spring bean 实例工厂实例化

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spring bean 实例工厂实例化

在工厂类中创建一个实例方法来实例化对象。在配置bean时需要使用factory-bean属性指定配置的实例工厂，同时还需要使用factory-method属性指定实例工厂中的实例方法

1.创建工厂类BeanInstanceFactory

package instance;

public class BeanInstanceFactory {
	public BeanClass createBeanClassInstance() {
		return new BeanClass("调用实例工厂方法实例化bean");
	}
}

2.编辑配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="constructorInstance" class="instance.BeanClass">
        <!-- collaborators and configuration for this bean go here -->
    </bean>
    
    <!-- 静态工厂实例化bean  -->
	<bean id="staticFacoryInstance" class="instance.BeanStaticFactory" factory-method="createInstance">
	
	</bean>
	
	<!-- 配置工厂 -->
    <bean id="myFactory" class="instance.BeanInstanceFactory">
    </bean>
    <!-- 实例工厂实例化bean  -->
    <bean id="instanceFacoryInstance" factory-bean="myFactory" factory-method="createBeanClassInstance">
    </bean>
    
</beans>

3.添加测试代码

package test;

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

import instance.BeanClass;

public class TestInstance {
	public static void main(String[] args) {
		ApplicationContext appCon = new ClassPathXmlApplicationContext("applicationContext.xml");
		
		BeanClass b1 = (BeanClass)appCon.getBean("constructorInstance");
		System.out.println(b1+b1.message);
		
		//测试静态工厂实例化bean
		BeanClass b2 =(BeanClass)appCon.getBean("staticFacoryInstance");
		System.out.println(b2+b2.message);
		
		//测试实例广场实例化bean
		BeanClass b3 =(BeanClass)appCon.getBean("instanceFacoryInstance");
		System.out.println(b3+b3.message);
	}
}