Spring Cloud 微服務開發使用FeignClient 配置回退函式報錯Incompatible fallback instance. Fallback/fallbackFactory
阿新 • • 發佈：2021-01-15
技術標籤：【JAVA開發】【異常處理】spring cloudspring boot
在spring的微服務應用開發過程中，如果配置了異常回退機制做熔斷處理，FeignClient 的註解指定回退函式時使用了fallback做為引數，但定義回退的類實現了FallBackFactory介面。
啟消費者伺服器控制檯通常會報錯，如下：
Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled. 2021-01-14 22:29:31.632 ERROR 11600 --- [ main] o.s.boot.SpringApplication : Application startup failed org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'movieController': Unsatisfied dependency expressed through field 'userFeignClient'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'cn.rdfeng.controller.UserFeignClient': FactoryBean threw exception on object creation; nested exception is java.lang.IllegalStateException: Incompatible fallback instance. Fallback/fallbackFactory of type class cn.rdfeng.controller.FeignClientFallbackFactory is not assignable to interface cn.rdfeng.controller.UserFeignClient for feign client microservice-provider-user at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:588) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1225) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:552) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:759) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:866) ~[spring-context-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542) ~[spring-context-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:761) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE] at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:371) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1186) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1175) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE] at cn.rdfeng.ConsumerMovieApplication.main(ConsumerMovieApplication.java:27) [classes/:na] Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'cn.rdfeng.controller.UserFeignClient': FactoryBean threw exception on object creation; nested exception is java.lang.IllegalStateException: Incompatible fallback instance. Fallback/fallbackFactory of type class cn.rdfeng.controller.FeignClientFallbackFactory is not assignable to interface cn.rdfeng.controller.UserFeignClient for feign client microservice-provider-user at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:175) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.getObjectFromFactoryBean(FactoryBeanRegistrySupport.java:103) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.getObjectForBeanInstance(AbstractBeanFactory.java:1626) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:254) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:207) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.support.DefaultListableBeanFactory.addCandidateEntry(DefaultListableBeanFactory.java:1297) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1263) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1099) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1064) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] ... 19 common frames omitted Caused by: java.lang.IllegalStateException: Incompatible fallback instance. Fallback/fallbackFactory of type class cn.rdfeng.controller.FeignClientFallbackFactory is not assignable to interface cn.rdfeng.controller.UserFeignClient for feign client microservice-provider-user at org.springframework.cloud.netflix.feign.HystrixTargeter.getFromContext(HystrixTargeter.java:92) ~[spring-cloud-netflix-core-1.2.4.RELEASE.jar:1.2.4.RELEASE] at org.springframework.cloud.netflix.feign.HystrixTargeter.targetWithFallback(HystrixTargeter.java:77) ~[spring-cloud-netflix-core-1.2.4.RELEASE.jar:1.2.4.RELEASE] at org.springframework.cloud.netflix.feign.HystrixTargeter.target(HystrixTargeter.java:41) ~[spring-cloud-netflix-core-1.2.4.RELEASE.jar:1.2.4.RELEASE] at org.springframework.cloud.netflix.feign.FeignClientFactoryBean.loadBalance(FeignClientFactoryBean.java:146) ~[spring-cloud-netflix-core-1.2.4.RELEASE.jar:1.2.4.RELEASE] at org.springframework.cloud.netflix.feign.FeignClientFactoryBean.getObject(FeignClientFactoryBean.java:167) ~[spring-cloud-netflix-core-1.2.4.RELEASE.jar:1.2.4.RELEASE] at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:168) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE] ... 29 common frames omitted
分析控制檯列印的日誌資訊，不難發現實現介面的託底函式與註釋配置不一致
Caused by: java.lang.IllegalStateException: Incompatible fallback instance. Fallback/fallbackFactory of type class cn.rdfeng.controller.FeignClientFallbackFactory is not assignable to interface cn.rdfeng.controller.UserFeignClient for feign client microservice-provider-user
此時將註解引數名修改一下即可
改以下這個：
再執行消費端的啟動類，就不會報錯了。