component

@component 어노테이션을 사용하면 Bean Configuration 파일에 Bean을 등록하지 않아도 자동으로 등록된다.

@Component
public class TestBean3{

}

 

xml 이용방식

Bean에 설정된 설정들을 탐색하기 위해 다음과 같이 작성한다.

<context:component-scan base-package = "kr.co.softcampus.beans"/>
<context:component-scan base-package = "kr.co.softcampus.beans"/>

 

java 방식

Bean에 설정된 설정들을 탐색하기 위해 다음과 같이 작성한다.

@ComponentScan(basePackages = {"kr.co.softcampus.beans", "kr.co.softcampus.bean2})

 

xml을 이용하여 bean객체 생성

 

TestBean1 클래스

package kr.co.softcampus.beans;

public class TestBean1 {

}

 

TestBean2 클래스

package kr.co.softcampus.beans;

public class TestBean2 {

}

 

bean.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: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.xsd">
	                    
	
	<bean class='kr.co.softcampus.beans.TestBean1'/>
	<bean id='xml2' class='kr.co.softcampus.beans.TestBean2'/>

</beans>

 

main class

package kr.co.softcampus.main;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import kr.co.softcampus.beans.TestBean1;
import kr.co.softcampus.beans.TestBean2;
import kr.co.softcampus.beans2.TestBean3;
import kr.co.softcampus.beans2.TestBean4;
import kr.co.softcampus.beans3.TestBean5;
import kr.co.softcampus.config.BeanConfigClass;

public class MainClass {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		ClassPathXmlApplicationContext ctx1 = new ClassPathXmlApplicationContext("kr/co/softcampus/config/beans.xml");
		
		System.out.println("-------------------------------");
		
		TestBean1 xml1 = ctx1.getBean(TestBean1.class);
		System.out.printf("xml1 : %s\n", xml1);
		
		TestBean2 xml2 = ctx1.getBean("xml2", TestBean2.class);
		System.out.printf("xml2 : %s\n", xml2);
	
	}

}

 

java로 bean 객체생성

 

TestBean1클래스와 TestBean2클래스는 동일

 

BeanConfigClass

package kr.co.softcampus.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

import kr.co.softcampus.beans.TestBean1;
import kr.co.softcampus.beans.TestBean2;
import kr.co.softcampus.beans2.TestBean4;

@Configuration
public class BeanConfigClass {
	
	@Bean
	public TestBean1 java1() {
		return new TestBean1();
	}
	
	@Bean
	public TestBean2 java2() {
		return new TestBean2();
	}
	
}

 

main class

package kr.co.softcampus.main;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import kr.co.softcampus.beans.TestBean1;
import kr.co.softcampus.beans.TestBean2;
import kr.co.softcampus.beans2.TestBean3;
import kr.co.softcampus.beans2.TestBean4;
import kr.co.softcampus.beans3.TestBean5;
import kr.co.softcampus.config.BeanConfigClass;

public class MainClass {

	public static void main(String[] args) {
		// TODO Auto-generated method stub	
		AnnotationConfigApplicationContext ctx2 = new AnnotationConfigApplicationContext(BeanConfigClass.class);
		
		
		TestBean1 java1 = ctx2.getBean(TestBean1.class);
		System.out.printf("java1 : %s\n", java1);
		
		TestBean2 java2 = ctx2.getBean("java2", TestBean2.class);
		System.out.printf("java2 : %s\n", java2);
		
		ctx2.close();
	}

}

 

component 사용

 

클래스들은 kr.co.softcampus.bean2 패키지 안에 들어가잇다.

TestBean3 클래스

package kr.co.softcampus.beans2;

import org.springframework.stereotype.Component;

// Bean으로 등록한다.
// 이름이 없기 때문에 타입을 통해서 받아 낼수 있다.
@Component
public class TestBean3 {

}

 

TestBean4 클래스

package kr.co.softcampus.beans2;

import org.springframework.stereotype.Component;

@Component("bean4")
public class TestBean4 {

}

 

java 방식

 

BeanConfigClass

package kr.co.softcampus.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

import kr.co.softcampus.beans.TestBean1;
import kr.co.softcampus.beans.TestBean2;
import kr.co.softcampus.beans2.TestBean4;

@Configuration
// 지정된 패키지의 Bean 클래스들의 어노테이션을 분석하여 Bean을 등록하라고 지정한다.
@ComponentScan(basePackages = "kr.co.softcampus.beans2")
public class BeanConfigClass {
	
}

 

 

xml 방식

 

bean.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: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.xsd">
	                    
	<!-- 지정된 패키지 안에 있는 Bean 클래스들의 어노테이션을 분석하도록 지정한다 -->
	<context:component-scan base-package="kr.co.softcampus.beans2"/>
	
</beans>

main class

 

java 방식

package kr.co.softcampus.main;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import kr.co.softcampus.beans.TestBean1;
import kr.co.softcampus.beans.TestBean2;
import kr.co.softcampus.beans2.TestBean3;
import kr.co.softcampus.beans2.TestBean4;
import kr.co.softcampus.beans3.TestBean5;
import kr.co.softcampus.config.BeanConfigClass;

public class MainClass {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		AnnotationConfigApplicationContext ctx2 = new AnnotationConfigApplicationContext(BeanConfigClass.class);
		
		TestBean3 java4 = ctx2.getBean(TestBean3.class);
		System.out.printf("java4 : %s\n", java4);
		
		TestBean4 java5 = ctx2.getBean("bean4", TestBean4.class);
		System.out.printf("java5 : %s\n", java5);
		
		
		
		ctx2.close();
	}

}

 

xml 방식

package kr.co.softcampus.main;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import kr.co.softcampus.beans.TestBean1;
import kr.co.softcampus.beans.TestBean2;
import kr.co.softcampus.beans2.TestBean3;
import kr.co.softcampus.beans2.TestBean4;
import kr.co.softcampus.beans3.TestBean5;
import kr.co.softcampus.config.BeanConfigClass;

public class MainClass {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		ClassPathXmlApplicationContext ctx1 = new ClassPathXmlApplicationContext("kr/co/softcampus/config/beans.xml");

		TestBean3 xml4 = ctx1.getBean(TestBean3.class);
		System.out.printf("xml4 : %s\n", xml4);
		
		TestBean4 xml5 = ctx1.getBean("bean4", TestBean4.class);
		System.out.printf("xml5 : %s\n", xml5);
	
		ctx1.close();
	
	}

}

 

 

끝으로 Bean과 Component 활용 차이

 

Bean

개발자가 class의 코드를 수정할 수 없는 경우

같은 클래스 타입의 Bean을 여러 개 등록할 경우

 

Component

개발자가 class의 코드를 수정할 수 있는 경우