getDownload(urls, fileName) {

             var url = urls;

             var xhr = new XMLHttpRequest();

             xhr.open("get", url, true);

             xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");

             xhr.setRequestHeader("access-token", store.state.token.token);

             xhr.send();

             xhr.responseType = "blob"; // 返回类型blob

             xhr.onload = function() {

                 if (this.status === 200) {

                     let a = document.createElement("a");

                     let blob = new Blob([this.response], {

                         type: "text/csv;charset=GBK;"

                     });

                     let objectUrl = URL.createObjectURL(blob);

                     a.setAttribute("href", objectUrl);

                     a.setAttribute("download", fileName + ".csv");

                     a.click();

                 } else {

                     alert("出现了未知的错误!");

                 }

             };

         },