spring IOC

Posted 2021-02-02 mike_chang

IOC 概念

IOC即控制反转，其借鉴了工厂模式的思想，把实例化对象的代码抽取出来封装到一个地方统一管理。工厂模式是集中到工厂类里统一管理，spring是集中到xml配置文件里统一管理。

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 demo

package com.test.spring;
// 汉武帝
public class HanWudi {
    // 将军
    private General general;

    public HanWudi(General general) {
        this.general = general;
    }
    // order 命令
    public void order() {
        general.goToWar("楼兰");
    }
}

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package com.test.spring;
// 将军
public interface General {
    public void goToWar(String placeName); // 地方
}

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package com.test.spring;
// 霍去病
public class HuoQubing implements General {
    @Override
    public void goToWar(String placeName) {
        System.out.println("go to war with " + placeName);
    }
}

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<?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="king" class="com.test.spring.HanWudi">
        <constructor-arg ref="general"/>
    </bean>
    <bean id="general" class="com.test.spring.HuoQubing"></bean>
</beans>

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package com.test.spring;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Driver {
    private HanWudi hanWudi;

    public static void main(String[] args) {
        // my.xml放在maven项目的resources目录下
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("/my.xml");
        HanWudi hanWudi = context.getBean(HanWudi.class);
        hanWudi.order();
        context.close();
    }
}

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