上传头像并预览,在整体保存时再上传数据

<el-form-item label="客户默认头像">
  <el-upload
     class="user-head-uploader headImg-uploader"
     accept=".jpg,.jpeg,.png,.gif,.JPG,.JPEG"
     action="#"
     :show-file-list="false"
     :on-change="handleUserHeadImgChange"
     :before-upload="beforeHandleUserUpload"
     :http-request="httpRequestUser">
     <img class="userHeadImg headImg" :src="appAccessForm.userHeadImg" alt="">
     <el-button plain size="mini">选择文件</el-button>
   </el-upload>
 </el-form-item>

 httpRequestUser (param) {
   console.log('httpRequestUser', param)
   this.appAccessForm.userHeadImg = URL.createObjectURL(param.file)
 },