스프링 프레임 워크 시작하기 - bean추가

 

beans.xml 에 bean 추가하기 

<?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">

	<!-- 해당 클래스로 만든 객체 hello를 스프링에 등록 -->
	<bean id="hello" class="com.demo.beans.HelloWorldEn" />
</beans>

 

 

 

비교하기에서 만든 demo.beans 패키지 복사해서 넣어주고 이름 바꾸기

 

 

main 클래스로 이동해서 실행하면 

12:06:53.788 [main] DEBUG org.springframework.context.support.ClassPathXmlApplicationContext - Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@32d2fa64
12:06:53.931 [main] DEBUG org.springframework.beans.factory.xml.XmlBeanDefinitionReader - Loaded 1 bean definitions from class path resource [com/demo/config/beans.xml]
12:06:53.951 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'hello'
12:06:53.980 [main] DEBUG org.springframework.context.support.ClassPathXmlApplicationContext - Closing org.springframework.context.support.ClassPathXmlApplicationContext@32d2fa64, started on Wed Oct 18 12:06:53 KST 2023

 

singleton 클래스로 하나의 객체를 만든다. 

 

 

 

main에서 beans 사용하기 

 

package com.demo.main;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.demo.beans.HelloWorld;

public class MainClass {

	public static void main(String[] args) {
		// beans.xml 파일을 로딩한다
		ClassPathXmlApplicationContext ctx = 
				new ClassPathXmlApplicationContext("com/demo/config/beans.xml");
		
		//xml에 정의된 beans 객체의 주소값을 가져온다. 
		//bean 이름이 hello임 (id값) 타입은 object로 리턴되기 때문에 타입 설정이 필요함 
		//그래서 (HelloWorld) 붙여줌 
		HelloWorld hello1 = (HelloWorld)ctx.getBean("hello");
		callMethod(hello1);
		
		ctx.close();

	}
	
	
	public static void callMethod(HelloWorld hello) {
		hello.sayHello();
	}

}

 

 

실행 결과 (Hello) 출력확인 

12:11:58.533 [main] DEBUG org.springframework.context.support.ClassPathXmlApplicationContext - Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@32d2fa64
12:11:58.674 [main] DEBUG org.springframework.beans.factory.xml.XmlBeanDefinitionReader - Loaded 1 bean definitions from class path resource [com/demo/config/beans.xml]
12:11:58.694 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'hello'
Hello
12:11:58.723 [main] DEBUG org.springframework.context.support.ClassPathXmlApplicationContext - Closing org.springframework.context.support.ClassPathXmlApplicationContext@32d2fa64, started on Wed Oct 18 12:11:58 KST 2023

 

 

객체를 스프링에 등록만 시켜주면 스프링에서 자동으로 객체를 가져와서  사용을 할 수 있음. 

 

 

		//타입 설정 첫 번째 방법
		HelloWorld hello1 = (HelloWorld)ctx.getBean("hello");
		callMethod(hello1);
		
		
		//타입 설정 두 번째 방법
		HelloWorld hello2 = ctx.getBean("hello",HelloWorld.class);	
		callMethod(hello2);

 

 

 

 

이번에는 ko 객체 만들기 

beans.xml  -> 기존 en 은 주석처리하고 ko추가 

<?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">


	<!-- 해당 클래스로 만든 객체 hello를 스프링에 등록 -->
	<!-- <bean id="hello" class="com.demo.beans.HelloWorldEn" /> -->
	<bean id="hello" class="com.demo.beans.HelloWorldKo" />
</beans>

 

 

main에 와서 

실행 결과 (안녕하세요) 출력확인

12:16:57.499 [main] DEBUG org.springframework.context.support.ClassPathXmlApplicationContext - Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@32d2fa64
12:16:57.640 [main] DEBUG org.springframework.beans.factory.xml.XmlBeanDefinitionReader - Loaded 1 bean definitions from class path resource [com/demo/config/beans.xml]
12:16:57.661 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'hello'
안녕하세요
안녕하세요
12:16:57.689 [main] DEBUG org.springframework.context.support.ClassPathXmlApplicationContext - Closing org.springframework.context.support.ClassPathXmlApplicationContext@32d2fa64, started on Wed Oct 18 12:16:57 KST 2023

 

 

현재 이 방법은 원리를 알기위해서 하는 방법이고 이후에는

bean 등록만하면 자동으로 변경되게끔 사용가능함