发布时间:2022-08-18 文章分类:编程知识 投稿人:李佳 字号: 默认 | | 超大 打印

后端服务使用的是Asp.net WebApi,至于如果有环境搭建或者怎么引入上传控件这一类的问题,请自行百度,都有手册多看几遍。
在此记录的是核心的一些代码,没有给出界面UI,因为重点是给出思路和怎么用

1.页面引入nz-upload

1.我们在Angular页面引入控件,主要介绍2个重要的属性,其他的建议读下手册

<nz-upload [nzAction]="''" [(nzFileList)]="fileList" nzMultiple [nzLimit]="0" [nzShowUploadList]="false"
  [nzBeforeUpload]="beforeUpload">
  <button [disabled]="false" nz-button nzType="primary" nz-popover nzPopoverContent="Upload File">
    <i nz-icon nzType="upload"></i>
  </button>
</nz-upload>
2.钩子事件和上传事件

1.钩子事件就是上传事件之前执行的事件,可以做一些校验等操作,当然你也可以写在上传事件中,随处可见的AOP

fileList: NzUploadFile[] = [];
beforeUpload = (file: NzUploadFile): boolean => {
    //判断文件大小
    const isLt4M = file.size! / 1024 / 1024 < 4;
    if (!isLt4M) {
      this.message.error('Message.File.SizeFile');
      return false;
    }
    this.fileList = this.fileList.concat(file);
    return true;
}

2.上传事件用于将文件信息提交到后端

async handleUpload() {
    const formData = new FormData();
    //将文件绑定到FormData中
    this.fileList.forEach((file: any) => {
      formData.append("files[]", file);
    });
    //给后端文件服务标识来源于什么系统
    formData.append("system", "OA");
    //给后端文件服务标识是什么类型的附件
    formData.append('annexType', "附件类型");
    //使用Post调用文件服务
    this.httpclient.post<any>("192.168.0.105/api/FileServer/UploadFile", formData).toPromise();  
  }
3.下载文件

1.定义下载对象,然后调用后端下载api接口


downLoadFile(file: Attachment): void {
  const DownloadRequest = {
        FileFullPath: 文件服务器摘要返回的文件路径,
        FileId: 文件服务器摘要返回的文件ID,
        FullFileName: 文件服务器摘要返回的文件名称,
  };
  let head = new HttpHeaders({ 'Content-Type': 'application/json' });
  //调用文件下载服务
  this.httpclient.post<any>("192.168.0.105/api/FileServer/DownloadFile",DownloadRequest,{ headers: head, responseType: 'arraybuffer' }).subscribe(
    (result) => {
      if ('msSaveOrOpenBlob' in navigator) {
        const nav = window.navigator as any;
        nav.msSaveOrOpenBlob(
          new Blob([]),
          DownloadRequest.FullFileName
        );
        return;
      } else {
        const url = window.URL.createObjectURL(new Blob([result]));
        const link = document.createElement('a');
        link.style.display = 'none';
        link.href = url;
        link.setAttribute('download', DownloadRequest.FullFileName);
        document.body.appendChild(link);
        link.click();
        document.body.removeChild(link);
        return url;
      }
  })
4.后端WebAPI服务
  1. 在这里实现思路为文件服务器保存文件,并生成文件一对一的摘要信息,返回到客户端,客户端收到上传成功的摘要信息,然后将摘要Id与业务数据绑定,存到业务数据库,下次加载数据,根据摘要Id来找到对应的文件信息,然后访问文件服务器下载文件。

  2. 这里暂时不考虑,如果多个文件是否完整上传,中间有失败的情况,为了服务器安全,后端和前端应适当过滤筛选出一些不能被上传的文件后缀,例如DLL exe这些,这只是个小建议,当然您可以使用,你所喜欢的任何文件服务中间件,作为你的文件服务器

3.控制器中接收文件上传内容,存入本地磁盘文件夹,然后返回文件信息的摘要包含如下

  • 文件对应生成的唯一id
  • 文件存储文件夹路径
  • 文件内容长度
  • 文件后缀名
  • 文件是否被压缩

控制器接收

[HttpPost]
[Route("api/FileServer/UploadFile")]
public HttpResponseMessage UploadFile()
{
    HttpRequest httpRequest = HttpContext.Current.Request;
    string config = httpRequest.Params["system"].Trim();
    string annexType = httpRequest.Params["annexType"].Trim();
    if (string.IsNullOrEmpty(config) || string.IsNullOrEmpty(annexType))
    {
        return Request.CreateResponse(HttpStatusCode.BadRequest, "config and annexType is required.");
    }
    string FilePath = ConfigurationManager.AppSettings[config];
    var filePath = HttpContext.Current.Server.MapPath(FilePath + annexType) + "\\";
    if (!Directory.Exists(filePath)) Directory.CreateDirectory(filePath);
    return UploadFileHandler(httpRequest,filePath);
}

文件处理方法

 [NonAction]
 public HttpResponseMessage UploadFileHandler(HttpRequest httpRequest, string filePath)
 {
     try
     {
         HttpResponseMessage result = null;
         if (httpRequest.Files.Count > 0)
         {
             //文件信息的摘要
             List<FileData> ResponseData = new List<FileData>();
             for (int i = 0; i < httpRequest.Files.Count; i++)
             {
                 FileData fileData = new FileData();
                 var postedFile = httpRequest.Files[i];
                 string guid = Guid.NewGuid().ToString().ToUpper();
                 //一个一个文件保存到本地磁盘
                 postedFile.SaveAs(filePath + guid);
                 fileData.FileId = guid;
                 fileData.FullFileName = postedFile.FileName;
                 fileData.FileFullPath = filePath + guid;
                 fileData.ContentLength = postedFile.ContentLength;
                 fileData.Extension = postedFile.FileName.Substring(postedFile.FileName.LastIndexOf('.'));
                 fileData.isZipFile = false;
                 ResponseData.Add(fileData);
             }
             result = Request.CreateResponse(HttpStatusCode.Created, ResponseData);
         }
         else
         {
             result = Request.CreateResponse(HttpStatusCode.BadRequest);
         }
         return result;
     }
     catch (Exception e)
     {
         HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.InternalServerError);
         response.ReasonPhrase = e.Message;
         return response;
     }
 }

2.下载文件服务

[HttpPost]
[Route("api/FileServer/DownloadFile")]
public HttpResponseMessage DownloadFile(DownloadRequest request)
{
    try
    {
        HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
        System.IO.FileInfo fileInfo = new System.IO.FileInfo(request.FileFullPath);
        if (!fileInfo.Exists)
        {
            response = new HttpResponseMessage(HttpStatusCode.NotFound);
            response.ReasonPhrase = "File does not exists.";
            return response;
        }
        FileStream stream = new FileStream(request.FileFullPath, FileMode.Open);
        response.Content = new StreamContent(stream);
        response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/force-download");
        response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
        {
            FileName = HttpUtility.UrlEncode(request.FullFileName)
        };
        response.Headers.Add("Access-Control-Expose-Headers", "FileName");
        response.Headers.Add("FileName", HttpUtility.UrlEncode(request.FullFileName));
        return response;
    }
    catch (Exception e)
    {
        HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.InternalServerError);
        response.ReasonPhrase = e.Message;
        return response;
    }
}