File Upload Using Feign – multipart/form-data

Sure! Here's an example of how you can upload a file using Feign client in Java with the `multipart/form-data` content type:

1. First, make sure you have Feign client setup in your project. If not, you can add the necessary dependencies to your `pom.xml` file:

             xml
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-oauth2</artifactId>
</dependency>

             

2. Create a Feign client interface that defines the API for file uploading:

             java
import feign.Headers;
import feign.Param;
import feign.RequestLine;
import org.springframework.web.multipart.MultipartFile;

public interface FileUploadFeignClient {

    @RequestLine("POST /upload")
    @Headers("Content-Type: multipart/form-data")
    void uploadFile(@Param("file") MultipartFile file);
}

             

3. Create a Feign client configuration with `@FeignClient` annotation:

             java
import org.springframework.cloud.openfeign.FeignClient;

@FeignClient(name = "fileUploadFeignClient", url = "http://example.com")
public interface FileUploadFeignClientConfig extends FileUploadFeignClient {
}

             

4. Create a controller to handle the file upload request:

             java
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

@RestController
public class FileUploadController {

    @Autowired
    private FileUploadFeignClientConfig fileUploadFeignClient;

    @PostMapping("/upload")
    public void uploadFile(@RequestParam("file") MultipartFile file) {
        fileUploadFeignClient.uploadFile(file);
    }
}

             

5. Now, you can test the file upload by sending a POST request with a file to the `/upload` endpoint using tools like Postman or curl.

6. When you send a POST request with a file attached, Feign client will handle the request and upload the file to the specified endpoint.

Output:

– If the file upload is successful, you will receive a successful response (HTTP status code 200) from the server.

– If there is an issue with the file upload, you will receive an error response indicating the issue.

This example demonstrates how to upload a file using Feign client with the `multipart/form-data` content type. Remember to handle any exceptions and error scenarios according to your application requirements.