[Spring] Error creating bean with name 'jwtUtil': Injection of autowired dependencies failed, Could not resolve placeholder 'jwt.secret.key' in value "${jwt.secret.key}" 해결하기

<상황>

Spring Boot 환경에서 JWT 라이브러리를 설정하고, JWT Util 클래스를 구현한 뒤 토큰 생성 기능을 테스트하기 위해 실행을 눌렀는데, 아래와 같은 에러가 발생했다.

Error starting ApplicationContext. To display the condition evaluation report re-run your application with 'debug' enabled.
2026-01-21T15:02:24.048+09:00 ERROR 4420 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jwtUtil': Injection of autowired dependencies failed
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:498) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1446) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:602) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:525) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:333) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:371) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:331) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:196) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.instantiateSingleton(DefaultListableBeanFactory.java:1218) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingleton(DefaultListableBeanFactory.java:1184) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:1121) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:993) ~[spring-context-7.0.2.jar:7.0.2]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:620) ~[spring-context-7.0.2.jar:7.0.2]
at org.springframework.boot.web.server.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:143) ~[spring-boot-web-server-4.0.1.jar:4.0.1]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:756) ~[spring-boot-4.0.1.jar:4.0.1]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:445) ~[spring-boot-4.0.1.jar:4.0.1]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:321) ~[spring-boot-4.0.1.jar:4.0.1]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1365) ~[spring-boot-4.0.1.jar:4.0.1]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1354) ~[spring-boot-4.0.1.jar:4.0.1]
at cohttp://m.example.advance11.Advance11Application.main(Advance11Application.java:10) ~[main/:na]
Caused by: org.springframework.util.PlaceholderResolutionException: Could not resolve placeholder 'jwt.secret.key' in value "${jwt.secret.key}"
at org.springframework.util.PlaceholderResolutionException.withValue(PlaceholderResolutionException.java:81) ~[spring-core-7.0.2.jar:7.0.2]
at org.springframework.util.PlaceholderParser$ParsedValue.resolve(PlaceholderParser.java:296) ~[spring-core-7.0.2.jar:7.0.2]
at org.springframework.util.PlaceholderParser.replacePlaceholders(PlaceholderParser.java:129) ~[spring-core-7.0.2.jar:7.0.2]
at org.springframework.util.PropertyPlaceholderHelper.replacePlaceholders(PropertyPlaceholderHelper.java:96) ~[spring-core-7.0.2.jar:7.0.2]
at org.springframework.core.env.AbstractPropertyResolver.doResolvePlaceholders(AbstractPropertyResolver.java:286) ~[spring-core-7.0.2.jar:7.0.2]
at org.springframework.core.env.AbstractPropertyResolver.resolveRequiredPlaceholders(AbstractPropertyResolver.java:257) ~[spring-core-7.0.2.jar:7.0.2]
at org.springframework.context.support.PropertySourcesPlaceholderConfigurer.lambda$processProperties$0(PropertySourcesPlaceholderConfigurer.java:184) ~[spring-context-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.support.AbstractBeanFactory.resolveEmbeddedValue(AbstractBeanFactory.java:959) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1672) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1651) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.resolveFieldValue(AutowiredAnnotationBeanPostProcessor.java:763) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:747) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:146) ~[spring-beans-7.0.2.jar:7.0.2]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:492) ~[spring-beans-7.0.2.jar:7.0.2]
... 19 common frames omitted

<해결>

 

일단 크게 두 개가 눈에 들어온다.

 

1. 어떤 상황인지 - jwtUtil이라는 이름의 bean을 등록하는 과정에서 에러가 발생한 것 같다.

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jwtUtil': Injection of autowired dependencies failed

 

2. 원인은 무엇인지 - jwt.secret.key라는 placeholder를 이해할 수 없다는 것 같다. Caused by: org.springframework.util.PlaceholderResolutionException: Could not resolve placeholder 'jwt.secret.key' in value "${jwt.secret.key}"

 

찾아보니 jwt 설정이 맨 왼쪽부터가 아닌 spring: 아래에 들여쓰기가 되어 있어 프로퍼티 키가 우리가 의도했던 jwt.secret.key가 아니라 spring.jwt.secret.key로 되었던 것이었다.

 

특히 yaml은 띄어쓰기에 매우 민감하다고 한다. 탭(tab)도 안 되고 정확히 스페이스 2칸으로 해야 한다고 하니, 이 점을 주의하도록 하자.

 

<결론>

 

yaml 파일은 들여쓰기를 조심해야 한다