Spring WebFlux 사용시 InvalidDefinitionException 처리 방법

start.spring.io에서 WebFlux를 다운로드 받아서 기본적인 세팅을 하고 실행하는데 아래 에러가 나온다. 그래서 검색해보니 web과 webflux 모듈이 충돌이 나는듯 하다. 그래서 해결책은 web 제거! 끝.

 

에러: 

com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of `reactor.core.publisher.Mono` (no Creators, like default constructor, exist): abstract types either need to be mapped to concrete types, have custom deserializer, or contain additional type information
 at [Source: (PushbackInputStream); line: 1, column: 1]
 	at com.fasterxml.jackson.databind.exc.InvalidDefinitionException.from(InvalidDefinitionException.java:67) ~[jackson-databind-2.11.3.jar:2.11.3]
	at com.fasterxml.jackson.databind.DeserializationContext.reportBadDefinition(DeserializationContext.java:1615) ~[jackson-databind-2.11.3.jar:2.11.3]
	at com.fasterxml.jackson.databind.DatabindContext.reportBadDefinition(DatabindContext.java:400) ~[jackson-databind-2.11.3.jar:2.11.3]
	at com.fasterxml.jackson.databind.DeserializationContext.handleMissingInstantiator(DeserializationContext.java:1077) ~[jackson-databind-2.11.3.jar:2.11.3]
	at com.fasterxml.jackson.databind.deser.AbstractDeserializer.deserialize(AbstractDeserializer.java:265) ~[jackson-databind-2.11.3.jar:2.11.3]
	at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4526) ~[jackson-databind-2.11.3.jar:2.11.3]
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3521) ~[jackson-databind-2.11.3.jar:2.11.3]
	at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:274) ~[spring-web-5.3.1.jar:5.3.1]
	at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.read(AbstractJackson2HttpMessageConverter.java:243) ~[spring-web-5.3.1.jar:5.3.1]
    .....

 

해결책

build.gradle에서 spring-boot-starter-web을 제거해라.

implementation("org.springframework.boot:spring-boot-starter-web")

 

Best Regards

Hans