getReport(str).then(res=>{
let blob = new Blob([res], {type: 'data:application/vnd.ms-excel;base64;charset=utf-8'});
let downloadElement = document.createElement('a');
let href = window.URL.createObjectURL(blob); //创建下载的链接
downloadElement.href = href;
downloadElement.download = this.list[val-1]+'.xlsx'; //下载后文件名
document.body.appendChild(downloadElement);
downloadElement.click(); //点击下载
document.body.removeChild(downloadElement); //下载完成移除元素
window.URL.revokeObjectURL(href); //释放掉blob对象
return true
})