如何将csv文件传递到从ajax post到spring mvc controller的服务器路径？

Question

我正在尝试下载csv文件，并希望在执行我的应用程序时使用Spring MVC和Ajax Post请求将相同的csv文件上传到我的服务器位置路径。

从下面的代码中，我可以在运行我的应用程序时下载我的csv文件，但它没有同时上传到我的服务器位置路径或同时执行应用程序，我不知道为什么它是不上传。请帮我按照给定的路径上传文件。谢谢！

JS：

function download_csv(csv, filename) {
//filename = test.csv
//csv = "testname,testid
         hello,10"

    var csvFile;
    var downloadLink;
// CSV FILE
csvFile = new Blob([csv], {type: "text/csv"}); //[object Blob] 

// Download link
downloadLink = document.createElement("a");

// File name
downloadLink.download = filename;

var formData = new FormData(csvFile);
console.log(formData);//FormData {} 

    $.ajax({
            url: "/uploadFile",
            type: "POST",
            //data: filename,
            // data: new FormData(csvFile),
            data: formData,
            //  enctype: 'multipart/form-data',
            processData: false,
            contentType: false,
            cache: false,
            success: function (data) {
            // Handle upload success
                $("#upload-file-message").text("File succesfully uploaded");
                                    },
                                    error: function (errordata) {
                                        console.log("error: "+errordata);//[object Object]
                                        console.log("error data: "+JSON.stringify(errordata));

                                      }
            });//$.ajax() 

    // We have to create a link to the file
    downloadLink.href = window.URL.createObjectURL(csvFile);

    // Make sure that the link is not displayed
    downloadLink.style.display = "none";

    // Add the link to your DOM
    document.body.appendChild(downloadLink);

    // Lanzamos
    downloadLink.click();

}

控制器：

@Controller
public class MainController {

@RequestMapping(value = "/uploadFile", method = RequestMethod.POST)
  @ResponseBody

  public ResponseEntity<?> uploadFile(
          @RequestParam("filename") MultipartFile uploadfile) {

    try {
      // Get the filename and build the local file path
      String filename = uploadfile.getOriginalFilename();
      String directory = env.getProperty("paths.uploadedFiles");
      String filepath = Paths.get(directory, filename).toString(); 
      // Save the file locally
      BufferedOutputStream stream =
          new BufferedOutputStream(new FileOutputStream(new File(filepath)));
      stream.write(uploadfile.getBytes());
      stream.close();
    }
    catch (Exception e) {
      System.out.println(e.getMessage());
      return new ResponseEntity<>(HttpStatus.BAD_REQUEST);
    }

    return new ResponseEntity<>(HttpStatus.OK);
  } 

} 

application.resources：

paths.uploadedFiles = /resources/test/

POST http://localhost:8000/uploadFile 400（错误请求）

错误数据：{"readyState":4,"responseText":"{\"timestamp\":1511523835282,\"status\":400,\"error\":\"Bad Request\",\"exception\":\"org.springframework.web.bind.MissingServletRequestParameterException\",\"message\":\"Required MultipartFile parameter 'filename' is not present\",\"path\":\"/uploadFile\"}","responseJSON":{"timestamp":1511523835282,"status":400,"error":"Bad Request","exception":"org.springframework.web.bind.MissingServletRequestParameterException","message":"Required MultipartFile parameter 'filename' is not present","path":"/uploadFile"},"status":400,"statusText":"Bad Request"}