const fs=require('fs')
router.post('/imageUpload',upload.single('avatar'),function (req, res) {
    console.log(req.file)
    //獲取文件后綴名
    var appendName=req.file.originalname.split('.')[1]
    //fs重命名文件，第一個參數(shù)為上傳文件絕對路徑，第二個參數(shù)為相對路徑
    //第三個參數(shù)可選
    fs.rename(req.file.path,`tmp/uploads/${req.file.filename}.${appendName}`,function (err) {
        if (err) throw err
    })
    res.json({msg:'success'})
})

<div class="upload-file btn btn-sm btn-primary mb-2">
? <span><i class="fa fa-upload"></i> Upload</span>
? <input type="file" class="btn btn-sm btn-primary mb-2" (change)="fileChange($event, topic)" placeholder="Upload file" accept=".csv,.xls">
</div>

fileChange(event, topic) {
  this.topic = topic;
  const fileList: FileList = event.target.files;
  const file: File = fileList[0];
  const formData: FormData = new FormData();
  formData.append('_id', topic._id);
  formData.append('file', file, file.name);
  this.topicService.uploadMark(formData).subscribe((res) => {
    this.topic.marks = res;
    this.toast.setMessage('item import successfully.', 'success');
  }, error => console.log(error));
}

uploadMark(fileData: FormData): Observable<any> {
  return this.http.post('/api/upload', fileData);
}

export default function setRoutes(app) {
? const router = express.Router();
// file uplaod
router.route('/upload').post(uploadCtrl.uploadFile);
// Apply the routes to our application with the prefix /api
app.use('/api', router);
}

npm install multer --save
import * as path from 'path';
import * as multer from 'multer';
import TopicService from '../services/topic';
export default class UploadCtrl {
? uploadFile = (req, res) => {
? ? const topicService = new TopicService();
? ? // 獲取上傳文件
? ? const uploading = multer({
? ? ? dest: path.join(__dirname, '../public/uploads'),
? ? }).single('file'); // 這里的file是formData.append('file', file, file.name)里的名稱
? ? uploading(req, res, (err) => {
? ? ? if (err) {
? ? ? ? return console.error(err);
? ? ? }
? ? ? const topicId = req.body._id;
? ? ? const uploadFile = req.file;
? ? ? // 保存數(shù)據(jù)
? ? ? const save = async () => {
? ? ? ? const markList = await topicService.parseMark(uploadFile.path);
? ? ? ? const db = await topicService.saveDB(topicId, markList);
? ? ? ? return {
? ? ? ? ? markList: markList,
? ? ? ? ? db: db,
? ? ? ? };
? ? ? };
? ? ? save().then((result) => {
? ? ? ? res.status(200).json(result.markList);
? ? ? }, error => {
? ? ? ? console.error(error);
? ? ? });
? ? });
? }
}

npm install iconv-lite --save
import * as iconv from 'iconv-lite';
import * as Buffer from 'bufferhelper';
export default class IconvHelper {
? /**
? ?* 用于文件上傳的轉(zhuǎn)碼
? ?* @param fileStr
? ?* @returns {string}
? ?*/
? static iconv2utf8 = (fileStr) => {
? ? return iconv.decode(fileStr, 'gbk');
? }
? /**
? ?* 用于文件下載的轉(zhuǎn)碼
? ?* @param fileStr
? ?* @returns {NodeBuffer}
? ?*/
? static iconv2gbk = (fileStr) => {
? ? return iconv.encode(fileStr, 'gbk');
? }
}

parseMark = (filePath) => {
? return new Promise((resolve, reject) => {
? ? // 讀取文件內(nèi)容
? ? fs.readFile(filePath, (error, data) => {
? ? ? if (error) {
? ? ? ? return reject(error);
? ? ? }
? ? ? const text = IconvHelper.iconv2utf8(data);
? ? ? const markList = [];
? ? ? // 將文件按行拆成數(shù)組
? ? ? text.split(/\r?\n/).forEach((line, index) => {
? ? ? ? const arr = line.split(',');
? ? ? ? if (index > 0 && arr[0]) {
? ? ? ? ? markList.push({
? ? ? ? ? ? userId: arr[0],
? ? ? ? ? ? username: arr[1],
? ? ? ? ? ? donePageCount: arr[2],
? ? ? ? ? ? areaCount: arr[4],
? ? ? ? ? ? name: arr[6],
? ? ? ? ? });
? ? ? ? }
? ? ? });
? ? ? resolve(markList);
? ? });
? });
}

res.setHeader('Content-disposition', `attachment; filename='${result.name}-member.csv'`);
res.setHeader('Content-type', 'text/csv; charset=GBK');
res.end(IconvHelper.iconv2gbk(content));

const msExcelBuffer = Buffer.concat([
? new Buffer('\xEF\xBB\xBF', 'binary'),
? new Buffer(IconvHelper.iconv2gbk(content))
]);

res.end(IconvHelper.iconv2gbk(content));