<el-upload
  class="upload-demo"
  action="https://jsonplaceholder.typicode.com/posts/"
  multiple
  :auto-upload="false"
  :file-list="fileList"
  :on-change="fileChange">
  <el-button type="primary">导入</el-button>
</el-upload>

fileChange(file,fileList){
  console.log(file,'file')
  console.log(fileList,'fileList')
}

fileChange(file,fileList){
  console.log(file,'file')
  console.log(fileList,'fileList')
  let url = 'xxx'  //后端服务器API
  let headers = {
    'Content-Type':'multipart/form-data'   //自定义上传时，该请求头参数必填
  }
  let formData = ''
  for(let i = 0;i < fileList.length;i++){  //遍历文件数组，fileList有可能存在多个文件
    formData = new FormData()
    formData.append('name',fileList[i].name)
    formData.append('type','.xlsx')
    formData.append('file',fileList[i].raw)
  }
  this.$axios({
    headers: headers,
    method: 'post',
    data: formData,
    url: url,
    responseType:'blob'   //该参数必填，不然下载下来的excel表会提示文件损坏，无法打开
  }).then(res=>{
    if(res && res.data.size == 0){
      //若后台不返回流，说明全部数据导入成功，提示“导入成功”，不自动下载
      return
    }
    //如果后台返回流，说明部分数据导入失败，则自动下载导入失败数据的excel表
    let name = '导入失败数据.xlsx'     //自定义下载excel表名
    let blob = new Blob([res.data])
    let url = window.URL.createObjectURL(blob)
    let aLink = document.createElement('a')
    aLink.style.display = 'none'
    aLink.href = url
    //download 属性定义了下载链接的地址。href 属性必须在 <a> 标签中指定。
    aLink.setAttribute('download',name) 
    document.body.appendChild(aLink)
    aLink.click()
    document.body.removeChild(aLink)
    window.URL.revokeObjectURL(url)
    //下载结束之后可以执行其他操作，如刷新列表、友好提示等
  })
}