利用Blob类将file转成二进制文件流，利用window.URL.createObjectURL生成下载链接,a标签下载到本地

<template>
  <div>
    <input type="file" ref="file" @change="uploadFile($event)" />
  </div>
</template>

<script>
export default {
  props: {},
  data() {
    return {
      file: "",
    };
  },
  methods: {
    uploadFile(v) {
      console.log(v);
      this.file = v.target.files[0];
      console.log(this.file);
      let blob = new Blob([this.file],{type:"application/vnd.ms-excel;charset=utf-8"});
      console.log(blob);
      let downloadElement = document.createElement("a");
      //downloadElement.download = '文件名'
      let href = window.URL.createObjectURL(blob);
      downloadElement.href = href;
      downloadElement.download = '你所起的文件名';
      document.body.appendChild(downloadElement);
      downloadElement.click();
      document.body.removeChild(downloadElement); //移除元素；防止连续点击创建多个a标签
      window.URL.revokeObjectURL(href);
    },
  },
  components: {},
  created() {},
};
</script>

<style scoped></style>