.netcore大文件上传 .netcore文件上传大致分为两种方式，流式和缓冲式，前者适用于大文件上传，后者则适用于小文件上传，具体区别如下。缓冲：通过模型绑定先把整个文件保存到内存，然后我们通过IFormFile得到stream，优点是效率高，缺点对内存要求大，适用于小文件上传。流式处理：直接读取请求体装载后的Section 对应的stream 直接操作strem即可，无需把整个请求体读入内存；适用于大文件上传。 /// <summary> /// 大文件上传，参数“softPackage”，可自定义 /// </summary> /// <returns></returns> [HttpPost("UploadSoftPackage")] [RequestSizeLimit(419430400)/*文件大小上限，400M，可自定义*/] public async Task<HttpResponseMessage> UploadSoftPackage() { try { //获取boundary var boundary = HeaderUtilities.RemoveQuotes(MediaTypeHeaderValue.Parse(Request.ContentType).Boundary).Value ?? ""; //得到reader var reader = new MultipartReader(boundary, HttpContext.Request.Body); var section = await reader.ReadNextSectionAsync(); var webRoot = _hostingEnvironment.WebRootPath/*IWebHostEnvironment，用于获取网站、API根目录*/; bool flag = false; long fileLen = 0; List<string> extList = new List<string>() { ".exe", ".apk", ".zip", ".rar" }; var savePath = string.Empty; //读取section while (section != null) { var hasContentDispositionHeader = ContentDispositionHeaderValue.TryParse(section.ContentDisposition, out var contentDisposition); if (hasContentDispositionHeader) { if (contentDisposition.Name == "softPackage") { var fileName = contentDisposition.FileName.Value; var fileExt = Path.GetExtension(fileName); if (extList.Contains(fileExt)) { flag = true; var dir = Path.Combine(webRoot, "SoftPackage"); if (!Directory.Exists(dir)) { Directory.CreateDirectory(dir); } savePath = $"/SoftPackage/{fileName}"; fileLen = await WriteFileAsync(section.Body, Path.Combine(dir, fileName)); } else { return JsonManager.SimpleCustResponse("unsupported media type"); } } } section = await reader.ReadNextSectionAsync(); } if (!flag) { return JsonManager.SimpleCustResponse("softPackage is require"); } else { if (fileLen > 0) { return JsonManager.ReturnSuccessResponse(savePath); } else { return JsonManager.SimpleCustResponse("file upload failed"); } } } catch (Exception ex) { _logger.LogError(ex.ToString()); return JsonManager.SimpleStatusResponse(ResultCode.OPERATE_FAILED); } } /// <summary> /// 写文件导到磁盘 /// </summary> /// <param name="stream">流</param> /// <param name="path">文件保存路径</param> /// <returns></returns> private async Task<int> WriteFileAsync(Stream stream, string path) { const int FILE_WRITE_SIZE = 84975;//写出缓冲区大小 int writeCount = 0; using (FileStream fileStream = new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.Write, FILE_WRITE_SIZE, true)) { byte[] byteArr = new byte[FILE_WRITE_SIZE]; int readCount = 0; while ((readCount = await stream.ReadAsync(byteArr, 0, byteArr.Length)) > 0) { await fileStream.WriteAsync(byteArr, 0, readCount); writeCount += readCount; } } return writeCount; }

.netcore接口附带参数文件上传 因为项目上需要用到文件上传且附带其他参数，需求是有一个winfrom程序要上传文件给netcore webapi 并且上传接口要能够支持多个参数的传递方式；期间也遇到了很多问题，随手记录一下，方便自己也也方便他人。经过实验，采用multipart/form-data的方式可实现带文件、参数；此方法仅适用于小文件上传，大文件上传不建议使用。示例代码首先新建参数接收类 ，类中包含文件与其他参数；参数可自定义，代码如下： public class Snapshot { public string directoy { get; set; } public int type { get; set; } public IFormFile picture { get; set; } public string id { get; set; } }http post图片上传方法，如下代码： [HttpPost("UploadSnaphot")] public async Task<HttpResponseMessage> UploadSnaphot([FromForm] Snapshot snapshot) { return await Task.Run(() => { try { if (snapshot == null) { return JsonManager.SimpleCustResponse("Invalid parameter"); } else if (string.IsNullOrEmpty(snapshot.id)) { return JsonManager.SimpleCustResponse("Invalid parameter warehouseId"); } else if (snapshot.type != 0 && snapshot.type != 1) { return JsonManager.SimpleCustResponse("Invalid parameter type"); } else if (string.IsNullOrEmpty(snapshot.directoy) || !DateTime.TryParseExact(snapshot.directoy, "yyyyMMdd", CultureInfo.InvariantCulture, DateTimeStyles.None, out DateTime _dir)) { return JsonManager.SimpleCustResponse("Invalid parameter directoy"); } else if (snapshot.picture == null) { return JsonManager.SimpleCustResponse("Invalid parameter picture"); } else if (snapshot.picture.Length > 1024 * 1024 * 3)//3M { return JsonManager.SimpleCustResponse("file size too big"); } else { //判断图片扩展名是否正确 List<string> extList = new List<string>() { ".png", ".jpg" }; var ext = Path.GetExtension(snapshot.picture.FileName).ToLower(); if (!extList.Contains(ext)) { return JsonManager.SimpleCustResponse("unsupport media type"); } else { using (MemoryStream ms = new MemoryStream()) { //拷贝文件到内存流 snapshot.picture.CopyTo(ms); var tmp = ms.GetBuffer(); var fileType = tmp[0].ToString() + tmp[1].ToString(); //通过判断文件头类型判断是否图片格式，13780 png,255216 jpg if (fileType == "13780" || fileType == "255216") { var _path = “{_hostingEnvironment.WebRootPath}\\SnapPic\\TestUpload\\{snapshot.id.Replace("-", "")}\\{snapshot.directoy}"; if (!Directory.Exists(_path)) { Directory.CreateDirectory(_path); } Bitmap.FromStream(ms).Save([ DISCUZ_CODE_1 ]quot;{_path}\\{snapshot.picture.FileName}"); return JsonManager.SimpleStatusResponse(ResultCode.OPERATE_SUCCESS); } else { return JsonManager.SimpleCustResponse("unsupport media type"); } } } } } catch (Exception ex) { //_logger.LogError(ex.ToString()); return JsonManager.SimpleCustResponse("unsupport media type"); } }); }