I want to upload a file inside a form to a Spring Boot API endpoint.
The UI is written in React:
export function createExpense(formData) {
return dispatch => {
axios.post(ENDPOINT,
formData,
headers: {
'Authorization': //...,
'Content-Type': 'application/json'
}
).then(({data}) => {
//...
})
.catch(({response}) => {
//...
});
};
}
_onSubmit = values => {
let formData = new FormData();
formData.append('title', values.title);
formData.append('description', values.description);
formData.append('amount', values.amount);
formData.append('image', values.image[0]);
this.props.createExpense(formData);
}
This is the java side code:
@RequestMapping(path = "/{groupId}", method = RequestMethod.POST)
public ExpenseSnippetGetDto create(@RequestBody ExpensePostDto expenseDto, @PathVariable long groupId, Principal principal, BindingResult result) throws IOException {
//..
}
But I get this exception on the Java side:
org.springframework.web.HttpMediaTypeNotSupportedException: Content type 'multipart/form-data;boundary=----WebKitFormBoundaryapHVvBsdZYc6j4Af;charset=UTF-8' not supported
How should I resolve this issue? The similar API endpoints and JavaScript side code is already working.
Note
I've seen a solution where it suggests that the request body should have 2 attributes: one which the JSON section goes under, another for the image. I'd like to see if it is possible to have it automatically converted to DTO.
Update 1
The upload payload sent by the client should be converted to the following DTO:
public class ExpensePostDto extends ExpenseBaseDto {
private MultipartFile image;
private String description;
private List<Long> sharers;
}
So you can say it's a mix of JSON and multipart.
Solution
The solution to the problem is to use FormData
on the front-end and ModelAttribute
on the backend:
@RequestMapping(path = "/{groupId}", method = RequestMethod.POST,
consumes = {"multipart/form-data"})
public ExpenseSnippetGetDto create(@ModelAttribute ExpensePostDto expenseDto, @PathVariable long groupId, Principal principal) throws IOException {
//...
}
and on the front-end, get rid of Content-Type
as it should be determined by the browser itself, and use FormData
(standard JavaScript). That should solve the problem.
Yes, you can simply do it via wrapper class.
1) Create a Class
to hold form data:
public class FormWrapper {
private MultipartFile image;
private String title;
private String description;
}
2) Create an HTML form
for submitting data:
<form method="POST" enctype="multipart/form-data" id="fileUploadForm" action="link">
<input type="text" name="title"/><br/>
<input type="text" name="description"/><br/><br/>
<input type="file" name="image"/><br/><br/>
<input type="submit" value="Submit" id="btnSubmit"/>
</form>
3) Create a method to receive form's text
data and multipart
file:
@PostMapping("/api/upload/multi/model")
public ResponseEntity<?> multiUploadFileModel(@ModelAttribute FormWrapper model) {
try {
// Save as you want as per requiremens
saveUploadedFile(model.getImage());
formRepo.save(mode.getTitle(), model.getDescription());
} catch (IOException e) {
return new ResponseEntity<>(HttpStatus.BAD_REQUEST);
}
return new ResponseEntity("Successfully uploaded!", HttpStatus.OK);
}
4) Method to save file
:
private void saveUploadedFile(MultipartFile file) throws IOException {
if (!file.isEmpty()) {
byte[] bytes = file.getBytes();
Path path = Paths.get(UPLOADED_FOLDER + file.getOriginalFilename());
Files.write(path, bytes);
}
}