact BeanFactory

In Spring, all Bean is managed by BeanFactory (that is, IOC containers). BeanFactory defines the basic form of the container and defines the basic interface and life cycle of the IOC container. There are also many implementation classes for BeanFactory, such as ApplicationContext, DefaultListableBeanFactory and XmlBeanFactory. Bean objects created by BeanFactory need to follow the following lifecycle forms, and Bean production is achieved through reflection mechanisms.

In English, Aware means conscious, and you can see that the lifecycle process of BeanFactory contains many Aware interfaces:

The following are the methods related to the life cycle of the BeanFactory interface, which are widely used by ApplicationContextAware, InitializingBean, and DisposableBean in project development.

The name used by BeanNameAware.setBeanName to set the Bean

BeanClassLoaderAware.setBeanClassLoader setup class loader

BeanFactoryAware.setBeanFactory setup bean Factory

ResourceLoaderAware.setResourceLoader setup Resource Loader

ApplicationEventPublisherAware.setApplicationEventPublisher setup event publisher

MessageSourceAware.setMessageSource Settings Information Resources

ApplicationContextAware.setApplicationContext sets the application context

ServletContextAware.setServletContext sets Servlet context

BeanPostProcessor.postProcessBeforeInitialization preprocessor

InitializingBean.afterPropertiesSet Bean initialization operation

RootBeanDefinition.getInitMethodName sets the name of the initialization method for Bean

BeanPostProcessor.postProcessAfterInitialization post processor

DisposableBean.destroy setting Bean destruction

The method of obtaining Bean destruction by RootBeanDefinition.getDestroyMethodName

By default, if you call the getBean method directly, you will return an object created by the factory, and if you want to get the Bean itself, you need to add the & symbol as a prefix.

FactoryBean

However, in some specific cases, the operation of instantiating Bean will be very complicated, and a large number of attributes need to be configured according to its requirements, so the configuration flexibility of Bean is limited, and FactoryBean is needed. This API can construct Bean objects according to the needs of users, instead of following the process of Bean lifecycle. Spring itself provides a lot of FactoryBean implementation, which hides a series of complex details of instantiation and brings convenience to the upper application. Since the beginning of Srping3.0, FactoryBean has supported generics, that is, the interface declaration has been changed to the form of FactoryBean. In the application of FactoryBean, SqlSessionFactoryBean is a good practice. In the process of operating the database, it provides a factory Factory to create SqlSession.

This is the end of the article on "what's the difference between Spring BeanFactory and FactoryBean". Thank you for reading! I believe that everyone has a certain understanding of the knowledge of "what is the difference between Spring BeanFactory and FactoryBean". If you want to learn more knowledge, you are welcome to follow the industry information channel.

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