异步下载文件-html

function asyncExportExcel(fileId){
            var loadIndex = '';
            var url = jsResPath + "partFileRecord/downloadComResult?fileId="+fileId;  //下载文件路径
            var xhr=null;
            try {
                xhr=new XMLHttpRequest()
            }catch(e) {
                xhr=new ActiveXObject("Microsoft.XMLHTTP")
            }
            //显示正在下载
            loadIndex = layer.load(2, {
                shade: [0.5, 'gray'], //0.5透明度的灰色背景
                content: '下载中...',
                success: function (layero) {
                    layero.find('.layui-layer-content').css({
                        'padding-top': '39px',
                        'width': '60px'
                    });
                }
            });
            xhr.open('POST', url, true);
            xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
            xhr.responseType = "blob"; // 返回类型blob
            // 定义请求完成的处理函数，请求前也可以增加加载框/禁用下载按钮逻辑
            xhr.onload = function () {
                // 请求完成
                if (this.status === 200) {//返回200
                    //从响应头中获取filename
                    var filename =  this.getResponseHeader('filename');
                    //解码
                    filename =decodeURI(filename);
                    var blob = this.response;
                    var reader = new FileReader();
                    reader.readAsDataURL(blob);    //转换为base64，可以直接放入a表情href
                    reader.onload = function (e) {
                        // 转换完成，创建一个a标签用于下载
                        var a = document.createElement('a');
                        a.download = filename; //下载的文件名
                        a.href = e.target.result;
                        $("body").append(a); //修复firefox中无法触发click
                        a.click();
                        $(a).remove();
                        //关闭正在下载
                        layer.close(loadIndex);
                    }
                }else {
                    layer.msg("下载失败!");
                }

            };
            //发送ajax请求
            xhr.send();

        }

后台接口：

@RequestMapping("/downloadInspectResult")
    public void downloadInspectResult(HttpServletResponse response,HttpServletRequest request){
        try{
            long fileId = Long.valueOf(request.getParameter("fileId"));
            PartFileOriginal partFileOriginal = partFileOriginalService.queryRecordById(fileId);
            XSSFWorkbook workbook = new XSSFWorkbook();
            //1-下载原始编码检查结果
            Sheet sheet = workbook.createSheet("10号检查(原始编码)");
            downloadDataService.downloadOriginalCodeInspect(fileId,sheet);
            String filename = partFileOriginal.getFileName();
            //2-下载与6.0比对的结果
            Sheet sheet1 = workbook.createSheet("与6.0比对的结果");
            downloadDataService.downloadOriginalCodeSixDb(fileId,sheet1);
            //3-下载标准编码比对的结果
            Sheet sheet2 = workbook.createSheet("标准编码比对结果");
            downloadDataService.downloadCriterionCodeInspect(fileId,sheet2 );
            //4-下载备注中包含左右，与配件标准名称做对比，若两则备注中包含的左右与标准名称中包含的左右是否一致，不一致提取出来。
            Sheet sheet3 = workbook.createSheet("备注中的左右比对结果");
            downloadDataService.downloadLeftRightInspect(fileId,sheet3);
            response.setContentType("application/force-download");
            response.setHeader("Content-Disposition", "attachment;filename=" + java.net.URLEncoder.encode(filename, "UTF-8") + ".xlsx");
        response.setHeader("filename",  java.net.URLEncoder.encode(filename, "UTF-8") + ".xlsx");
            workbook.write(response.getOutputStream());
            response.getOutputStream().close();
        }catch (Exception e){
            LogUtils.error("/dataDeal%downloadPartModel===",e);
        }

    }