getdownload() {
        let downloadParams = {
          productCode: productcode,
          reportId: reportId,
          startTime: startTime,
          endTime: endTime
        };
        reportApi.reportResultExport(downloadParams).then(res=>{
           let blob =new Blob([res.data],{type:"application/vnd.ms-excel;charset=utf-8"});
           if(window.navigator.msSaveBlob){
             window,navigator.msSaveBlob(blob,this.reportName+".xls");
           }else{
             let url = window.URL.createObjectURL(blob);
             let link = document.createElement("a");
             link.style.display = 'none';
             link.href = url;
             link.download = this.reportName+".xls";
             document.body.appendChild(link);
             link.click();
             document.body.removeChild(link);
           }
           console.log(typeof (res.data));

         }).catch(err=>{
          console.log(err);
        })
      },

请求接口

/**
 * 下载
 * @param data
 */
export function reportResultExport(data) {
  return request({
    url: '/api/v1/rpt/reportResultExport',
    method: 'post',
    data,
    code: "v4-000",
    responseType: 'blob'
  })
}

注意

service.interceptors.response.use(
  response => {

    if(response.config.responseType=='blob'){
      if(response.status==200){
        return response;
      }else{
        return Promise.reject(error);
      }
    }else{
      const res = response.data;
      if (res.code === 200) {
        return response.data

      } else if(res.code === 407){
        // console.log("Token失效跳转登陆页面");
        // sessionStorage.clear();
        // location.href="/ecloud-sp/logout";
      } else {
        Message({
          message: res.message,
          type: 'error',
          duration: 5 * 1000
        })
        return Promise.reject('error')
      }
    }

  },
  error => {
    console.log('err' + error) // for debug

    // if (axios.isCancel(error)) {
    //   // 为了终结promise链 就是实际请求 不会走到.catch(rej=>{});这样就不会触发错误提示之类了。
    //   return new Promise(() => {});
    // } else {
    Message({
      message: error.message,
      type: 'error',
      duration: 5 * 1000
    })
    return Promise.reject(error)
    // }

  }
)

在做下载excel的时候，一定要在response 拦截器判断responseType，有可能后台返回的数据流就是res