BeanFactory 是 IoC 底层容器；FactoryBean 是 创建 Bean 的一种方式，帮助实现复杂的初始化逻辑。

看个例子：

User.java

package constxiong;

public class User {
	
	private Integer id;
	
	private String name;

	public Integer getId() {
		return id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	@Override
	public String toString() {
		return "User [id=" + id + ", name=" + name + "]";
	}
	
}

UserFactoryBean 实现 FactoryBean 接口

package constxiong;

import org.springframework.beans.factory.FactoryBean;

/**
 * UserFactoryBean 实现 FactoryBean 接口，用于构造 User 的bean
 * @author ConstXiong
 */
public class UserFactoryBean implements FactoryBean<User> {

	@Override
	public User getObject() throws Exception {
		User user = new User();
		user.setId(2);
		user.setName("customUser");
		return user;
	}

	@Override
	public Class<?> getObjectType() {
		return User.class;
	}

	@Override
	public boolean isSingleton() {
		return true;
	}
	
}

spring 配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
	
	<bean id="constxiong" class="constxiong.User">
		<property name="id" value="1"/>
		<property name="name" value="constxiong"/>
	</bean>
	
	<bean id="customUser" class="constxiong.UserFactoryBean"></bean>

</beans>

测试代码

package constxiong;

import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;

/**
 * 测试 BeanFactory 与 FactoryBean 的区别
 * @author ConstXiong
 */
public class Test {
	
	public static void main(String[] args) {
		String xmlPath = "META-INF/spring-beanfactory-factorybean.xml";
		getBeanByBeanFactory(xmlPath);
	}

	/**
	 *  通过 DefaultListableBeanFactory 获取 bean
	 */
	private static void getBeanByBeanFactory(String xmlPath) {
		DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
		XmlBeanDefinitionReader xmlReader = new XmlBeanDefinitionReader(beanFactory);
		xmlReader.loadBeanDefinitions(xmlPath);
		User user = beanFactory.getBean("constxiong", User.class);
		System.out.println(user);
		
		user = beanFactory.getBean("customUser", User.class);
		System.out.println(user);
		
		// 获取 UserFactoryBean 本身
		UserFactoryBean userFactoryBean = beanFactory.getBean("&customUser", UserFactoryBean.class);
		System.out.println(userFactoryBean);
	}

}

说明：