Bean配置檔案

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:p="http://www.springframework.org/schema/p"
	xmlns:util="http://www.springframework.org/schema/util"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
		http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.3.xsd">
		
	<!-- 通過實現FactoryBean介面 配置bean -->
	<bean id="cola" class="top.demo.test.spring2.WaterFactoryBean"></bean>
	
	
</beans>

 

測試用到的Water類

package top.demo.test.spring2;

public class Water {

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

 

實現FactoryBean的類

package top.demo.test.spring2;

import org.springframework.beans.factory.FactoryBean;

public class WaterFactoryBean implements FactoryBean<Water>{

	@Override
	public Water getObject() throws Exception {
		//獲得工廠建立的物件的介面方法
		return new Water("可樂", 4);
	}

	@Override
	public Class<?> getObjectType() {
		// 返回物件的Class
		return Water.class;
	}

	
	@Override
	public boolean isSingleton() {
		// 返回是否是單例的
		//注意這個方法，如果返回true代表單例，即使getObject方法實現時是new（好像是每次呼叫會有新的地址，但是不是）
//也會得到同一個地址的物件（也就是 是不是單例取決於isSingleton方法，不必奇怪，有反射和動態代理 //框架設計者完全可以做到在getObject之前 檢查isSingleton 也可以儲存第一次new 出的地址 ）
		return true;
	}


}

 

測試main

package top.demo.test.spring2;

import java.util.Arrays;
import java.util.List;

import org.springframework.beans.factory.FactoryBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Main {
	
	
	public static void main(String argv[]) {
		
		ApplicationContext ctx=new ClassPathXmlApplicationContext("applicationContext2.xml");
		
		Water cola=(Water) ctx.getBean("cola");
		System.out.println(cola);
		
	}
	
}