来自 openfeign 和 Observable 的 @FeignClient 导致 fasterxml.jackson.databind.exc.InvalidDefinitionException

Question

我有一个带有以下假客户的项目

@FeignClient(name = "name", url = "${tokenService}")
public interface TokenService {
    @RequestMapping(path = "/SLJsonWebTokenWrapper/token/wrap", method = RequestMethod.POST,
        consumes = MediaType.APPLICATION_JSON_VALUE, produces = MediaType.APPLICATION_JSON_VALUE)
    Observable<Token> getToken(@RequestHeader("externalSystemCode") String systemCode,
                           @RequestBody TokenRequest tokenRequest);
}

和以下依赖关系

org.springframework.cloud:spring-cloud-starter-feign

一切正常。当我将项目更新为 Spring Boot 2（并使用 org.springframework.cloud:spring-cloud-starter-openfeign）时，对此服务的请求失败并出现异常

c.f.j.d.e.InvalidDefinitionException: Cannot construct instance of 
`rx.Observable` (no Creators, like default construct, exist): cannot 
deserialize from Object value (no delegate- or property-based Creator)
 at [Source: (ByteArrayInputStream); line: 1, column: 2]
at c.f.j.d.e.InvalidDefinitionException.from(InvalidDefinitionException.java:67)
at c.f.j.d.DeserializationContext.reportBadDefinition(DeserializationContext.java:1452)
at c.f.j.d.DeserializationContext.handleMissingInstantiator(DeserializationContext.java:1028)
at c.f.j.d.d.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:1297)
at c.f.j.d.d.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:326)
at c.f.j.d.d.BeanDeserializer.deserialize(BeanDeserializer.java:159)
at c.f.j.d.ObjectMapper._readMapAndClose(ObjectMapper.java:4013)
at c.f.j.d.ObjectMapper.readValue(ObjectMapper.java:3084)
... 1 frames excluded
... 99 common frames omitted
Wrapped by: o.s.h.c.HttpMessageConversionException: Type definition 
error: [simple type, class rx.Observable]; nested exception is 
com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot 
construct instance of `rx.Observable` (no Creators, like default 
construct, exist): cannot deserialize from Object value (no delegate- 
or property-based Creator)
at [Source: (ByteArrayInputStream); line: 1, column: 2]
at o.s.h.c.j.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:240)
at o.s.h.c.j.AbstractJackson2HttpMessageConverter.read(AbstractJackson2HttpMessageConverter.java:225)
... 3 frames excluded
at f.o.OptionalDecoder.decode(OptionalDecoder.java:36)
at f.SynchronousMethodHandler.decode(SynchronousMethodHandler.java:170)
... 93 common frames omitted
Wrapped by: f.c.DecodeException: Type definition error: [simple type, class rx.Observable]; nested exception is com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of `rx.Observable` (no Creators, like default construct, exist): cannot deserialize from Object value (no delegate- or property-based Creator)
 at [Source: (ByteArrayInputStream); line: 1, column: 2]

我该如何解决？

P.S。这个问题类似于Spring cloud netflix and HystrixObservable --> JsonMappingException，但没有答案

Answer 1

当您将 Feign 依赖更改为：

<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
<version>2.1.0.RELEASE</version>

对您的 Feign 客户端的注释也将更改为例如：

@FeignClient(name = "your-service-name", configuration = FeignConfig.class)

Answer 2

添加这个选项解决了我的问题

feign.hystrix.enabled: true

来自 openfeign 和 Observable 的 @FeignClient 导致 fasterxml.jackson.databind.exc.InvalidDefinitionException

@FeignClient from openfeign and Observable leads to fasterxml.jackson.databind.exc.InvalidDefinitionException

java

spring

spring-boot

spring-cloud-feign

feign