报错：Caused by: java.lang.UnsupportedOperationException: null
最终请教大神debug才找到的。。。。。。。。尴尬尬尬尬
... 19 common frames omitted
Caused by: java.lang.UnsupportedOperationException: nullat java.util.Collections$UnmodifiableCollection.add(Collections.java:1055)at org.springframework.cloud.openfeign.support.FeignUtils.addTemplateParameter(FeignUtils.java:56)at org.springframework.cloud.openfeign.support.SpringMvcContract$SimpleAnnotatedParameterContext.setTemplateParameter(SpringMvcContract.java:401)at org.springframework.cloud.openfeign.annotation.RequestParamParameterProcessor.processArgument(RequestParamParameterProcessor.java:68)at org.springframework.cloud.openfeign.support.SpringMvcContract.processAnnotationsOnParameter(SpringMvcContract.java:252)at feign.Contract$BaseContract.parseAndValidateMetadata(Contract.java:110)at org.springframework.cloud.openfeign.support.SpringMvcContract.parseAndValidateMetadata(SpringMvcContract.java:147)at feign.Contract$BaseContract.parseAndValidatateMetadata(Contract.java:66)at feign.ReflectiveFeign$ParseHandlersByName.apply(ReflectiveFeign.java:154)at feign.ReflectiveFeign.newInstance(ReflectiveFeign.java:52)at feign.Feign$Builder.target(Feign.java:251)at org.springframework.cloud.openfeign.HystrixTargeter.target(HystrixTargeter.java:37)at org.springframework.cloud.openfeign.FeignClientFactoryBean.loadBalance(FeignClientFactoryBean.java:226)at org.springframework.cloud.openfeign.FeignClientFactoryBean.getTarget(FeignClientFactoryBean.java:254)at org.springframework.cloud.openfeign.FeignClientFactoryBean.getObject(FeignClientFactoryBean.java:235)at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:171)... 30 common frames omitted
原因：①
原因2:
