写完asp.net多文件上传后，感觉这种上传还是有很多缺陷，于是。。。（省略一万字，不废话）。这里我没用传统的asp.net，而选择了开源的asp.net core，原因很简单，.net core是.net新的开始，更是.net和.net开发者的未来，希望.net发展越来越好（大家的工资越来越高(●ˇ∀ˇ●)）。
1.前端的实现：
1).html：
<html> <head> <meta content="width=device-width" /> <title>Index</title> <link href="https://www.jb51.net/lib/bootstrap/dist/css/bootstrap.css" /> <script src="https://www.jb51.net/lib/jquery/dist/jquery.js"></script> <script src="https://www.jb51.net/lib/bootstrap/dist/js/bootstrap.js"></script> <script src="https://www.jb51.net/js/UploadJs.js"></script> </head> <body> <div> <div></div> <div> <input type="text" value="请选择文件" size="20"> <input type="button" value="浏览"> <input type="file" multiple="multiple" onchange="upfile.value=this.value"> <br /> <span>0%</span> <button type="button">开始上传</button> </div> <div></div> </div> </body> </html>
2).javascript：
var UploadPath = ""; //开始上传 function UploadStart() { var file = $("#path")[0].files[0]; AjaxFile(file, 0); } function AjaxFile(file, i) { var name = file.name, //文件名 size = file.size, //总大小shardSize = 2 * 1024 * 1024, shardSize = 2 * 1024 * 1024,//以2MB为一个分片 shardCount = Math.ceil(size / shardSize); //总片数 if (i >= shardCount) { return; } //计算每一片的起始与结束位置 var start = i * shardSize, end = Math.min(size, start + shardSize); //构造一个表单，FormData是HTML5新增的 var form = new FormData(); form.append("data", file.slice(start, end)); //slice方法用于切出文件的一部分 form.append("lastModified", file.lastModified); form.append("fileName", name); form.append("total", shardCount); //总片数 form.append("index", i + 1); //当前是第几片 UploadPath = file.lastModified //Ajax提交文件 $.ajax({ url: "/Upload/UploadFile", type: "POST", data: form, async: true, //异步 processData: false, //很重要，告诉jquery不要对form进行处理 contentType: false, //很重要，指定为false才能形成正确的Content-Type success: function (result) { if (result != null) { i = result.number++; var num = Math.ceil(i * 100 / shardCount); $("#output").text(num + '%'); AjaxFile(file, i); if (result.mergeOk) { var filepath = $("#path"); filepath.after(filepath.clone().val("")); filepath.remove();//清空input file $('#upfile').val('请选择文件'); alert("success!!!"); } } } }); }
这里的主要思路是利用html5 File api的slice方法把文件分块，然后new一个FormData()对象用于储存文件数据，之后就是递归调用AjaxFile方法直至上传完毕。
2.后台C#：
using System; using System.Collections.Generic; using System.Linq; using System.Threading.Tasks; using Microsoft.AspNetCore.Mvc; using System.IO; // For more information on enabling MVC for empty projects, visit ?LinkID=397860 namespace DotNet.Upload.Controllers { public class UploadController : Controller { // GET: /<controller>/ public IActionResult Index() { return View(); } [HttpPost] public async Task<ActionResult> UploadFile() { var data = Request.Form.Files["data"]; string lastModified = Request.Form["lastModified"].ToString(); var total = Request.Form["total"]; var fileName = Request.Form["fileName"]; var index = Request.Form["index"]; string temporary = Path.Combine(@"E:\浏览器", lastModified);//临时保存分块的目录 try { if (!Directory.Exists(temporary)) Directory.CreateDirectory(temporary); string filePath = Path.Combine(temporary, index.ToString()); if (!Convert.IsDBNull(data)) { await Task.Run(() => { FileStream fs = new FileStream(filePath, FileMode.Create); data.CopyTo(fs); }); } bool mergeOk = false; if (total == index) { mergeOk = await FileMerge(lastModified, fileName); } Dictionary<string, object> result = new Dictionary<string, object>(); result.Add("number", index); result.Add("mergeOk", mergeOk); return Json(result); } catch (Exception ex) { Directory.Delete(temporary);//删除文件夹 throw ex; } } public async Task<bool> FileMerge(string lastModified,string fileName) { bool ok = false; try { var temporary = Path.Combine(@"E:\浏览器", lastModified);//临时文件夹 fileName = Request.Form["fileName"];//文件名 string fileExt = Path.GetExtension(fileName);//获取文件后缀 var files = Directory.GetFiles(temporary);//获得下面的所有文件 var finalPath = Path.Combine(@"E:\浏览器", DateTime.Now.ToString("yyMMddHHmmss") + fileExt);//最终的文件名（demo中保存的是它上传时候的文件名，实际操作肯定不能这样） var fs = new FileStream(finalPath, FileMode.Create); foreach (var part in files.OrderBy(x => x.Length).ThenBy(x => x))//排一下序，保证从0-N Write { var bytes = System.IO.File.ReadAllBytes(part); await fs.WriteAsync(bytes, 0, bytes.Length); bytes = null; System.IO.File.Delete(part);//删除分块 } fs.Close(); Directory.Delete(temporary);//删除文件夹 ok = true; } catch (Exception ex) { throw ex; } return ok; } } }