異常 FallbackDefinitionException: Incompatible return type

問題： 

com.netflix.hystrix.contrib.javanica.exception.FallbackDefinitionException: Incompatible return types. 
Command method: public com.zjrcinfo.zjguahao.product.api.dto.PageData com.zjrcinfo.zjguahao.product.api.client.ProductRibbonClient.getProductServiceList(com.zjrcinfo.zjguahao.product.api.dto.GetProductServiceListRequest);
Fallback method: public com.zjrcinfo.zjguahao.product.api.dto.GetProductServiceListResponse com.zjrcinfo.zjguahao.product.api.client.ProductRibbonClient.getProductServiceListError(com.zjrcinfo.zjguahao.product.api.dto.GetProductServiceListRequest,java.lang.Throwable);
Hint: Different size of types variables.
Command  type literals size = 2: [com.zjrcinfo.zjguahao.product.api.dto.PageData<com.zjrcinfo.zjguahao.product.api.bo.ProductServiceInfoBo>, class com.zjrcinfo.zjguahao.product.api.bo.ProductServiceInfoBo]
Fallback type literals size = 1: [class com.zjrcinfo.zjguahao.product.api.dto.GetProductServiceListResponse]

Command type literal pos: unknown; Fallback type literal pos: unknown
	at com.netflix.hystrix.contrib.javanica.utils.FallbackMethod.validateReturnType(FallbackMethod.java:180)
	at com.netflix.hystrix.contrib.javanica.utils.FallbackMethod.validateReturnType(FallbackMethod.java:138)
	at com.netflix.hystrix.contrib.javanica.aop.aspectj.HystrixCommandAspect.setFallbackMethod(HystrixCommandAspect.java:344)
	at com.netflix.hystrix.contrib.javanica.aop.aspectj.HystrixCommandAspect.access$300(HystrixCommandAspect.java:66)
	at com.netflix.hystrix.contrib.javanica.aop.aspectj.HystrixCommandAspect$MetaHolderFactory.metaHolderBuilder(HystrixCommandAspect.java:187)
	at com.netflix.hystrix.contrib.javanica.aop.aspectj.HystrixCommandAspect$CommandMetaHolderFactory.create(HystrixCommandAspect.java:269)
	at com.netflix.hystrix.contrib.javanica.aop.aspectj.HystrixCommandAspect$MetaHolderFactory.create(HystrixCommandAspect.java:177)
	at com.netflix.hystrix.contrib.javanica.aop.aspectj.HystrixCommandAspect.methodsAnnotatedWithHystrixCommand(HystrixCommandAspect.java:95)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:483)
	at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:644)
	at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:633)
	at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:70)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:174)
	at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:688)
	at com.zjrcinfo.zjguahao.product.api.client.ProductRibbonClient$$EnhancerBySpringCGLIB$$4f5a4232.getProductServiceList(<generated>)
	at com.zjrcinfo.zjguahao.common.xmsapi.service.impl.SysProductService.getProductServiceList(SysProductService.java:89)
	at com.zjrcinfo.zjguahao.common.xmsapi.controller.SysProductController.getProductServiceList(SysProductController.java:50)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

代碼

 結論

原因是由於異常方法返回值與hystrix方法不同引起的；

1.Hystrix的原方法和異常方法一定要完全相似，參數多了一個Throwable；

2.原方法和異常方法參數和返回值一定保持一致；

 修復