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普通的Bean：在配置文件中定义bean类型就是返回类型

FactoryBean：在配置文件中定义bean类型可以和返回类型不一样

package factory;

import org.springframework.beans.factory.FactoryBean;
import pojo.User;

public class Person implements FactoryBean<User> {

    //定义返回的Bean
    @Override
    public User getObject() throws Exception {
        User user = new User();
        user.setUserName("Tom");
        return user;
    }

    @Override
    public Class<?> getObjectType() {
        return null;
    }

    @Override
    public boolean isSingleton() {
        return FactoryBean.super.isSingleton();
    }
}

<?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="person" class="factory.Person"></bean>
</beans>

import factory.Person;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import pojo.User;

public class testSpring {
    @Test
    public void testPerson() {
        //加载配置文件
        ApplicationContext context = new ClassPathXmlApplicationContext("Person.xml");

        //获取配置文件创建的对象
        User user = context.getBean("person", User.class);  //配置文件中定义的bean类型Person，这里返回的是User

        System.out.println(user.toString()); //
    }
}