Spring中的＜lookup-method＞标签的功能简介说明

一、<lookup-method/>标签的功能

 使用spring注入
   将“多例bean”替换抽象类的方法

 
// 定义一个水果类
public class Fruit {
    public Fruit() {
        System.out.println("I got Fruit");
    }
}

// 苹果
public class Apple extends Fruit {
    public Apple() {
        System.out.println("I got a fresh apple");
    }
}

// 香蕉
public class Bananer extends Fruit {
    public Bananer () {
        System.out.println("I got a  fresh bananer");
    }
}

// 水果盘，可以拿到水果
public abstract class FruitPlate{
    // 抽象方法获取新鲜水果
    protected abstract Fruit getFruit();
}
 
spring配置：

<!-- 这是2个非单例模式的bean -->
<bean id="apple" class="cn.com.willchen.test.di.Apple" scope="prototype"/>
<bean id="bananer" class="cn.com.willchen.test.di.Bananer " scope="prototype"/>
<bean id="fruitPlate1" class="cn.com.willchen.test.di.FruitPlate">
    <lookup-method name="getFruit" bean="apple"/>
</bean>
<bean id="fruitPlate2" class="cn.com.willchen.test.di.FruitPlate">
    <lookup-method name="getFruit" bean="bananer"/>
</bean>
 
测试代码
public static void main(String[] args) {
    ApplicationContext app = new ClassPathXmlApplicationContext("classpath:resource/applicationContext.xml");

    FruitPlate fp1= (FruitPlate)app.getBean("fruitPlate1");
    FruitPlate fp2 = (FruitPlate)app.getBean("fruitPlate2");

    fp1.getFruit();
    fp2.getFruit();
}