@EnableFeignClients
@EnableDiscoveryClient
@SpringBootApplication
public class Application {

    @RestController
    public class UploadController {

        @PostMapping(value = "/uploadFile"
 
, consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
        public String handleFileUpload(@RequestPart(value = "file") MultipartFile file) {
            return file.getName();
        }

    }

    public static void main(String[] args) {
        new SpringApplicationBuilder(Application.class).web(true
 
).run(args);
    }

}

<dependency>
   <groupId>io.github.openfeign.form</groupId>
   <artifactId>feign-form</artifactId>
   <version>3.0.3</version>
</dependency>
<dependency>
   <groupId>
 
io.github.openfeign.form</groupId>
   <artifactId>feign-form-spring</artifactId>
   <version>3.0.3</version>
</dependency>
<dependency>
   <groupId>commons-fileupload</groupId>
   <artifactId>commons-fileupload</artifactId>
   <version>1.3.3</version>
</dependency>

@EnableFeignClients
@EnableDiscoveryClient
@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        new SpringApplicationBuilder(Application.class).web(true).run(args);
    }

}

@FeignClient(value = "upload-server", configuration = UploadService.MultipartSupportConfig.class)
public interface UploadService {

    @PostMapping(value = "/uploadFile", consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
    String handleFileUpload(@RequestPart(value = "file") MultipartFile file);

    @Configuration
    class MultipartSupportConfig {
        @Bean
        public Encoder feignFormEncoder() {
            return new SpringFormEncoder();
        }
    }

}

@Slf4j
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest
public class UploadTester {

    @Autowired
    private UploadService uploadService;

    @Test
    @SneakyThrows
    public void testHandleFileUpload() {

        File file = new File("upload.txt");
        DiskFileItem fileItem = (DiskFileItem) new DiskFileItemFactory().createItem("file",
                MediaType.TEXT_PLAIN_VALUE, true, file.getName());

        try (InputStream input = new FileInputStream(file); OutputStream os = fileItem.getOutputStream()) {
            IOUtils.copy(input, os);
        } catch (Exception e) {
            throw new IllegalArgumentException("Invalid file: " + e, e);
        }

        MultipartFile multi = new CommonsMultipartFile(fileItem);

        log.info(uploadService.handleFileUpload(multi));
    }

}