const router = require('koa-router')()
const multer = require('koa-multer')

router.prefix('/upload')

//配置
var storage = multer.diskStorage({
        //文件保存路径
        destination: function(req, file, cb) {
        //存储目录是手动建的 好像没办法自动建立二级目录
            cb(null, './public/uploads/')
        },
        //修改文件名称
        filename: function(req, file, cb) {
            var fileFormat = (file.originalname).split(".");
            cb(null, Date.now() + "." + fileFormat[fileFormat.length - 1]);
        }
    })
    //加载配置
var upload = multer({ storage: storage });
//路由
router.post('/uploadimage', upload.single('file'), async(ctx, next) => {
    ctx.body = {
        fileData: ctx.req.file,
    }
})
module.exports = router

前端页面 是用elementui 的上传组件

  <el-upload
            class="avatar-uploader"
             //上传的地址
            action="http://127.0.0.1:3000/upload/uploadimage"
            :show-file-list="false"
             //需要的请求头
            :headers="headers"
            :on-success="handleAvatarSuccess"
            :before-upload="beforeAvatarUpload"
          >
            <img v-if="imageUrl" :src="imageUrl" class="avatar" />
            <i v-else class="el-icon-plus avatar-uploader-icon"></i>
  </el-upload>

JS

//设置请求头
 computed: {
    headers() {
      return {
        Authorization: "Bearer " + localStorage.getItem("token"),
      };
    },
  },