IOC操作Bean管理 (FactoryBean)

Spring有两种类型的bean，一种是普通的bean，另一种是工厂bean(FactoryBean)

普通bean

在配置文件中定义bean类型就是返回类型

工厂bean

在配置文件定义bean类型可以和返回类型不一样

创建类，让这个类作为工厂bean，实现接口FactoryBean

实现接口里面的方法，在实现的方法中定义返回的bean类型

package com.test2;

public class Course {
    private String cname;

    public void setCname(String cname) {
        this.cname = cname;
    }
}

package com.test2;

import org.springframework.beans.factory.FactoryBean;

public class MyBean implements FactoryBean<Course> {

    //定义返回bean
    @Override
    public Course getObject() throws Exception {
        Course course = new Course();
        course.setCname("adc");
        return course;
    }

    @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="myBean" class="com.test2.MyBean"/>

</beans>

package com.test2;


import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyBeanTest {
    @Test
    public void test(){
        ApplicationContext context = new ClassPathXmlApplicationContext("spring6.xml");
        MyBean myBean = context.getBean("myBean", MyBean.class);
        System.out.println("myBean = " + myBean);
    }

    @Test
    public void test1(){
        ApplicationContext context = new ClassPathXmlApplicationContext("spring6.xml");
        Course course = context.getBean("myBean", Course.class);
        System.out.println("course = " + course);
    }
}