asp.net core分块上传文件示例_ASP.NET教程

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 name="viewport" content="width=device-width" />

									  <title>Index</title>

									  <link href="/lib/bootstrap/dist/css/bootstrap.css" rel="external nofollow" rel="stylesheet" />

									  <script src="/lib/jquery/dist/jquery.js"></script>

									  <script src="/lib/bootstrap/dist/js/bootstrap.js"></script>

									  <script src="/js/UploadJs.js"></script>

									</head>

									<body>

									  <div class="row" style="margin-top:20%">

									    <div class="col-lg-4"></div>

									    <div class="col-lg-4">

									      <input type="text" value="请选择文件" size="20" name="upfile" id="upfile" style="border:1px dotted #ccc">

									      <input type="button" value="浏览" onclick="path.click()" style="border:1px solid #ccc;background:#fff">

									      <input type="file" id="path" style="display:none" multiple="multiple" onchange="upfile.value=this.value">

									      <br />

									      <span id="output">0%</span>

									      <button type="button" id="file" onclick="UploadStart()" style="border:1px solid #ccc;background:#fff">开始上传</button>

									    </div>

									    <div class="col-lg-4"></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 http://go.microsoft.com/fwlink/?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;

									    }

									  }

									}