缺點就是不能設(shè)置表頭寬度且內(nèi)容不能居中

導(dǎo)出excel的邏輯：

excel整個表格專業(yè)名詞是workbook，里面每張表格是sheet
頁面引入xlsx的庫，https://unpkg.com/xlsx/dist/xlsx.core.min.js
把數(shù)據(jù)生成sheet，var sheet = XLSX.utils.json_to_sheet(jsonData)，json_to_sheet是將由對象組成的數(shù)組轉(zhuǎn)化成sheet，當(dāng)然還有 aoa_to_sheet將一個二維數(shù)組轉(zhuǎn)成sheet 和 table_to_sheet將table的dom直接轉(zhuǎn)成sheet
創(chuàng)建虛擬的workbook，var wb = XLSX.utils.book_new()
把sheet添加到workbook里，XLSX.utils.book_append_sheet(wb, sheet, "這里是sheetName");
把workbook轉(zhuǎn)成blob，var blob = workbook2blob(wb)，這里workbook2blob需要手動寫啦，下面會貼代碼
利用a標簽和createObjectURL實現(xiàn)下載功能，openDownloadDialog(blob, 'excel的標題.xlsx');，這里openDownloadDialog也會在下面放上代碼

import XLSX from "xlsx";

 //按學(xué)生統(tǒng)計
            let students = data.obj.students.map((v, i) => {
              return {
                序號: i + 1,
                學(xué)生姓名: v.studentname,
                學(xué)生賬號: v.loginname,
                所屬班級: v.classname
                  ? getGradeName(v.gradeid) + v.classname
                  : "",
                收到作業(yè)次數(shù): v.sdnum,
                提交作業(yè)次數(shù): v.commitnum,
                提交率: v.commitrate + "%",
                得分率: v.scorerate + "%"
              };
            });
            //按科目統(tǒng)計
            let subjects = data.obj.subjects.map((v, i) => {
              return {
                序號: i + 1,
                學(xué)生姓名: v.studentname,
                學(xué)生賬號: v.loginname,
                所屬班級: v.classname
                  ? getGradeName(v.gradeid) + v.classname
                  : "",
                所屬科目: v.subjectname ? v.subjectname : "",
                科目作業(yè): v.sdnum,
                已提交作業(yè): v.commitnum,
                提交率: v.commitrate + "%",
                得分率: v.scorerate + "%"
              };
            });
            const sheet1 = XLSX.utils.json_to_sheet(students);
            const sheet2 = XLSX.utils.json_to_sheet(subjects);
            const wb = XLSX.utils.book_new();
            XLSX.utils.book_append_sheet(wb, sheet1, "按學(xué)生統(tǒng)計");
            XLSX.utils.book_append_sheet(wb, sheet2, "按科目統(tǒng)計");
            const workbookBlob = this.workbook2blob(wb);
            let da = new Date(this.form_stu.starttime * 1000);
            var year = da.getFullYear() + "年";
            var month = da.getMonth() + 1 + "月";
            var date = da.getDate() + "日";
            let starttime = year + month + date;
            let das = new Date(this.form_stu.stoptime * 1000);
            var years = das.getFullYear() + "年";
            var months = das.getMonth() + 1 + "月";
            var dates = das.getDate() + "日";
            let stoptime = years + months + dates;
            let excelName = starttime + "-" + stoptime + "作業(yè)統(tǒng)計";
            // 導(dǎo)出最后的總表
            this.openDownloadDialog(workbookBlob, excelName + ".xlsx");

   workbook2blob(workbook) {
      // 生成excel的配置項
      var wopts = {
        // 要生成的文件類型
        bookType: "xlsx",
        // 是否生成Shared String Table，官方解釋是，如果開啟生成速度會下降，但在低版本IOS設(shè)備上有更好的兼容性
        bookSST: false,
        type: "binary"
      };
      var wbout = XLSX.write(workbook, wopts);
      // 將字符串轉(zhuǎn)ArrayBuffer
      function s2ab(s) {
        var buf = new ArrayBuffer(s.length);
        var view = new Uint8Array(buf);
        for (var i = 0; i !== s.length; ++i) view[i] = s.charCodeAt(i) & 0xff;
        return buf;
      }
      let buf = s2ab(wbout);
      var blob = new Blob([buf], {
        type: "application/octet-stream"
      });
      return blob;
    },
    // 將blob對象 創(chuàng)建bloburl,然后用a標簽實現(xiàn)彈出下載框
    openDownloadDialog(blob, fileName) {
      if (typeof blob === "object" && blob instanceof Blob) {
        blob = URL.createObjectURL(blob); // 創(chuàng)建blob地址
      }
      var aLink = document.createElement("a");
      aLink.href = blob;
      // HTML5新增的屬性，指定保存文件名，可以不要后綴，注意，有時候 file:///模式下不會生效
      aLink.download = fileName || "";
      var event;
      if (window.MouseEvent) event = new MouseEvent("click");
      //   移動端
      else {
        event = document.createEvent("MouseEvents");
        event.initMouseEvent(
          "click",
          true,
          false,
          window,
          0,
          0,
          0,
          0,
          0,
          false,
          false,
          false,
          false,
          0,
          null
        );
      }
      aLink.dispatchEvent(event);
    },