어노테이션 만들기(@Qualifier)

@Qualifiler("mainDiscountPolicy") 이렇게 문자를 적으면 컴파일시 타입 체크가 안된다. 다음과 같은 어노테이션을 만들어서 문제를 해결할 수있다.

package hello.core.annotaion;

import org.springframework.beans.factory.annotation.Qualifier;
import java.lang.annotaion.*;

@Target({ElmentType.FIELD,ElementType.METHOD, ElementType.PARAMETER, ElementType.TYPE,
ElementType.ANNOTATION.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Qualifier("mainDiscountPolicy")
public @Interface MainDiscountPolicy{}

@Component
@MainDiscountPolicy
public class RateDiscountPolicy implements DiscountPolicy{}

@Autowired
public OrderServiceImpl(MemberRepository memeberRepository,
						@MainDiscountPolicy DiscountPlicy discountPolicy{
      this.memberRepostiory = memberRepositoyr;
      this.discountPolicy = discountPolicy;
                        
      }