1、axios默认请求头：

import axios from "axios";
import Cookies from "js-cookie";

axios.defaults.headers['Content-Type'] = 'application/json;charset=utf-8';

2、如果上传文件的话，需要修改请求头：

export function addReplacePersonnelManagement (data) {
  return request({
    url: "/examine/examination/add",
    method: "post",
    headers: {
      'content-type': 'application/x-www-form-urlencoded; charset=UTF-8'
    },
    data: data,
  });
}

 3、el-upload 组件的使用

<el-upload class="upload-demo" action="" drag multiple :auto-upload="false" :on-change="onChangeFile"
        :file-list="fileList" ref="upload" :on-remove="onRemoveFile"
        accept=".png, .jpeg, .jpg, .JPEG, .JPG, .webp, .bmp, .tif, .gif,.rar,.zip,.WORD,.Excel,.PDF,.xlsx">
        <i class="el-icon-upload"></i>
        <div class="el-upload__text">将文件拖到此处，或<em>点击上传</em></div>
      </el-upload>

 onChangeFile 的参数分别是 file 与 fileList 把fileList 赋值给 data定义的fileList，如果删除某个文件也会触发 onRemoveFile 它的参数与 onChangeFile 的一样  把最新的fileList重新赋值就行。

4、使用fromData提交

 //用formData 提交
 let formData = new FormData();

 if (fileList.length > 0) {
        for (let i = 0; i < fileList.length; i++) {
          formData.append("fileList", fileList[i].raw)
        }
      }