7.普通bean和FactoryBean的区别

普通bean和FactoryBean的区别：前者定义什么类型就返回什么类型，后者不同

Teacher类

package Spring5.Student;

public class Teacher {
}

Student类

package Spring5.Student;

import org.springframework.beans.factory.FactoryBean;

public class Student implements FactoryBean<Teacher> {
    @Override
    public boolean isSingleton() {
        return FactoryBean.super.isSingleton();
    }

    @Override
    public Teacher getObject() throws Exception {
        Teacher t=new Teacher();
        return t;
    }

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

bean6.xml

<?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="Student" class="Spring5.Student.Student">

    </bean>
</beans>

测试类

public class TEST {
   
    //普通bean和FactoryBean的区别：前者定义什么类型就返回什么类型，后者不同
    @Test
    public void testBean6() {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean6.xml");
        Teacher t = context.getBean("Student", Teacher.class);
        System.out.println(t);
    }
}

测试结果

Spring5.Student.Teacher@79924b