[Trouble Shooting] Spring에서 Swagger 설정을 위한 Dependency 추가

Problem

Swagger사용을 위해 pom.xml 파일을 추가하던 중 아래와 같은 에러가 발생했다.

 

org.springframework.context.ApplicationContextException: Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException: Cannot invoke "org.springframework.web.servlet.mvc.condition.PatternsRequestCondition.getPatterns()" because "this.condition" is null

2022-01-14 23:04:12.782  INFO 28998 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2022-01-14 23:04:12.790 ERROR 28998 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.context.ApplicationContextException: Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException: Cannot invoke "org.springframework.web.servlet.mvc.condition.PatternsRequestCondition.getPatterns()" because "this.condition" is null
	at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:181) ~[spring-context-5.3.14.jar:5.3.14]
	at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:54) ~[spring-context-5.3.14.jar:5.3.14]
	at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:356) ~[spring-context-5.3.14.jar:5.3.14]
	at java.base/java.lang.Iterable.forEach(Iterable.java:75) ~[na:na]
	at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:155) ~[spring-context-5.3.14.jar:5.3.14]
	at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:123) ~[spring-context-5.3.14.jar:5.3.14]
	at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:935) ~[spring-context-5.3.14.jar:5.3.14]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:586) ~[spring-context-5.3.14.jar:5.3.14]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.6.2.jar:2.6.2]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:730) ~[spring-boot-2.6.2.jar:2.6.2]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:412) ~[spring-boot-2.6.2.jar:2.6.2]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:302) ~[spring-boot-2.6.2.jar:2.6.2]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1301) ~[spring-boot-2.6.2.jar:2.6.2]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1290) ~[spring-boot-2.6.2.jar:2.6.2]
	at kakaopaysec.assignment1.Assignment1Application.main(Assignment1Application.java:10) ~[classes/:na]

정확히 뭐가 문제였는지는 모르겠지만, 여기저기 검색해보니 Spring과 Swagger의 버전이 맞지 않으면 발생할 수 있는 문제라 했다.

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Solution

그래서 기존 세팅에는 아래처럼 Spring 2.6.2, Swagger 3.0.0 버전이었으나

아래와 같이 Parent 부분은 2.4.0, swagger는 2.9.2로 변경하니 정상적으로 작동하였다.

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.4.0</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

/*중략*/

<!-- swagger사용을 위한 Dependency 추가 -->
<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-swagger-ui</artifactId>
    <version>2.9.2</version>
</dependency>
<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-swagger2</artifactId>
    <version>2.9.2</version>
</dependency>

 

위와 같이 수정하기 전에, swagger 설정을 위해 여러 글들을 참고하며 아래 dependency도 추가했었는데

2.9.2 버전으로 설정하니 import가 되지 않아 삭제했다

<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-boot-starter</artifactId>
    <version>3.0.0</version>
</dependency>

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참고

https://ldne.tistory.com/332