试试这个，

const formData = new FormData();
 formData.append("file", file);
 formData.append("reportProgress", true);

使用HTTP客户端，

return this.httpclient.post(this.urlUpload, formData);

是否设置了内容类型？如果设置了，请将其删除。

headers:{
        "Content-Type":"multipart/form-data", // remove it
},

前端：

const formData = new FormData();
    formData.append("file", file);
    formData.append("reportProgress", "true");

return this.http.post<void>(this.API_URL + '/upload', formData);

后端：

@Operation(description = "Upload File")
    @ApiResponses(value = {
            @ApiResponse(responseCode = "201", description = "File Uploaded successfully"),
            @ApiResponse(responseCode = "400", description = "Problem during file upload ")
    })
    @PostMapping(consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
    @ResponseStatus(value = HttpStatus.CREATED)
    public void upload(@RequestPart("file") final MultipartFile file) {
        //action;
    }

你真的要发送FormData到你的服务器吗？
请尝试将文件包含在FormData对象中，以便HttpClient自动添加多部分边界。

upload(file) {
    const formData = new FormData();
    formData.append('file', file);
    const req = new HttpRequest('POST', this.urlUpload, formData, {
      headers: new HttpHeaders({'Content-Type':'multipart/form-data'}),
      reportProgress: true
    });
    return this.http.request(req);
  }