element+vue 文件上传downloadFile

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import axios from 'axios'
import { getToken } from '@/utils/auth'

const mimeMap = {
  xlsx: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
  zip: 'application/zip',
  exe: "application/octet-stream",
  xls: "application/vnd.ms-excel",
  json: "application/json",
  xml: "application/xml",
  docx: "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
  jpe: "image/jpeg",
  jpeg: "image/jpeg",
  jpg: "image/jpeg",
  jpg: "image/png"
}

const baseUrl = process.env.VUE_APP_BASE_API
export function downloadFile(str, fileName) {
  var url = baseUrl + str
  axios({
    method: 'get',
    url: url,
    responseType: 'blob',
    headers: { 'Authorization': getToken() }
  }).then(res => {
    resolveBlob(res, fileName,getFileMimeType(fileName))
  })
}
/**
 * 解析blob响应内容并下载
 * @param {*} res blob响应内容
 * @param {String} mimeType MIME类型
 */
export function resolveBlob(res, fileName,mimeType) {
  const aLink = document.createElement('a')
  var blob = new Blob([res.data], { type: mimeType })
  // //从response的headers中获取filename, 后端response.setHeader("Content-disposition", "attachment; filename=xxxx.docx") 设置的文件名;
  if(!fileName) {
    var patt = new RegExp('filename=([^;]+\\.[^\\.;]+);*')
    var contentDisposition = decodeURI(res.headers['content-disposition'])
    var result = patt.exec(contentDisposition)
    var fileName = result[1]
    fileName = fileName.replace(/\"/g, '')
  }
  aLink.href = URL.createObjectURL(blob)
  aLink.setAttribute('download', fileName) // 设置下载文件名称
  document.body.appendChild(aLink)
  aLink.click()
  document.body.appendChild(aLink)
}

export function getFileMimeType(fileName){
  var mimeType = "*/*";
  if(!fileName) {
    return mimeType;
  }
  if(fileName.indexOf(".")>-1) {
    var ext = fileName.substring(fileName.indexOf(".")+1);
    return mimeMap[ext]
  }
}