Spring之FactoryBean

public class Car {
    
    private String name;
    private double price;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public double getPrice() {
        return price;
    }
    public void setPrice(double price) {
        this.price = price;
    }
    @Override
    public String toString() {
        return "Car [name=" + name + ", price=" + price + "]";
    }
    public Car(String name, double price) {
        super();
        this.name = name;
        this.price = price;
    }
}

import org.springframework.beans.factory.FactoryBean;

public class CarFactoryBean implements FactoryBean<Car>{

    private String brand;
    
    public void setBrand(String brand) {
        this.brand = brand;
    }
    
    //返回bean的对象
    @Override
    public Car getObject() throws Exception {
        // TODO Auto-generated method stub
        return new Car(brand,50000);
    }

    //返回bean的类型
    @Override
    public Class<?> getObjectType() {
        // TODO Auto-generated method stub
        return Car.class;
    }

    @Override
    public boolean isSingleton() {
        // TODO Auto-generated method stub
        return true;
    }
}

<?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">
    <!-- 
        通过FactoryBean来配置bean的实例
        但实际返回的实例却是FactoryBean的getObject()方法返回的实例
     -->
    <bean id="car" class="com.auguigu.spring.beans.factoryBean.CarFactoryBean">
        <property name="brand" value="BWM"></property>
    </bean>
</beans>

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

public class Main {

    public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("beans-factoryBean.xml");
        Car car1 = (Car) ctx.getBean("car");
        System.out.println(car1);
        Car car2 = (Car) ctx.getBean("car");
        System.out.println(car1==car2);
        
    }
}

输出结果：

log4j:WARN No appenders could be found for logger (org.springframework.core.env.StandardEnvironment).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Car [name=BWM, price=50000.0]
true