后端返回文件流，vue下载到本地

请求时需要设置responseType: “blob”,否则下载pdf文件打开会为空

下载方法代码如下：

//url请求参数
//params请求参数
//filename文件名称
export function download(url, params, filename) {
  return service
    .post(url, params, {
      transformRequest: [
        // (params) => {
        //   return tansParams(params);
        // },
      ],
      headers: {
        "Content-Type": "application/json;charset=utf-8",
        //"Content-Type": "application/x-www-form-urlencoded",
      },
      responseType: "blob",//关键
    })
    .then((data) => {
      console.log(data);
      const content = data;
      const blob = new Blob([content]);
      if ("download" in document.createElement("a")) {
        const elink = document.createElement("a");
        elink.download = filename;
        elink.style.display = "none";
        elink.href = URL.createObjectURL(blob);
        document.body.appendChild(elink);
        elink.click();
        URL.revokeObjectURL(elink.href);
        document.body.removeChild(elink);
      } else {
        navigator.msSaveBlob(blob, filename);
      }
    })
    .catch((r) => {
      console.error(r);
    });
}