一、.Net Core 分块上传文件

一、.Net Core 分块上传文件

一、前端实现

@*
    For more information on enabling MVC for empty projects, visit http://go.microsoft.com/fwlink/?LinkID=397860
*@
@{
    ViewData["Title"] = "Index";
    Layout = null;
}
<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
    <link href="https://cdn.bootcss.com/webuploader/0.1.1/webuploader.css" rel="stylesheet">
    <link href="https://cdn.bootcss.com/twitter-bootstrap/4.3.1/css/bootstrap.min.css" rel="stylesheet">
    <script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>

    <script type="text/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!!!");
                        }
                    }
                }
            });
        }
    </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>

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。

后台代码:

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;

namespace WebApplication2.Controllers
{
    public class UploadController : 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(@"D:\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);
                        fs.Close();
                    });
                }
                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(@"D:\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(@"D:\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;
        }


    }
}

 这里的思路就是先保存每一个分块的文件到一个临时文件夹,

最后再通过FileStream合并这些临时文件(合并时必需要按顺序)。

后台的方法都进行了异步化(async await真的非常好用),

虽然不知道对效率有没有提升,但是就是觉得这样很酷。

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转载自www.cnblogs.com/fger/p/11293277.html