Spring通过工厂方法创建对象

﹏ヽ暗。殇╰゛Y 2022-05-09 05:20 184阅读 0赞

## 静态工厂 ##

工厂类

public class AppleFactory {
    	public static Apple newInstance(String color) {
    		return new Apple(color);
    	}
    }

xml

<?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="AppleFactory" class="cn.lee.factory.AppleFactory" factory-method="newInstance">
    		        	<constructor-arg index="0" value="red"></constructor-arg>
    		</bean>
    		
    </beans>

测试代码

ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");	
    Apple hongFuShi = (Apple)context.getBean("AppleFactory");
    System.out.println(hongFuShi.getColor());

输出

red

## 动态工厂 ##

工厂类（与静态工厂相比只是少了static）

public class DynamicAppleFactory {
    	public Apple newInstance(String color) {
    		return new Apple(color);
    	}
    }

xml

<?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="dynamicAppleFactory" class="cn.lee.factory.DynamicAppleFactory"></bean>
           <bean id="Apple" factory-bean="dynamicAppleFactory" factory-method="newInstance">
           		<constructor-arg value="red"></constructor-arg>  
            </bean>
            
    </beans>

测试代码

ApplicationContext context = new ClassPathXmlApplicationContext("beans2.xml");		
    Apple hongFuShi = (Apple)context.getBean("Apple");
    System.out.println(hongFuShi.getColor());

输出

red