Spring通过不同的工厂创建对象

结构图

代码

GoodsBIZ.java

package com.biz;

import com.dao.GoodsDao;

public class GoodsBIZ {
    private GoodsDao goodsDao;

    public GoodsDao getGoodsDao() {
        return goodsDao;
    }

    public void setGoodsDao(GoodsDao goodsDao) {
        this.goodsDao = goodsDao;
    }
    public void save(){
        System.out.println("GoodsBIZ.save() is called…");
        this.goodsDao.save();
    }
}

GoodsController.java

package com.controller;

import com.biz.GoodsBIZ;

public class GoodsController {
    private GoodsBIZ goodsBIZ;
    public GoodsController(GoodsBIZ goodsBIZ){
        System.out.println("GoodsController的有参构造被调用");
        this.goodsBIZ = goodsBIZ;
    }

    public void save(){
        System.out.println("GoodsController.save() is called…");
        goodsBIZ.save();
    }
}
[/sourcecode]
        [sourcecode language=”java” title=”com.dao.GoodsDao.java”]
        package com.dao;

public interface GoodsDao {
    public void save();
}

GoodsDaoImpl.java

package com.dao.impl;

import com.dao.GoodsDao;

public class GoodsDaoImpl implements GoodsDao {

    @Override
    public void save() {
        System.out.println("GoodsDaoImpl.save() is called…");
    }
}

DaoFactory.java

package com.factory;

import com.dao.GoodsDao;
import com.dao.impl.GoodsDaoImpl;

public class DaoFactory {
    public static GoodsDao createDao(){
        return new GoodsDaoImpl();
    }
    public GoodsDao getDao(){
        return new GoodsDaoImpl();
    }
}

applicationContext.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"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.1.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd">

<bean name="goodsDao" class="com.dao.impl.GoodsDaoImpl"/>

<bean name="goodsBIZ" class="com.biz.GoodsBIZ">
<property name="goodsDao"> <!– GoodsBIZA有个属性叫goodsDAO –>
<ref bean="goodsDao"/> <!–依赖。引用了上面那个bean(1) –>
</property>
</bean>

<bean name="goodsController" class="com.controller.GoodsController">
<constructor-arg name="goodsBIZ" ref="goodsBIZ"/>
</bean>

<bean name="dao1" class="com.factory.DaoFactory" factory-method="createDao"/>

<bean name="daoFactory" class="com.factory.DaoFactory"/>
<bean name="dao2" factory-bean="daoFactory" factory-method="getDao" scope="prototype"/>
<!– scope属性默认为”singleton”,表示单例；取prototype代表多例 –>
</beans>

SpringTest.java

package com.test;

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

import com.biz.GoodsBIZ;
import com.controller.GoodsController;
import com.dao.GoodsDao;

public class SpringTest {

    public static void main(String[] args) {

        @SuppressWarnings("resource")
        ApplicationContext context =
                new ClassPathXmlApplicationContext("/applicationContext.xml");

//注释掉的是不同的方法创建出的对象

/*GoodsDao goodsDao = (GoodsDao) context.getBean("goodsDao");
goodsDao.save();*/

/*GoodsBIZ goodsBIZ = (GoodsBIZ) context.getBean("goodsBIZ");
goodsBIZ.save();*/

/*GoodsController goodsController = (GoodsController) context.getBean("goodsController");
goodsController.save();*/

/*GoodsDao dao1 = (GoodsDao) context.getBean("dao1");
System.out.println(dao1);*/

        GoodsDao dao21 = (GoodsDao) context.getBean("dao2");
        System.out.println(dao21);
        GoodsDao dao22 = (GoodsDao) context.getBean("dao2");
        System.out.println(dao22);
        System.out.println(dao21 == dao22);
    }

}