1.在请求头加上

responseType: 'blob',

2.接口返回数据处理

const blob = new Blob([res]);
const objectURL = URL.createObjectURL(blob);
let btn = document.createElement('a');
btn.download = '文件.xls';
btn.href = objectURL;
btn.click();
URL.revokeObjectURL(objectURL);
btn = null;