spring bean 静态工厂实例化

痛定思痛。 2024-02-19 12:18 74阅读 0赞

spring bean 静态工厂实例化

在工厂类中创建一个静态方法来实例化对象。在配置bean时，class指定静态工厂类，同时还需要使用factory-method属性指定工厂类中的静态方法。

1.创建工厂类BeanStaticFactory

![70][]

package instance;
    
    public class BeanStaticFactory {
    	private static BeanClass beanInstance = new BeanClass("调用静态工厂方法实例化bean");
    	public static BeanClass createInstance() {
    		return beanInstance;
    	}
    }

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">
            
        </bean>
        
        
    	<bean id="staticFacoryInstance" class="instance.BeanStaticFactory" factory-method="createInstance">
    	
    	</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);
    	}
    }

![70 1][]

[70]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/3a91510a7cb94a749ec2b73522991089.png
[70 1]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/2322daf304754c298cef576f615cacc3.png