Inflearn Community Q&A

hyunybutterchip

asked

Spring Core Principles - Basic Edition

Option Processing

NoUniqueBeanDefinitionException 에러

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Caused by: org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'hello.core.discount.DiscountPolicy' available: expected single matching bean but found 2: rateDiscountPolicy,getDiscountPolicy

이 에러가 나서 원인을 찾아보니 AppConfig의

@Bean
public DiscountPolicy getDiscountPolicy() {
    //return new FixDiscountPolicy();
    return new RateDiscountPolicy();
}

이 부분과

@Component
public class RateDiscountPolicy implements DiscountPolicy {}

이 부분때문에 RateDiscountPolicy 빈이 2개로 등록되어서 그런 것 같아 AppConfig에서 @Bean어노테이션을 주석처리하니 정상적으로 테스트가 됐는데요.

궁금한 점은 AutoAppConfig 에서 AppConfig에 대한 부분은 제외를 시켰는데 왜 중복이 되는가입니다....

@Configuration
@ComponentScan(
        basePackages = "hello.core.member",
        excludeFilters = @ComponentScan.Filter(type = FilterType.ANNOTATION, classes = Configuration.class)
) // 기존 AppConfig.java 때문에 컴포넌트 스캔 대상에서 제외시킴
public class AutoAppConfig {}

객체지향oopspring

Quiz

What are the main reasons why Field Injection is generally not recommended?

Because it is difficult to guarantee immutability

Because changing dependencies is easy

Because it's difficult to test with pure Java code

Because writing configuration code is complex

Answer 3