[Spring5]IOC容器_Bean管理_工厂Bean

Posted 2022-03-04 唐火

IOC操作Bean管理（FactoryBean）

1.Spring有两种类型bean，一种普通bean，另外一种工厂bean（FactoryBean）

2.普通bean：在配置文件中定义bean类型就是返回类型

3.工厂bean：在配置文件定义bean类型可以和返回类型不一样

第一步 创建类，让这个类作为工厂bean，实现接口FactoryBean

第二步 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.atguigu.spring.collectiontype;

public class Course 
    private String cname;

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

package com.atguigu.spring.factoryBean;

import com.atguigu.spring.collectiontype.Course;
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("abc");
        return course;
    


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

    @Override
    public boolean isSingleton() 
        return false;
    

<?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.atguigu.spring.factoryBean.MyBean">

    </bean>

</beans>

测试：

package com.atguigu.spring.test;

import com.atguigu.spring.collectiontype.Book;
import com.atguigu.spring.collectiontype.Course;
import com.atguigu.spring.factoryBean.MyBean;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class testBook 


    @Test
    public void testCollection2()
    
        ApplicationContext context = new ClassPathXmlApplicationContext("bean3.xml");
        Course myBean = context.getBean("myBean", Course.class);
        System.out.println(myBean);