swagger3.0 에러 발생 Failed to start bean 'documentationPluginsBootstrapper'

swagger3.0 에러 발생 Failed to start bean 'documentationPluginsBootstrapper'

Swagger를 적용하기 위해 build.gradle 에 dependencies에 추가

SwaggerConfig.java

문제 : Swagger 설정을 끝마쳤으나 아래와 같은 에러가 계속 발생

022-05-30 13:08:12.976 ERROR 376352 --- [  restartedMain] o.s.boot.SpringApplication               : Application run failed
org.springframework.context.ApplicationContextException: Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException
at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:181) ~[spring-context-5.3.19.jar:5.3.19]
at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:54) ~[spring-context-5.3.19.jar:5.3.19]
at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:356) ~[spring-context-5.3.19.jar:5.3.19]
at java.lang.Iterable.forEach(Iterable.java:75) ~[na:1.8.0_241]
at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:155) ~[spring-context-5.3.19.jar:5.3.19]
at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:123) ~[spring-context-5.3.19.jar:5.3.19]
at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:935) ~[spring-context-5.3.19.jar:5.3.19]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:586) ~[spring-context-5.3.19.jar:5.3.19]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.6.7.jar:2.6.7]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:740) [spring-boot-2.6.7.jar:2.6.7]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:415) [spring-boot-2.6.7.jar:2.6.7]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) [spring-boot-2.6.7.jar:2.6.7]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1312) [spring-boot-2.6.7.jar:2.6.7]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1301) [spring-boot-2.6.7.jar:2.6.7]
at com.ynkim.restfulwebservice.RestfulWebServiceApplication.main(RestfulWebServiceApplication.java:14) [main/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_241]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_241]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_241]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_241]
at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-2.6.7.jar:2.6.7]
Caused by: java.lang.NullPointerException: null
at springfox.documentation.spring.web.WebMvcPatternsRequestConditionWrapper.getPatterns(WebMvcPatternsRequestConditionWrapper.java:56) ~[springfox-spring-webmvc-3.0.0.jar:3.0.0]
at springfox.documentation.RequestHandler.sortedPaths(RequestHandler.java:113) ~[springfox-core-3.0.0.jar:3.0.0]
at springfox.documentation.spi.service.contexts.Orderings.lambda$byPatternsCondition$3(Orderings.java:89) ~[springfox-spi-3.0.0.jar:3.0.0]
at java.util.Comparator.lambda$comparing$77a9974f$1(Comparator.java:469) ~[na:1.8.0_241]
at java.util.TimSort.countRunAndMakeAscending(TimSort.java:355) ~[na:1.8.0_241]
at java.util.TimSort.sort(TimSort.java:220) ~[na:1.8.0_241]
at java.util.Arrays.sort(Arrays.java:1512) ~[na:1.8.0_241]
at java.util.ArrayList.sort(ArrayList.java:1462) ~[na:1.8.0_241]
at java.util.stream.SortedOps$RefSortingSink.end(SortedOps.java:387) ~[na:1.8.0_241]
at java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[na:1.8.0_241]
at java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[na:1.8.0_241]
at java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[na:1.8.0_241]
at java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[na:1.8.0_241]
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:483) ~[na:1.8.0_241]
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472) ~[na:1.8.0_241]
at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708) ~[na:1.8.0_241]
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:1.8.0_241]
at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499) ~[na:1.8.0_241]
at springfox.documentation.spring.web.plugins.WebMvcRequestHandlerProvider.requestHandlers(WebMvcRequestHandlerProvider.java:81) ~[springfox-spring-webmvc-3.0.0.jar:3.0.0]
at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) ~[na:1.8.0_241]
at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1382) ~[na:1.8.0_241]
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482) ~[na:1.8.0_241]
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472) ~[na:1.8.0_241]
at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708) ~[na:1.8.0_241]
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:1.8.0_241]
at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499) ~[na:1.8.0_241]
at springfox.documentation.spring.web.plugins.AbstractDocumentationPluginsBootstrapper.withDefaults(AbstractDocumentationPluginsBootstrapper.java:107) ~[springfox-spring-web-3.0.0.jar:3.0.0]
at springfox.documentation.spring.web.plugins.AbstractDocumentationPluginsBootstrapper.buildContext(AbstractDocumentationPluginsBootstrapper.java:91) ~[springfox-spring-web-3.0.0.jar:3.0.0]
at springfox.documentation.spring.web.plugins.AbstractDocumentationPluginsBootstrapper.bootstrapDocumentationPlugins(AbstractDocumentationPluginsBootstrapper.java:82) ~[springfox-spring-web-3.0.0.jar:3.0.0]
at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.start(DocumentationPluginsBootstrapper.java:100) ~[springfox-spring-web-3.0.0.jar:3.0.0]
at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:178) ~[spring-context-5.3.19.jar:5.3.19]
... 19 common frames omitted

 

해결방법 1 

Spring boot 2.6.2버전 이후 sping.mvc.pathmatch.matching-strategy 의 값이
ant_path_matcher -> path_pattern_parser로 변경되면서 라이브러리(swagger포함)내부에 오류가 발생함.

application.yml 파일에 아래 와 같이 추가 한다.

spring:
  mvc:
    pathmatch:
      matching-strategy: ant_path_matcher

해결방법 2

 spring-boot 의 버전을 2.5.x 버전으로 낮추는 방법