var queryParams = {"test":"xxx"};
var url = "xxx";
$.ajax({
 type : "POST", //提交方式
 url : url,//路径
 contentType: "application/json",
 data: JSON.stringify(queryParams),
 beforeSend: function (request) {
  request.setRequestHeader("Authorization", "xxx");
 },
 success : function(result) {
  const blob = new Blob([result], {type:"application/vnd.ms-excel"});
  if(blob.size < 1) {
   alert('导出失败，导出的内容为空！');
   return
  }
  if(window.navigator.msSaveOrOpenBlob) {
   navigator.msSaveOrOpenBlob(blob, 'test.xls')
  } else {
   const aLink = document.createElement('a');
   aLink.style.display = 'none';
   aLink.href = window.URL.createObjectURL(blob);
   aLink.download = 'test.xls';
   document.body.appendChild(aLink);
   aLink.click();
   document.body.removeChild(aLink);
  }
 }
});

import cn.afterturn.easypoi.excel.ExcelExportUtil;
import cn.afterturn.easypoi.excel.entity.ExportParams;

@PostMapping(value = "/download")
public void downloadList(@RequestBody Objct obj, HttpServletResponse response) {

 ......

 List<Custom> excelList = new ArrayList<>();
 
   // excel总体设置
   ExportParams exportParams = new ExportParams();
   // 指定sheet名字
   exportParams.setSheetName("test");
   Workbook workbook = ExcelExportUtil.exportExcel(exportParams, Custom.class, excelList);
 
   response.setContentType("application/vnd.ms-excel");
   response.addHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode("test", "utf-8") + ".xls");
   OutputStream outputStream = response.getOutputStream();
   workbook.write(outputStream);
   outputStream.flush();
   outputStream.close();
   
 ......
 
}

var xhr = new XMLHttpRequest();
xhr.responseType = "arraybuffer"; 
xhr.open("POST", url, true);
xhr.onload = function () {
 const blob = new Blob([this.response], {type:"application/vnd.ms-excel"});
 if(blob.size < 1) {
  alert('导出失败，导出的内容为空！');
  return;
 }
 if(window.navigator.msSaveOrOpenBlob) {
  navigator.msSaveOrOpenBlob(blob, 'test.xls')
 } else {
  const aLink = document.createElement('a');
  aLink.style.display = 'none';
  aLink.href = window.URL.createObjectURL(blob);
  aLink.download = 'testxls';
  document.body.appendChild(aLink);
  aLink.click();
  document.body.removeChild(aLink);
  return;
 }
}
xhr.setRequestHeader("Authorization", "xxx");
xhr.setRequestHeader("Content-Type", "application/json");
xhr.send(JSON.stringify(queryParams));