CODEWITHSUNDEEP
javaspringspring-bootfile-upload
Jamie
Jamie

Reputation: 33

Spring Boot MultipartFile always has value of null

So I'm making a RESTful API backend for a JavaScript frontend and want to upload a file to Google Cloud Storage. I have this function to handle the file upload:

@RequestMapping(value = "/uploadFile", method = RequestMethod.POST, consumes = { "multipart/form-data" })
    public ResponseEntity<?> uploadFile(@ModelAttribute("file") FileDTO fileDTO) {
        FunctionResponse uploadResponse = cloudStorage.uploadObject(fileDTO.getFile());
        if (uploadResponse.successful()) {
            return new ResponseEntity<>(uploadResponse.getMessage(), HttpStatus.OK);
        } else {
            return new ResponseEntity<>(uploadResponse.getMessage(), HttpStatus.BAD_REQUEST);
        }
    }

My fileDTO class looks like this:

public class FileDTO implements Serializable {

    private MultipartFile file;

    public MultipartFile getFile() {
        return file;
    }
}

However whenever I try and access the MultipartFile it always throws a java.lang.NullPointerException. I have tried various SO answers from threads with similar problems but none have worked so far.

I have multipart.enabled=true in my application.properties.

Any help would be appreciated and let me know if you need any more information.

Upvotes: 0

Views: 2495

Answers (1)

Matheus
Matheus

Reputation: 3390

When a multipart/form-data request arrives, the data must be obtained by using @RequestParam, not @ModelAttribute + if the value you need of the request is a file, then, it should be deserialized into a MultipartFile object.

@RequestMapping(value = "/uploadFile", method = RequestMethod.POST, consumes = {"multipart/form-data"})
public ResponseEntity<?> uploadFile(@RequestParam(name = "file") MultipartFile file) {
    // your handle ...
}

Upvotes: 1

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