springcloud 使用feign创建client接口 ，controller引入后报依赖错误 Unsatisfied dependency

如题所示，代码如下

-- 1. client
@FeignClient(name="microservice-provider-user")
public interface UserFeignClient {
  @GetMapping("/users/{id}")
  User findById(@PathVariable Long id);
}

-- 2. 控制层
@RequestMapping("/movies")
@RestController
public class MovieController {
    @Autowired
    private RestTemplate restTemplate;

    @Autowired
    private UserFeignClient userFeignClient;

    @GetMapping("/users/{id}")
    public User findById(@PathVariable Long id) {
        // 这里用到了RestTemplate的占位符能力
        User user = userFeignClient.findById(id);
        // ...电影微服务的业务...
        return user;
    }
}

-- 3. 启动类
@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients("com.caiya.movie.utils")
public class FeignMovieApplication {
    @Bean
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }

    public static void main(String[] args) {
        SpringApplication.run(FeignMovieApplication.class, args);
    }
}

 

百度了下，得到的结果是

　　1. springboot 启动类注解 @EnableFeignClients 没有写扫描包 （对比笔者自己的工程，client是在 启动类所在包的子包下，理论上不是这个问题
不过还是按提示修改后，一样报错...

　　2. 笔者自己设置了多个模块，包名存在一致的情况，为了排除这个情况导致，修改包名后还是一样的问题

最终解决方案：
　　还是 stackoverflow 牛皮，google一下就出来答案了

原因是我在复制网上教程时候，直接把 @PathVariable("id") 里面的id省略了， 自以为id可写可不写

@FeignClient(name = "microservice-provider-user")
public interface UserFeignClient {
@GetMapping("/users/{id}")
　　User findById(@PathVariable("id") Long id); // 此处（“id”）必写
}

不过这是feign的bug，后续的版本好像是解决了

解答原文及地址： https://stackoverflow.com/questions/49415197/spring-boot-2-unsatisfied-dependency-on-feign-client-when-autowired-for-servic

There was an issue in feign client before. I guess you are experiencing the same maybe because you are using an old version but what you should do is including the pathVariable name in your @PathVariable annotation like this 
    @RequestMapping(value = "/hello/{name}", method = RequestMethod.GET)
    String hello(@PathVariable(value = "name") String name);

You can find the details from 
https://github.com/spring-cloud/spring-cloud-netflix/issues/861