.Net Core MVC超大文件上传

后端控制器：
//用于保存的文件夹
    static readonly string uploadFolder = "UploadFolder";
    //目录分隔符，兼容不同系统
    static readonly char dirSeparator = Path.DirectorySeparatorChar;

    string GetTmpChunkDir(string fileName) => HttpContext.Session.TryGetValue(fileName, out byte[] bytes) ? Encoding.Default.GetString(bytes) : "";

    //[UnifyResult(typeof(JsonResult))]
    //保存文件
    [HttpPost]
    public async Task<JsonResult> SaveChunkFile(IFormFile chunk, string fileName, int chunkIndex, int chunkCount)
    {
        try
        {
            if (chunk.Length == 0)
            {
                return Json(new {
                    success = false,
                    msg = "File Length 0",
                });
            }

            if (chunkIndex == 0)
            {
                //第一次上传时，生成一个随机id,做为保存块的临时文件夹，记录到session
                HttpContext.Session.Set(fileName, Encoding.Default.GetBytes(Guid.NewGuid().ToString("N")));
            }

            if (!Directory.Exists(uploadFolder))
                Directory.CreateDirectory(uploadFolder);

            var fullChunkDir = uploadFolder + dirSeparator + GetTmpChunkDir(fileName);
            if (!Directory.Exists(fullChunkDir))
                Directory.CreateDirectory(fullChunkDir);


            var blob = chunk.FileName;
            var newFileName = blob + chunkIndex + Path.GetExtension(fileName);
            var filePath = fullChunkDir + Path.DirectorySeparatorChar + newFileName;

            //保存文件块
            using (var stream = new FileStream(filePath, FileMode.Create))
            {
                await chunk.CopyToAsync(stream);
            }


            //所有块上传完成
            if (chunkIndex == chunkCount - 1)
            {
                //也可以在这合并，在这合并就不用ajax调用CombineChunkFile合并
                //CombineChunkFile(fileName);
            }

            var obj = new {
                success = true,
                date = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss"),
                newFileName,
                originalFileName = fileName,
                size = chunk.Length,
                nextIndex = chunkIndex + 1,
            };

            return Json(obj);
        }
        catch (Exception ex)
        {
            return Json(new {
                success = false,
                msg = ex.Message,
            });
        }
    }

    [UnifyResult(typeof(JsonResult))]
    //合并文件
    public async Task<JsonResult> CombineChunkFile(string fileName)
    {
        try
        {
            return await Task.Run(() =>
            {
                var tmpDir = GetTmpChunkDir(fileName);
                var fullChunkDir = uploadFolder + dirSeparator + tmpDir;

                var beginTime = DateTime.Now;
                var newFileName = tmpDir + Path.GetExtension(fileName);
                var destFile = uploadFolder + dirSeparator + newFileName;
                //获取临时文件夹内的所有文件块，排好序
                var files = Directory.GetFiles(fullChunkDir).OrderBy(x => x.Length).ThenBy(x => x).ToList();
                using (var destStream = System.IO.File.OpenWrite(destFile))
                {
                    files.ForEach(chunk =>
                    {
                        using (var chunkStream = System.IO.File.OpenRead(chunk))
                        {
                            chunkStream.CopyTo(destStream);
                        }

                        System.IO.File.Delete(chunk);

                    });
                    Directory.Delete(fullChunkDir);
                }

                var totalTime = DateTime.Now.Subtract(beginTime).TotalSeconds;
                return Json(new {
                    success = true,
                    destFile = destFile.Replace('\\', '/'),
                    msg = $"combine completed ! {totalTime} s",
                });
            });

        }
        catch (Exception ex)
        {
            return Json(new {
                success = false,
                msg = ex.Message,
            });
        }
        finally
        {
            HttpContext.Session.Remove(fileName);
        }
    }

本人用的百小僧MVC框架
前端视图代码:
@{
    ViewData["Title"] = "Home Page";
}

<div class="text-center">
    <div>
        <input type="file" id="file1" value="" />
        <input type="button" id="btnUplaod" value="Upload" multiple="multiple" />
    </div>
    <div id="completedChunks"></div>
    <div id="percent">0%</div>
    <div id="progress" style="width:200px;height:10px;background:linear-gradient(45deg, #ff0084  0%, #e8c5d7 0%);"></div>
    @section Scripts{
    <script src="~/lib/vue/axios.min.js"></script>
        <script>
            //important
            //slice()函数要IE10+才支持。
            //Firefox 12及更早版本的使用mozSlice()
            //Safari使用webkitSlice()
            $(function () {
                {
                    var pause = false;//是否暂停
                    var $file;
                    var $fileInput;//file input
                    var $completedChunks = $('#completedChunks');//上传完成块数
                    var $progress = $('#progress');//上传进度条
                    var $percent = $('#percent');//上传百分比
                    var MiB = 1024 * 1024;
                    var chunkSize = 8.56 * MiB;//xx MiB
                    var chunkIndex = 0;//上传到的块
                    var $btnUpload = $('#btnUplaod');
                    var totalSize;//文件总大小
                    var totalSizeH;//文件总大小M
                    var chunkCount;//分块数
                    var fileName;//文件名

                    $btnUpload.click(function () {

                        var val = $.trim($(this).val());
                        if (val === 'Upload') {
                            $fileInput = $('#file1');
                            $file = $fileInput[0].files[0];

                            if ($file === undefined) {
                                $completedChunks.html('please select a file !');
                                return false;
                            }

                            totalSize = $file.size;
                            chunkCount = Math.ceil(totalSize / chunkSize * 1.0);
                            totalSizeH = (totalSize / MiB).toFixed(2);
                            fileName = $file.name;

                            val = 'Pause';
                            pause = false;
                            chunkIndex = 0;
                        }
                        else if (val === 'Pause') {
                            val = 'Resume';
                            pause = true;
                        }
                        else if (val === 'Resume') {
                            val = 'Pause';
                            pause = false;
                        }
                        else {
                            val = '-';
                        }

                        $(this).val(val);
                        postChunk();
                    });

                    function postChunk() {

                        if (pause)
                            return false;

                        var isLastChunk = chunkIndex === chunkCount - 1;
                        var fromSize = chunkIndex * chunkSize;
                        var chunk = !isLastChunk ? $file.slice(fromSize, fromSize + chunkSize) : $file.slice(fromSize, totalSize);

                        var fd = new FormData();
                        fd.append('chunk', chunk);
                        fd.append('chunkIndex', chunkIndex);
                        fd.append('chunkCount', chunkCount);
                        fd.append('fileName', fileName);
                        fd.append('__RequestVerificationToken', $("input[name=__RequestVerificationToken]").val());

                        
                        $.ajax({
                            url: '/HtAdmin/Upload/SaveChunkFile',
                            type: 'POST',
                            data: fd,
                            cache: false,
                            contentType: false,
                            processData: false,
                            success: function (d) {
                                if (!d.success) {
                                    $completedChunks.html(d.msg);
                                    return false;
                                }

                                chunkIndex = d.nextIndex;

                                if (isLastChunk) {
                                    $completedChunks.html('combining .. ');
                                    $btnUpload.val('Upload').prop('disabled', true);

                                    //合并文件
                                    $.post('/HtAdmin/Upload/CombineChunkFile', { fileName: fileName }, function (d) {
                                        $completedChunks.html(d.msg);
                                        $completedChunks.append('destFile: ' + d.destFile);
                                        $btnUpload.val('Upload').prop('disabled', false);
                                        $fileInput.val('');//清除文件
                                    });
                                }
                                else {
                                    postChunk();//递归上传文件块
                                    //$completedChunks.html(chunkIndex + '/' + chunkCount );
                                    $completedChunks.html((chunkIndex * chunkSize / MiB).toFixed(2) + 'M/' + totalSizeH + 'M');
                                }

                                var completed = chunkIndex / chunkCount * 100;
                                $percent.html(completed.toFixed(2) + '%').css('margin-left', parseInt(completed / 100 * $progress.width()) + 'px');
                                $progress.css('background', 'linear-gradient(to right, #ff0084 ' + completed + '%, #e8c5d7 ' + completed + '%)');
                            },
                            error: function (ex) {
                                $completedChunks.html('ex:' + ex.responseText);
                            }
                        });
                        
                    }
                }
            });
        </script>
    }
</div>