如何在.NET WebForm中实现能源化工行业的大文件分片断点续传？

大文件传输系统技术方案

作为江苏某软件公司的技术负责人，在处理公司产品部门提出的大文件传输需求时，我经过详细调研和评估，提出以下技术方案：

需求分析与技术挑战

当前需求面临的主要技术挑战包括：

超大文件传输：50GB以上文件的高效可靠传输
断点续传稳定性：浏览器刷新/关闭后不丢失进度
文件夹结构保留：完整保持原始文件夹层级关系
多平台兼容性：支持Windows 7+IE8等老旧环境
系统集成要求：与现有.NET Core+Vue3技术栈无缝整合

技术选型与架构设计

后端架构 (.NET Core)

// 文件分片上传控制器示例[ApiController][Route("api/upload")]publicclassFileUploadController:ControllerBase{privatereadonlyIFileService_fileService;publicFileUploadController(IFileServicefileService){_fileService=fileService;}[HttpPost("init")]publicasyncTaskInitUpload([FromBody]UploadInitRequestrequest){// 初始化上传会话，生成唯一IDvarsession=await_fileService.InitUploadSessionAsync(request.FileName,request.FileSize,request.FolderStructure);returnOk(new{sessionId=session.Id,chunkSize=session.ChunkSize});}[HttpPost("chunk/{sessionId}")]publicasyncTaskUploadChunk(stringsessionId,[FromForm]IFormFilechunk,[FromForm]intchunkIndex){await_fileService.SaveChunkAsync(sessionId,chunkIndex,chunk.OpenReadStream());returnOk();}[HttpPost("complete/{sessionId}")]publicasyncTaskCompleteUpload(stringsessionId){varfileInfo=await_fileService.CompleteUploadAsync(sessionId);returnOk(fileInfo);}}

前端实现 (Vue3)

// 文件上传组件示例exportdefault{data(){return{fileList:[],uploadSessions:{},chunkSize:5*1024*1024// 5MB分片}},methods:{asynchandleUpload(files){for(constfileoffiles){constsessionId=awaitthis.initUploadSession(file)this.uploadSessions[sessionId]={file,uploadedChunks:newSet(),sessionId}awaitthis.uploadFileInChunks(sessionId)}},asyncinitUploadSession(file){constresponse=awaitapi.post('/api/upload/init',{fileName:file.name,fileSize:file.size,folderStructure:file.webkitRelativePath||''})returnresponse.data.sessionId},asyncuploadFileInChunks(sessionId){constsession=this.uploadSessions[sessionId]constchunkCount=Math.ceil(session.file.size/this.chunkSize)// 恢复已上传的分片constprogress=awaitthis.checkUploadProgress(sessionId)session.uploadedChunks=newSet(progress.uploadedChunks)for(leti=0;i<chunkCount;i++){if(!session.uploadedChunks.has(i)){awaitthis.uploadChunk(session,i)session.uploadedChunks.add(i)// 保存进度到本地存储this.saveProgressToStorage(sessionId,Array.from(session.uploadedChunks))}}awaitthis.completeUpload(sessionId)},asyncuploadChunk(session,chunkIndex){conststart=chunkIndex*this.chunkSizeconstend=Math.min(start+this.chunkSize,session.file.size)constchunkBlob=session.file.slice(start,end)constformData=newFormData()formData.append('chunk',chunkBlob,`chunk-${chunkIndex}`)formData.append('chunkIndex',chunkIndex)awaitapi.post(`/api/upload/chunk/${session.sessionId}`,formData,{onUploadProgress:progressEvent=>{constpercent=Math.round((progressEvent.loaded/progressEvent.total)*100)this.$emit('progress',{sessionId:session.sessionId,chunkIndex,percent})}})}}}

核心技术实现

1. 断点续传持久化方案

// 断点续传状态存储服务publicclassUploadSessionService:IUploadSessionService{privatereadonlyAppDbContext_dbContext;publicUploadSessionService(AppDbContextdbContext){_dbContext=dbContext;}publicasyncTaskInitSessionAsync(stringfileName,longfileSize,stringfolderPath){varsession=newUploadSession{Id=Guid.NewGuid().ToString(),FileName=fileName,FileSize=fileSize,FolderPath=folderPath,ChunkSize=5*1024*1024,// 5MBStatus=UploadStatus.InProgress,CreatedAt=DateTime.UtcNow,UploadedChunks=newList()};_dbContext.UploadSessions.Add(session);await_dbContext.SaveChangesAsync();returnsession;}publicasyncTaskSaveChunkAsync(stringsessionId,intchunkIndex,StreamchunkStream){// 1. 将分片保存到临时存储 (OSS/本地)vartempPath=awaitSaveChunkToTempStorage(sessionId,chunkIndex,chunkStream);// 2. 更新数据库记录varsession=await_dbContext.UploadSessions.FindAsync(sessionId);if(!session.UploadedChunks.Contains(chunkIndex)){session.UploadedChunks.Add(chunkIndex);await_dbContext.SaveChangesAsync();}}publicasyncTaskCheckChunkExistsAsync(stringsessionId,intchunkIndex){varsession=await_dbContext.UploadSessions.FindAsync(sessionId);returnsession?.UploadedChunks.Contains(chunkIndex)??false;}}

2. 文件夹结构处理

// 文件夹上传处理器publicclassFolderUploadProcessor{publicasyncTaskProcessFolderUpload(stringsessionId,stringtempFolderPath,stringtargetFolderPath){// 从数据库获取上传会话信息varsession=await_sessionService.GetSessionAsync(sessionId);// 重建文件夹结构stringfullTargetPath=Path.Combine(targetFolderPath,session.FolderPath);Directory.CreateDirectory(fullTargetPath);// 合并所有分片到最终文件stringtempFilePath=Path.Combine(tempFolderPath,sessionId,session.FileName);stringfinalFilePath=Path.Combine(fullTargetPath,session.FileName);awaitMergeChunksToFinalFile(tempFilePath,finalFilePath);// 更新会话状态为已完成await_sessionService.CompleteSessionAsync(sessionId,finalFilePath);}}

兼容性处理方案

IE8兼容性适配

// IE8兼容的XHR上传封装functionuploadChunkIE8(sessionId,chunkIndex,blob,callback){varxhr=newXDomainRequest();// IE8特定对象varformData=newFormData();formData.append('chunk',blob);formData.append('chunkIndex',chunkIndex);xhr.open('POST','/api/upload/chunk/'+sessionId);xhr.onload=function(){callback(null,xhr.responseText);};xhr.onerror=function(){callback(newError('Upload failed'));};// IE8特殊处理 - 需要将FormData转为字符串varboundary='----'+newDate().getTime();xhr.setRequestHeader('Content-Type','multipart/form-data; boundary='+boundary);varbody='';for(varpairofformData.entries()){body+='--'+boundary+'\r\n';body+='Content-Disposition: form-data; name="'+pair[0]+'"';if(typeofpair[1]==='object'){body+='; filename="'+pair[1].name+'"\r\n';body+='Content-Type: application/octet-stream\r\n\r\n';body+=pair[1].getAsBinary()+'\r\n';}else{body+='\r\n\r\n'+pair[1]+'\r\n';}}body+='--'+boundary+'--';xhr.send(body);}

部署架构建议

混合云部署方案

+-----------------------+ | Load Balancer | +-----------+-----------+ | +-----------------------+-----------------------+ | | +--------------+-----------+ +-------------+-------------+ | Public Cloud (OSS) | | Private Data Center | | | | | | +---------------------+ | | +---------------------+ | | | Frontend Servers | | | | Frontend Servers | | | +----------+----------+ | | +----------+----------+ | | | | | | | | +----------+----------+ | | +----------+----------+ | | | API Gateway (K8s) +<----------------------->+ API Gateway (K8s) | | | +----------+----------+ | | +----------+----------+ | | | | | | | | +----------+----------+ | | +----------+----------+ | | | Upload Microservice | | | | Upload Microservice | | | +----------+----------+ | | +----------+----------+ | | | | | | | | +----------+----------+ | | +----------+----------+ | | | Database (SQL) | | | | Database (SQL) | | | +---------------------+ | | +---------------------+ | | | | | +--------------------------+ +---------------------------+