一、微服務搭建
1.參考之前的文章，創建用戶中心開放接口模塊user-open-api。
新增模塊依賴時，選擇
2.修改POM文件。
(1)cloud-provider和cloud-consumer模塊加上user-open-api的依賴
(2)cloud-dependencies模塊加上spring-cloud-dependencies依賴
(3)michael-cloud項目增加user-open-api子模塊
3.user-open-api模塊創建client和dto包
4.去掉自動生成的代碼
（1）新增UserRemoteClient接口
（2）新增UseDto
（3）修改CloudConsumerApplication類，類名上方加上@EnableFeignClients(basePackages = "com.plkd.usercenter.client")
（4）cloud-provider模塊新增
（5）cloud-consumer模塊新增
5.啟動服務后，瀏覽器輸入http://localhost:8080/order/getUserByOrderId/2
服務調用成功
6.如果消費者需要消費多個不同的服務提供者，可以按照如下修改
@EnableFeignClients(basePackages = {"com.plkd.usercenter.client","com.plkd.usercenter.api"})
二、問題處理
1.系統提示以下異常：
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'orderController': Unsatisfied dependency expressed through method 'setUserRemoteClient' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.plkd.usercenter.client.UserRemoteClient': FactoryBean threw exception on object creation; nested exception is java.lang.IllegalStateException: Method UserRemoteClient#findUserByUserName(String) not annotated with HTTP method type (ex. GET, POST)
解決方案：
方法上添加@RequestMapping(value = "/findUserByUserName/{userName}",method = RequestMethod.GET)
並增加@PathVariable
2.系統提示以下異常：
feign.FeignException$NotFound: [404] during [GET] to [http://cloud-provider/user/findUserByUserName?userName=michael] [UserRemoteClient#findUserByUserName(String)]: [{"timestamp":"2020-03-23T09:47:04.917+0000","status":404,"error":"Not Found","message":"No message available","path":"/user/findUserByUserName"}]
原因：路徑不對
修改成@RequestMapping(value = "/user/findUserByUserName/{userName}",method = RequestMethod.GET)即可
3.系統提示以下異常：
NotAllowed: [405] during [GET] to [http://cloud-user-center/user/name] [IUserOpenService#findUserByUserName(String)]: [{"timestamp":"2020-03-23T08:24:18.400+0000","status":405,"error":"Method Not Allowed","message":"Request method 'POST' not supported","path":"/user/name"}]
原因：如果feign代理的是get請求，則每個參數必須帶上@RequestParam，否則會報post not support！
解決方案：參數帶上@RequestParam("userName")
4.系統提示以下異常：
The bean 'cloud-provider.FeignClientSpecification' could not be registered. A bean with that name has already been defined and overriding is disabled.
原因：多個接口上的@FeignClient(“相同服務名”)會報錯，overriding is disabled，即出現了相同的Bean名。
解決方案：將@FeignClient("cloud-provider")修改成@FeignClient(name="cloud-provider", contextId = "cloud-provider-1")
參考文章：https://blog.csdn.net/u012211603/article/details/84312709