Empty List<MultipartFile> when trying to upload many files in Spring with ng-file-upload
The problem was that ng-file-upload by default submits array of files using names file[0]
, file[1]
etc. It is configurable with the arrayKey
value when using Upload
Service. Setting it to empty string forces the files to be sent under the same file
key, which is correctly resolved with Spring and the @RequestParam("file") List<MultipartFile>
contains all files that has been submitted.
Upload.upload({url: url, data: {file: arrayOfFiles}, arrayKey: ''})
Try to use @ModelAttribute
like this:
@RequestMapping(value = "/{user}/attachment", method = RequestMethod.POST)
@PreAuthorize(...)
public void upload(@PathVariable User user,@ModelAttribute("uploadFile") FileUpload uploadFile) throws IllegalStateException, IOException {
List<MultipartFile> files = uploadFile.getFiles();
...
And create a class like:
public class FileUpload {
private List<MultipartFile> files;
public List<MultipartFile> getFiles() {
return files;
}
public void setFiles(List<MultipartFile> files) {
this.files= files;
}
}
That works for me, sending big 'email' object with multiple file attachments from UI to back-end:
Angular
sendEmailWithAttachments(taskId: string, template: string, email: any, modelConfig: any, files: any[]) {
let formData = new FormData();
formData.append('form', new Blob([JSON.stringify(email)], {type: 'application/json'}));
files.forEach(file => {
formData.append('files', file);
});
return this.$http({
method: 'POST',
data: formData,
url: this.baseUrl + '/' + taskId + '/email-with-attachment?template=' + template,
headers: {
'Content-Type': undefined
},
responseType: 'arraybuffer'
});
}
Java Spring
@RequestMapping(value = "{taskId}/email-with-attachment", method = RequestMethod.POST, consumes = MULTIPART_FORM_DATA_VALUE)
public void sendEmailWithAttachment(
@PathVariable String taskId,
@RequestParam String template,
@RequestParam("form") MultipartFile form,
@RequestParam("files") List<MultipartFile> files) throws IOException {
Map<String, String> parameters = new ObjectMapper().readValue(form.getInputStream(), HashMap.class);
System.out.println("taskId", taskId);
System.out.println("template", template);
System.out.println("files", files);
System.out.println("parameters", parameters);
}