ComponentScan

package hello.core;

import hello.core.member.MemberRepository;
import hello.core.member.MemoryMemberRepository;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;

@Configuration
//@Component가 붙은 모든 클래스를 자동으로 스프링 빈으로 듣록해줌.
@ComponentScan(
        //hello.core 패키지부터 하위로 컴포넌트 스캔을 하는 것.
        basePackages = "hello.core",

        //AutoAppConfig.class가 있는 패키지부터 스캔을 하는 것.
        basePackageClasses = AutoAppConfig.class,

        //기존의 AppConfig.java와 충돌이 날까봐 스캔을 제외하는 코드
        excludeFilters = @ComponentScan.Filter(
                type = FilterType.ANNOTATION, classes = Configuration.class))
public class AutoAppConfig {
}
// AutoAppConfig.java


@Component
public class MemberServiceImpl implements MemberService {

    private final MemberRepository memberRepository;

    @Autowired
    public MemberServiceImpl(MemberRepository memberRepository) {
        this.memberRepository = memberRepository;
    }
}


@Component
public class MemoryMemberRepository implements MemberRepository{

@Component
public class OrderServiceImpl implements OrderService{

    private final MemberRepository memberRepository;
    private final DiscountPolicy discountPolicy;

    @Autowired
    public OrderServiceImpl(MemberRepository memberRepository, DiscountPolicy discountPolicy) {
        this.memberRepository = memberRepository;
        this.discountPolicy = discountPolicy;
    }
}


@Component
public class RateDiscountPolicy implements DiscountPolicy{

package hello.core.scan;

import hello.core.AutoAppConfig;
import hello.core.member.MemberService;
import org.junit.jupiter.api.Test;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

import static org.assertj.core.api.Assertions.*;

public class AutoAppConfigTest {

    @Test
    void basicScan(){
        AnnotationConfigApplicationContext ac 
                = new AnnotationConfigApplicationContext(AutoAppConfig.class);

        MemberService memberService = ac.getBean(MemberService.class);

        assertThat(memberService).isInstanceOf(MemberService.class);

    }
}
//AutoAppConfigTest.java

package hello.core.scan.filter;

import java.lang.annotation.*;

//@Component에 들어가서 있는 애노테이션 복사해오기
//Target이 가장 중요. Type은 클래스 레벨에 붙는 것.
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented

//이 애노테이션 붙은건 컴포넌트 스캔에 추가
public @interface MyIncludeComponent {
}
//MyIncludeComponent.java

package hello.core.scan.filter;

import java.lang.annotation.*;

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented

//이 애노테이션이 붙은건 컴포넌트 스캔에서 제외
public @interface MyExcludeComponent {
}
//MyExcludeComponent.java

package hello.core.scan.filter;

@MyIncludeComponent
public class BeanA {
}
//BeanA.java

package hello.core.scan.filter;

@MyExcludeComponent
public class BeanB {
}
//BeanB.java

package hello.core.scan.filter;

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;

import static org.assertj.core.api.Assertions.*;
import static org.junit.jupiter.api.Assertions.*;

public class ComponentFilterAppConfigTest {

    @Configuration
    @ComponentScan(
            //타입이 ANNOTATION이 디폴트여서 생략도 가능.
            includeFilters = @ComponentScan.Filter(classes = MyIncludeComponent.class),

            excludeFilters = @ComponentScan.Filter(
                    type = FilterType.ANNOTATION, classes = MyExcludeComponent.class)
    )

    static class ComponentAppConfig{
    }

    @Test
    void filterScan(){
        AnnotationConfigApplicationContext ac 
                = new AnnotationConfigApplicationContext(ComponentAppConfig.class);

        //beanA는 Null이면 안되고 조회가 되어야 함.
        BeanA beanA = ac.getBean("beanA", BeanA.class);
        assertThat(beanA).isNotNull();

        //beanB는 조회가 되면 안되고 exception이 터져야함.
        //BeanB beanB = ac.getBean("beanB", BeanB.class);
        assertThrows(NoSuchBeanDefinitionException.class,
                () -> ac.getBean("beanB", BeanB.class));

    }
}
//ComponentFilterAppConfigTest.java

public class AutoAppConfig {

    //수동/자동 중복 등록 충돌을 확인하기 위한 코드
    @Bean(name="memoryMemberRepository")
    MemberRepository memberRepository(){
        return new MemoryMemberRepository();
    }
}
//AutoAppConfig.java