Spring5 工厂Bean

一、工厂Bean

在配置文件中定义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

二、创建类

package com.leo.spring5.factorybean;

import com.leo.spring5.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 FactoryBean.super.isSingleton();
    }
}

package com.leo.spring5.collectiontype;

// 课程类
public class Course {
    private String cname;

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

    @Override
    public String toString() {
        return "Course{" +
                "cname='" + cname + '\'' +
                '}';
    }
}

三、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"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:util="http://www.springframework.org/schema/util"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd">

    <bean id="myBean" class="com.leo.spring5.factorybean.MyBean">

    </bean>
</beans>

四、测试

package com.leo.spring5.testdemo;

import com.leo.spring5.collectiontype.Course;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestBean {

    @Test
    public void test() {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean7.xml");
        Course course = context.getBean("myBean", Course.class);
        System.out.println(course);
    }
}

五、执行结果