webFlux 中使用 openFeign 实现远程调用遇到的问题

先沾上一段报错的控制台信息：

feign.FeignException$MethodNotAllowed: status 405 reading UserFeignService#getByUserName(String)
	at feign.FeignException.clientErrorStatus(FeignException.java:167) ~[feign-core-10.4.0.jar:na]
	Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
Error has been observed at the following site(s):
	|_ checkpoint ⇢ org.springframework.cloud.gateway.filter.WeightCalculatorWebFilter [DefaultWebFilterChain]
	|_ checkpoint ⇢ HTTP GET "/getByUserName?username=liqiye" [ExceptionHandlingWebHandler]
Stack trace:
		at feign.FeignException.clientErrorStatus(FeignException.java:167) ~[feign-core-10.4.0.jar:na]
		at feign.FeignException.errorStatus(FeignException.java:141) ~[feign-core-10.4.0.jar:na]
		at feign.FeignException.errorStatus(FeignException.java:133) ~[feign-core-10.4.0.jar:na]
		at feign.codec.ErrorDecoder$Default.decode(ErrorDecoder.java:92) ~[feign-core-10.4.0.jar:na]
		at feign.SynchronousMethodHandler.executeAndDecode(SynchronousMethodHandler.java:151) ~[feign-core-10.4.0.jar:na]
		at feign.SynchronousMethodHandler.invoke(SynchronousMethodHandler.java:80) ~[feign-core-10.4.0.jar:na]
		at feign.ReflectiveFeign$FeignInvocationHandler.invoke(ReflectiveFeign.java:103) ~[feign-core-10.4.0.jar:na]
		at com.sun.proxy.$Proxy146.getByUserName(Unknown Source) ~[na:na]
		at com.liqiye.springcloud.controller.Controller.hello(Controller.java:29) ~[classes/:na]