实现自定义表头之导出功能（使用 SXSSFWorkbook ）

导出 不使用模板

效果展示

代码展示：

    public AjaxResult exportTableData(UserColumn userColumn) {
//        获取总列数
        List<UserColumn> userColumns = userColumnMapper.getCloumn(userColumn);


        try {
            //开始创建excel
            SXSSFWorkbook workBook = new SXSSFWorkbook();
            //加粗、垂直
            CellStyle boldStyle = workBook.createCellStyle();
            Font font = workBook.createFont();
            font.setBold(true);
            boldStyle.setFont(font);

            //加边框
            CellStyle boldLeftStyle = workBook.createCellStyle();
            boldLeftStyle.setBorderBottom(BorderStyle.MEDIUM); //下边框
            boldLeftStyle.setBorderLeft(BorderStyle.MEDIUM);//左边框
            boldLeftStyle.setBorderTop(BorderStyle.MEDIUM);//上边框
            boldLeftStyle.setBorderRight(BorderStyle.MEDIUM);//右边框


            //头部颜色
            CellStyle headStyle = workBook.createCellStyle();
            headStyle.setFillForegroundColor(IndexedColors.ROYAL_BLUE.getIndex());//设置单元格的背景颜色
            headStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);//填充单元格
            headStyle.setWrapText(true);// 指定当单元格内容显示不下时自动换行

            Font fontTxt = workBook.createFont();
            fontTxt.setColor(HSSFColor.WHITE.index);
            fontTxt.setFontHeightInPoints((short) 18);
            fontTxt.setFontName("微软雅黑");

            //垂直、加粗、居中
            CellStyle centerStyle = workBook.createCellStyle();
            Font center_font = workBook.createFont();
            center_font.setBold(true);
            centerStyle.setFont(center_font);
            //centerStyle.setAlignment(CellStyle.ALIGN_CENTER);
            centerStyle.setAlignment(HorizontalAlignment.CENTER);
            //centerStyle.setVerticalAlignment(CellStyle.VERTICAL_CENTER);
            centerStyle.setVerticalAlignment(VerticalAlignment.CENTER);
    //        设置sheet
            Sheet sheet = workBook.createSheet("个性化报表");
    //设置总列
            for (int z = 0; z < userColumns.size(); z++) {
                sheet.setColumnWidth(z, 5500);
            }
    //设置第一行
            Row row0 = sheet.createRow(0);
            row0.setHeight((short) 1000);
    //第一行第一列
            row0.createCell(0).setCellStyle(headStyle);
            //第一行第二列
            Cell cell = row0.createCell(1);
            String head = "上海XXX股份有限公司上海分公司" + "\r\n" + "China Telecom Corporation Limited Shanghai Branch";
            cell.setCellValue(head);
            headStyle.setFont(fontTxt);
            cell.setCellStyle(headStyle);
            //合并单元格CellRangeAddress有4个参数：起始行号，终止行号， 起始列号，终止列号
            sheet.addMergedRegion(new CellRangeAddress(0, 0, 1, userColumns.size()-1));
            //向excel中插入logo图片
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            String picPaht = "C:\\Users\\Bt_202003\\Desktop\\202210\\fsdownloadtempFile\\heng.png";
            File imageFile = new File(picPaht);
            BufferedImage bi = ImageIO.read(imageFile);
            ImageIO.write(bi, "png", baos);
            Drawing drawing = sheet.createDrawingPatriarch();
            XSSFClientAnchor anchor = new XSSFClientAnchor(0, 0, 0, 0, 0, 0, 1, 1);
            drawing.createPicture(anchor, workBook.addPicture(baos.toByteArray(), SXSSFWorkbook.PICTURE_TYPE_JPEG));
            //设置第二行
            Row row1 = sheet.createRow(1);
//            设置列
            for (int i = 0; i < userColumns.size(); i++) {
                cell = row1.createCell(i);
                cell.setCellValue(userColumns.get(i).getFieldName());
                cell.setCellStyle(boldLeftStyle);
            }

//            填充表数据
            List<KcExcelTable> tables = mapper.getData(userColumns.get(0).getTaskId());

            for (int i = 0; i < tables.size(); i++) {
                KcExcelTable kcExcelTable1 = tables.get(i);
//                创建行
                Row row = sheet.createRow((i + 2));

                for (int j = 0; j < userColumns.size(); j++) {
                    String entityName = userColumns.get(j).getEntityName();
                    //通过传入实体类字段名，获取字段值方法
                    if (null == (kcExcelTable1.get(entityName))) {
                        cell = row.createCell(j);
                        cell.setCellValue("");
                        if (!(null == kcExcelTable1.get(entityName))) {
                            cell.setCellStyle(boldLeftStyle);
                        }
                    } else {
                        cell = row.createCell(j);
                        cell.setCellValue(kcExcelTable1.get(entityName));
                        cell.setCellStyle(boldLeftStyle);
//                        cell.setCellStyle(boldStyle);
                    }
                }

            }

//            创建写入文件流
            OutputStream os = null;

//        // 创建这个文件夹
//        try {
//            File execlSaveFile = new File(exportUrl);
//            if (!execlSaveFile.exists()) {
//                execlSaveFile.mkdirs();
//            }
//        } catch (Exception e) {
//            e.printStackTrace();
//        }

//            导出地址
            String exportUrl = "C:/Users/Bt_202003/Desktop/202210/fsdownload" + FileUtils.getTempPath() + "excel导出" + UUID.randomUUID().toString() + ".xlsx";
            FileUtils.createFile(exportUrl);//创建文件
            //写入文件
            try {
                os = new FileOutputStream(exportUrl);
                workBook.write(os);
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (null != os) {
                    os.close();
                }
            }

        } catch (IOException e) {
            e.printStackTrace();
        }

        return AjaxResult.success("导出成功");
    }

```java
//数据表实体类，通过传入实体类字段名，获取字段值方法
    public String get(String name){
        String str = "";
        //如果传入的实体类名字与case里面的字符串相等，则调用相应的get方法获取值。
        switch (name){
            case "deviceNo":
                str =  getDeviceNo();
                break;
            case "billingCycle":
                str =  getBillingCycle();
            break;
        }
        return str;
    }