[Spring] Beans Graph 확인 및 context 사용 [IoC(Inversion of Control) 실습하기]

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1. IoC(Inversion of Control)란?

'제어역행'이라 불리며, IoC가 적용되면 객체는 의존하는 다른 객체를 생성 및 찾는 대신 수동적으로 의존성을 받는다. 스프링 프레임워크는 제어역행(IoC)을 통해 애플리케이션의 느슨한 결합을 도모한다.

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2. IoC 실습하기

- ioc3.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 class="edu.blz.ioc3.Money" id="money">
		<property name="amount">
			<value>2000</value>
		</property>
	</bean>
	
	<bean class="edu.blz.ioc3.Car" id="car">
		<property name="name">
			<value>k7</value>
		</property>
	</bean>
	
	<bean class="edu.blz.ioc3.KiaMaker" id="kiaMaker">
		<property name="car">
			<ref bean="car" />
		</property>
	</bean>
	
	<bean class="edu.blz.ioc3.HyunDaiMaker" id="hyunDaiMaker">
		<property name="car">
			<bean class="edu.blz.ioc3.Car">
				<property name="name" value="sonata" />
			</bean>
		</property>
	</bean>
	
	<bean class="edu.blz.ioc3.DaewooMaker" id="daewooMaker">
		<property name="car">
			<bean class="edu.blz.ioc3.Car">
				<property name="name" value="tosca" />
			</bean>
		</property>
	</bean>
	
	<bean class="java.lang.String" id="tosca">
		<constructor-arg value="tosca" />
	</bean>
	
	<bean class="edu.blz.ioc3.OrderManager" id="orderManager">
		<property name="maker">
			<ref bean="hyunDaiMaker" />
		</property>
		<property name="money">
			<ref bean="money" />
		</property>
	</bean>
	
</beans>

 

ioc3의 Beans Graph

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- ioc4.xml(context 적용)

Spring Bean Configuration File 생성 시, 'context' 선택

 

<?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: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-3.2.xsd">

	<context:component-scan base-package="edu.blz.ioc4" />
</beans>

 

ioc4의 Beans Graph / context 사용

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3. IoC 실습 소스 코드

- Car.java

package edu.blz.ioc3;

public class Car {
	private String name;

	public Car() {
	}

	public Car(String name) {
		this.name = name;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}
}

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- CarMaker.java

package edu.blz.ioc3;

public interface CarMaker {
	Car sell(Money money);
}

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- DaewooMaker.java

package edu.blz.ioc3;

public class DaewooMaker implements CarMaker {
	private Car car;
	
	public void setCar(Car car) {
		this.car = car;
	}

	public Car sell(Money money) {
		return car;
	}
}

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- HyunDaiMaker.java

package edu.blz.ioc3;

public class HyunDaiMaker implements CarMaker {
	private Car car;
	
	public void setCar(Car car) {
		this.car = car;
	}

	public Car sell(Money money) {
		return car;
	}
}

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- KiaMaker.java

package edu.blz.ioc3;

public class KiaMaker implements CarMaker {
	private Car car;
	
	public void setCar(Car car) {
		this.car = car;
	}

	public Car sell(Money money) {
		return car;
	}
}

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- Money.java

package edu.blz.ioc3;

public class Money {
	private int amount;

	public Money() {
	}

	public Money(int amount) {
		this.amount = amount;
	}

	public int getAmount() {
		return amount;
	}

	public void setAmount(int amount) {
		this.amount = amount;
	}
}

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- OrderManager.java

package edu.blz.ioc3;

public class OrderManager {
	private CarMaker maker;
	private Money money;
	
	public void setMaker(CarMaker maker) {
		this.maker = maker;
	}

	public void setMoney(Money money) {
		this.money = money;
	}

	public void order() {
		Car car = maker.sell(money);
		System.out.println("I sold a car :: " + car.getName() + ", " + money.getAmount());
	}
}

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- OrderManagerApp.java

package edu.blz.ioc3;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class OrderManagerApp {
	public static void main(String[] args) {
		ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("ioc3.xml");
		OrderManager manager = ctx.getBean("orderManager", OrderManager.class);
		manager.order();
		ctx.close();
	}
}