Multipart Request with MultipartFile as Optional Field - Spring MVC

I had the same issue and just adding the required=false worked for me; because, I don't send a file all the time. Please find the sample code below,

@RequestMapping(value = "/", method = RequestMethod.POST, produces = "application/json") public AModel createEntity(@Valid @ModelAttribute MyInsertForm myInsertForm, @RequestParam(value ="file", required=false) MultipartFile file) { // coding.. } 

Give a try by adding

(required=false) 

to multipart property in method signature.

When you wish to send one or more files using HTTP, you have to use multipart request. This means that the body of the request will be like the above,

-----------------------------9051914041544843365972754266 Content-Disposition: form-data; name="text"

text default -----------------------------9051914041544843365972754266 Content-Disposition: form-data; name="file1"; filename="a.txt" Content-Type: text/plain

Content of a.txt.

-----------------------------9051914041544843365972754266 Content-Disposition: form-data; name="file2"; filename="a.html" Content-Type: text/html

When you wish to send only data (and not files) you can send them as json, key-value pairs etc.

Spring framework uses the @ModelAttribute annotation when you wish to map a multipart request to an object. When you have a normal key-value request, you use the @RequestBody annotation. Thus, you can't have the MultipartFile optional, because you have to use different annotations. Using two different methods, one per request type, solves the issue. Example,

@RequestMapping(value = "/withFile", method = RequestMethod.POST, produces = "application/json") public ReturnModel updateFile(@ModelAttribute RequestModel rm) { // do something. } @RequestMapping(value = "/noFile", method = RequestMethod.PUT, produces = "application/json") public ReturnModel updateJson(@RequestBody RequestModel rm) { // do something else. }