How can i upload multi file.

[JokerSun]

In my case , i want to upload multi file ,but i get exception java.lang.IllegalStateException: Method has too many Body parameters,my code like that

@FeignClient(configuration = MultipartFormDataConfig.class)
public class Demo{
	@PostMapping(
		path = "/upload",
		consumes = org.springframework.http.MediaType.MULTIPART_FORM_DATA_VALUE
	)
	Response uploadFile(
		@RequestPart MultipartFile file1,
		@RequestPart MultipartFile file2
	);
}

[xxlabaza]

@JokerSun the feature was broken, but I've already fixed it in the new version 3.8.0

Take a look at those client examples 1 and 2. There is an example of the server side

Your sample with several MultipartFile argument doesn't work, because of Spring's contract implementation and it throws an exception like IllegalStateException: Method has too many Body parameters in such cases.

[JokerSun]

@xxlabaza Thanks for your supporting, i got the example and my question isn't just that , according to the protocol of multipart-form/data carrying either named parameters in request body is allowed, so how can i construct a interface like that

@PostMapping(
		path = "/upload",
		consumes = org.springframework.http.MediaType.MULTIPART_FORM_DATA_VALUE
)
Response uploadFile(
		@RequestParam String parameter1,
		@RequestPart String parameter2,
		@ReuqestPart String json,
		@RequestPart MultipartFile file1,
		@RequestPart MultipartFile file2
);

then i hope it will be send like that

POST /upload?parameter1=**** HTTP/1.1
*** headers ***
------FormBoundary
Content-Disposition: form-data; name="parameter2"

value
------FormBoundary
Content-Disposition: form-data; name="json"
Content-Type: application/json

value
------FormBoundary
Content-Disposition: form-data; name="image"; filename="file1"
Content-Type: application/octet-stream

value
------FormBoundary
Content-Disposition: form-data; name="image"; filename="file2"
Content-Type: application/octet-stream

value
------FormBoundary--

Is there a solution?

[jianguyuxing]

不需要重写Contract啊。但是feign默认使用的是SpringMVC 的Contract。
一、需要声明使用feign的自带Contract，不让它使用SpringMvcContract。
第二点，需要使用我提到的那个encoder。
三、接口的请求形式不是你写的这样，我写成这样是在生产者端接收用的。在FeignClient端用的注解不是这样的，FeignClient客户端的请求路径用的是@RequestLine注解和@ Param注解，只有生产者端才使用@PostMapping和@RequestPart注解。你可以认真看下我给的例子。这里给你个博客地址吧。https://blog.csdn.net/qq_34523427/article/details/88863800

[JokerSun]

@jianguyuxing 谢谢您在百忙之中抽空回复，我知道我的写法现有的contract不支持，但是我是希望实现这种需求，因为这样的写法能够更好的表达这个接口的行为，并且能够跟spring mvc的写法保持一致。您的例子我看了，确实可以实现功能，但是使用的是feign的原生注解，这样就和我们公司现有的代码风格产生冲突。我会抽时间把我的想法实现出来，然后再与您交流。

[xxlabaza]

Так, на сколько я вижу вы тут сами уже во всём разобрались...

[rojekabc]

Ok. I see, that this issue is closed, but I'll describe here a little workaround. I hope this will help someone. I resolve this in the issue, when I's trying to send something like this via feign client:

void upload(
   @RequestPart(name="main") MultipartFile mainFile,
   @RequestPart(name="attachments") MultipartFile[] attachments);

In case of two request parts, when tries create feign client instance Method has too many Body parameters occurs.
If I change them to RequestParam, than I get nothing (null).

So I do this in such way, that I create two interface API.
The first version, with two RequestPart, is used on side of Controller implementation - in such way it recognizes correctly incoming parts and puts as argues.
The second version, used to create feign client, looks like this

void upload(@RequestPart MultipartFile[] documents);

I'm using this with feign client configuration

    @Configuration
    class MultipartSupportConfig {

        @Bean
        public Encoder feignFormEncoder(ObjectFactory<HttpMessageConverters> messageConverters) {
            return new SpringFormEncoder(new SpringEncoder(messageConverters));
        }
    }

and with fix from PR: #97 - it's needed, if for one field name (here attachments) we'd like send more than one multipart-file.

Then, if we'd like to use upload via feign client, we should call upload and create named multiparts.
In this example example:

MultipartFile[] documents = new MultipartFile[3];
documents[0] = new MockMultipartFile("main", "sample-file.bin", MediaType.APPLICATION_OCTET_STREAM_VALUE, "MAIN-FILE-CONTENT".getBytes());
documents[1] = new MockMultipartFile("attachments", "attach-1.bin", MediaType.APPLICATION_OCTET_STREAM_VALUE, "ONE-CONTENT".getBytes());
documents[2] = new MockMultipartFile("attachments", "attach-2.bin", MediaType.APPLICATION_OCTET_STREAM_VALUE, "TWO-CONTENT".getBytes());
FeignClientInstance.upload(documents);

In this way multi part files names are used as field names. This will be recognized by controller and assigned to dedicated argues.