Feign 如何支持进行文件上传

最近，别的项目组提出需要SDK，就利用Feign做了一个，在此期间发现上传文件是一个坑，正常的实现是无法支持文件上传，需要进行对资源有一个Convert。为了避免大家像我一样，继续掉坑里，就出现了这篇文章的初衷。

入门

• 在SDK工程处，添加包依赖

<dependency>
    <groupId>io.github.openfeign.form</groupId>
    <artifactId>feign-form</artifactId>
    <version>3.0.1</version>
</dependency>
<dependency>
    <groupId>io.github.openfeign.form</groupId>
    <artifactId>feign-form-spring</artifactId>
    <version>3.0.1</version>
</dependency>

• 在SDK工程处，创建一个Configuration

import feign.codec.Encoder;
import feign.form.spring.SpringFormEncoder;
import org.springframework.beans.factory.ObjectFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.web.HttpMessageConverters;
import org.springframework.cloud.netflix.feign.support.SpringEncoder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MultipartSupportConfig {

    @Autowired
    private ObjectFactory<HttpMessageConverters> messageConverters;

    @Bean
    public Encoder feignFormEncoder() {
        return new SpringFormEncoder(new SpringEncoder(messageConverters));
    }

}

期初在网上看到是使用下方的注入方式，一直不成功，在走头部路下，尝试了👆者方案成功了。

@FeignClient(name = "demo",configuration=MultipartSupportConfig.class)
public interface SignBaseCommonClient {
  
}

• 修改接口

@FeignClient(name = "demo")
public interface FeginExample {    
@PostMapping(value = "images", consumes = MULTIPART_FORM_DATA_VALUE)
 Resp<String> uploadImage(
            @RequestParam MultipartFile image,
            @RequestParam("id") String id);
}

@RequestPart与@RequestParam效果是一样的，大家就不用花时间在这上面了。

• 修改服务器接口

@RestController
public class FeginServiceExample {
  @PostMapping(value = "images", consumes = MULTIPART_FORM_DATA_VALUE)
    public Resp<String> uploadImage(
            @RequestParam("image") MultipartFile image,
            @RequestParam("id") String id,
            HttpServletRequest request) {
              return Resp.success(null);
            }
}

• 在启动类添加@EnableFeignClients

这个就不用多说了吧，😆

常见问题：

• HTTP Status 400 - Required request part ‘file’ is not present

请求文件参数的名称与实际接口接受名称不一致

• feign.codec.EncodeException: Could not write request: no suitable HttpMessageConverter found for request type [org.springframework.mock.web.MockMultipartFile] and content type [multipart/form-data]

转换器没有生效，检查一下MultipartSupportConfig