一、实战整理后的代码如下

@RequestMapping("/batchExport")public void batchExport(HttpServletResponse response, String ids) {        String[] idList = ids.split(",");        /*创建Excel*/        HSSFWorkbook workbook = new HSSFWorkbook();//创建Excel文件(Workbook)        workbook.createInformationProperties();//创建文档信息        DocumentSummaryInformation dsi = workbook.getDocumentSummaryInformation();//摘要信息        dsi.setCategory("Excel文件");//类别        dsi.setManager("");//管理者        dsi.setCompany("");//公司        SummaryInformation si = workbook.getSummaryInformation();//摘要信息//        si.setSubject("");//主题        si.setTitle("");//标题        si.setAuthor("");//作者//            si.setComments("");//备注        try {            for (int i = 0, num = idList.length; i < num; i++) {                //获取数据                Listlist = contractService.listProduct(idList[i]);                Contract contract = contractService.getContract(idList[i]);                if (null!=contract) {                    HSSFSheet sheet = workbook.createSheet(idList[i]);//创建工作表(Sheet)                    HSSFRow row = sheet.createRow(0);// 创建行,从0开始                    //合并列                    HSSFCell cell = row.createCell(0);                    cell.setCellValue("标题");                    CellRangeAddress region1 = new CellRangeAddress(0, 2, 0, 7);                    sheet.addMergedRegion(region1);                    HSSFCellStyle style = workbook.createCellStyle();                    style.setBorderBottom(BorderStyle.THIN);//下边框                    style.setBorderLeft(BorderStyle.THIN);//左边框                    style.setBorderRight(BorderStyle.THIN);//右边框                    style.setBorderTop(BorderStyle.THIN); //上边框                    HSSFFont font = workbook.createFont();                    font.setFontHeightInPoints((short) 10);//设置字号//                    font.setBold(true); //加粗                    style.setFont(font);                    style.setWrapText(true);//換行                    Integer l = list.size();                    for (int j = 0; j < l; j++) {                        Product product = list.get(j);                        HSSFRow rows = sheet.createRow(8 + j);                        HSSFCell cellj1 = rows.createCell(0);                        cellj1.setCellValue(product.getProduct_name());                        HSSFCell cellj2 = rows.createCell(1);                        cellj2.setCellValue(product.getProduct_model());                        HSSFCell cellj3 = rows.createCell(2);                        cellj3.setCellValue(product.getProduct_specification());                        HSSFCell cellj4 = rows.createCell(3);                        cellj4.setCellValue(product.getProduct_unit());                        HSSFCell cellj5 = rows.createCell(4);                        cellj5.setCellValue(product.getProduct_num());                        HSSFCell cellj6 = rows.createCell(5);                        cellj6.setCellValue(product.getProduct_unit_price() + "元");                        HSSFCell cellj7 = rows.createCell(6);                        cellj7.setCellValue(product.getMoney() + "元");                        HSSFCell cellj8 = rows.createCell(7);                        cellj8.setCellValue(product.getRemark());                        cellj1.setCellStyle(style);                        cellj2.setCellStyle(style);                        cellj3.setCellStyle(style);                        cellj4.setCellStyle(style);                        cellj5.setCellStyle(style);                        cellj6.setCellStyle(style);                        cellj7.setCellStyle(style);                        cellj8.setCellStyle(style);                    }                    //轮到8+l了                    HSSFRow row8L = sheet.createRow(8 + l);                    HSSFCell cell8L_1 = row8L.createCell(0);                    cell8L_1.setCellValue("合同人民币大写金额:" + NumberToCN.number2CNMontrayUnit(new BigDecimal(contract.getContract_price())));                    CellRangeAddress region2 = new CellRangeAddress(8 + l, 8 + l, 0, 5);                    sheet.addMergedRegion(region2);                    HSSFCell cell8L_2 = row8L.createCell(6);                    cell8L_2.setCellValue(contract.getContract_price() + "元");                    CellRangeAddress region3 = new CellRangeAddress(8 + l, 8 + l, 6, 7);                    sheet.addMergedRegion(region3);                    cell8L_1.setCellStyle(style);                    cell8L_2.setCellStyle(style);                                        setRegionBorder(BorderStyle.THIN,region1,sheet);                    setRegionBorder(BorderStyle.THIN,region2,sheet);                    setRegionBorder(BorderStyle.THIN,region3,sheet);                                        sheet.setColumnWidth(0, 20 * 256);//设置第一列的宽度是20个字符宽度                    sheet.setColumnWidth(1, 13 * 256);//设置第二列的宽度是13个字符宽度                    sheet.setColumnWidth(2, 13 * 256);                    sheet.setColumnWidth(3, 8 * 256);                    sheet.setColumnWidth(4, 8 * 256);                    sheet.setColumnWidth(5, 13 * 256);                    sheet.setColumnWidth(6, 13 * 256);                    sheet.setColumnWidth(7, 13 * 256);                    row.setHeightInPoints(50);//设置行的高度是50个点                    row8L.setHeightInPoints(20);//设置行的高度是20个点                    HSSFPrintSetup ps = sheet.getPrintSetup();                    ps.setLandscape(false); // 打印方向，true：横向，false：纵向                    ps.setPaperSize(HSSFPrintSetup.A4_PAPERSIZE); //纸张                    sheet.setMargin(HSSFSheet.BottomMargin, (double) 0.5);// 页边距(下)                    sheet.setMargin(HSSFSheet.LeftMargin, (double) 0.1);// 页边距(左)                    sheet.setMargin(HSSFSheet.RightMargin, (double) 0.1);// 页边距(右)                    sheet.setMargin(HSSFSheet.TopMargin, (double) 0.5);// 页边距(上)                    sheet.setHorizontallyCenter(true);//设置打印页面为水平居中                    sheet.setVerticallyCenter(false);//设置打印页面为垂直居中使用POI输出Excel时打印页面的设置 - TOUGHGUYNEU - @EXPLORER使用POI输出Excel时打印页面的设置 - TOUGHGUYNEU - @EXPLORER                }            }            //将文件存到浏览器设置的下载位置            exportExcelByDownload(workbook, response, "批量导出Excel");        } catch (UnsupportedEncodingException e) {            e.printStackTrace();        } catch (Exception e) {            e.printStackTrace();        }    }  /**     * @Description: 解决合并单元格没有边框(边框被覆盖掉)     * @MethodName: setRegionBorder     * @Param: [border, region, sheet]     * @Return: void     * @Date: 2020-11-05    **/    private void setRegionBorder(BorderStyle border, CellRangeAddress region, Sheet sheet) {        RegionUtil.setBorderBottom(border, region, sheet);        RegionUtil.setBorderLeft(border, region, sheet);        RegionUtil.setBorderRight(border, region, sheet);        RegionUtil.setBorderTop(border, region, sheet);    }    /**     * excel表格直接下载     */    public static void exportExcelByDownload(HSSFWorkbook wb, HttpServletResponse httpServletResponse, String fileName) throws Exception {        //响应类型为application/octet- stream情况下使用了这个头信息的话，那就意味着不想直接显示内容        httpServletResponse.setContentType(MediaType.APPLICATION_OCTET_STREAM_VALUE);        //attachment为以附件方式下载        SimpleDateFormat newsdf = new SimpleDateFormat("yyyyMMddHHmmss");        String date = newsdf.format(new Date());        httpServletResponse.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(                fileName + date + ".xls",                "utf-8"));        /**         * 代码里面使用Content-Disposition来确保浏览器弹出下载对话框的时候。         * response.addHeader("Content-Disposition","attachment");一定要确保没有做过关于禁止浏览器缓存的操作         */        httpServletResponse.setHeader("Cache-Control", "No-cache");        httpServletResponse.flushBuffer();        wb.write(httpServletResponse.getOutputStream());        wb.close();    }/** * @Description: 删除rowIndex行，并且上移其它行 * @MethodName: removeRow * @Param: [sheet, rowIndex] * @Return: void * @Date: 2020-11-05**/private static void removeRow(HSSFSheet sheet, int rowIndex) {    int lastRowNum=sheet.getLastRowNum();    if(rowIndex>=0&&rowIndex        sheet.shiftRows(rowIndex+1,lastRowNum,-1);//将行号为rowIndex+1一直到行号为lastRowNum的单元格全部上移一行，以便删除rowIndex行    }    if(rowIndex==lastRowNum){        HSSFRow removingRow=sheet.getRow(rowIndex);        if(removingRow!=null)            sheet.removeRow(removingRow);    }}

js在首篇文章里说了哟

二、很不错的文章

①JAVA POI的使用_林中静月下仙的博客-CSDN博客

链接：https://blog.csdn.net/qq_21137441/article/details/79226171

②POI3切换为POI4修改内容

链接：https://blog.csdn.net/wang_cheng_/article/details/89947369

写完后，我突然感觉为什么不封装个方法，循环数组即可，内容定义在数组里。虽然我也封装了不少，算了毕竟第一次使用POI，下回再说。

三、总结：最好使用封装POI的工具(比如hutool等)去做导入导出，毕竟几行代码就能搞定，面对复杂的文件导出建议使用模板引擎。如果前者都不适用，那就选POI吧，POI功能强大，无所不能，无法无天，哈哈哈。

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