How to bind javascript array with @RequestParam using FormData?

Question

The problem is binding javascript arraylist with RequestParam annotation. I have a form data like this works fine if there is no nokDataList. nokInfoDatas is an javascript array that in console it looks:

var requestData = JSON.stringify(nokInfoDatas);
    console.log("nokInfoDatas");
    console.log(nokInfoDatas);
    console.log("requestData");
    console.log(requestData);
var fd = new FormData();
        fd.append('photo', file);
        fd.append('testId', testId);
        fd.append('nokDataList', nokInfoDatas);
var ajaxData = {
            type: "POST",
            data: fd,
            processData : false,
            contentType : false,
            url: sendUrl,
            headers: headersData,
    };

Backend side:

public @ResponseBody String answer(HttpServletRequest request, 
            @RequestParam(value = "photo") MultipartFile photo,
            @RequestParam(value = "testId") String testId,
        @RequestParam(value = "nokDataList") List<NokDataDTO> nokInfoDtos
            )

Answer 1

You can try as follows :

Create a Blob with your JSON data (requestData) :

var requestData = JSON.stringify(nokInfoDatas);
var fd = new FormData();
fd.append('photo', file);
fd.append('testId', testId);
fd.append('nokDataList', new Blob([requestData], {
  type: "application/json"
}));

Change @RequestParam to @RequestPart for parsing JSON with multi-part.

public @ResponseBody String answer(HttpServletRequest request, 
       @RequestParam(value = "photo") MultipartFile photo,
       @RequestParam(value = "testId") String testId,
       @RequestPart(value = "nokDataList") List<NokDataDTO> nokInfoDtos
      )