在下列方法上新增功能，第四列，第五列，第六列的合并行数以第三列的合并行数为准 public static int exportToExcelForXlsx(List<List> objData, String sheetName, List<String> columns, List mergeIndex, HttpServletResponse response) { int flag = 0; XSSFWorkbook wb = new XSSFWorkbook(); XSSFSheet sheet1 = wb.createSheet(sheetName); sheet1row1.setHeight((short) 520); if (columns != null && columns.size() > 0) { for(int i=0;i<columns.size();i++) { String column = columns.get(i); //列 XSSFCell cell = sheet1row1.createCell(i); cell.setCellValue(column); } } int dataSatrtIndex = 1; boolean isMerge = false; if(mergeIndex != null && mergeIndex.size() != 0) { isMerge = true; } if (objData != null && objData.size() > 0) { Map<Integer, PoiModel> poiModels = new HashMap<Integer, PoiModel>(); int i = 0; for ( ; i < objData.size(); i++) { XSSFRow row = sheet1.createRow((short) (i+dataSatrtIndex)); List<Object> list = objData.get(i); DecimalFormat decimalFormat = new DecimalFormat("0.00"); int j = 0; for (Object o : list) { String content = ""; if(o != null) { if (o.toString().contains(".") && isNumeric(o.to }else { XSSFCell cell = row.createCell(j); cell.setCellValue(content); } j++; } } if(poiModels != null && poiModels.size() != 0) { for(Integer key : poiModels.keySet()) { PoiModel poiModel = poiModels.get(key); XSSFRow lastRow = sheet1.getRow(poiModel.getRowIndex()); XSSFCell lastCell = lastRow.getCell(poiModel.getCellIndex()); lastCell.setCellValue(poiModel.getContent()); lastCell.setCellStyle(style); lastRow.setRowStyle(style); if(poiModel.getRowIndex() != i + dataSatrtIndex -1) { sheet1.addMergedRegion(new CellRangeAddress(poiModel.getRowIndex(), i + dataSatrtIndex - 1, poiModel.getCellIndex(), poiModel.getCellIndex())); } } } } else { flag = -1; }

可以考虑新增以下功能：

1. 合并单元格：根据传入的合并行数，将指定列的单元格进行合并。可以使用XSSFCellStyle的setAlignment()方法，将内容对齐方式设置为居中。

示例代码：

// 获取合并列数
int mergeCount = Integer.parseInt(mergeIndex.get(2).toString());

// 合并单元格
for (int i = 0; i < mergeCount; i++) {
    String startCell = mergeIndex.get(0) + (Integer.parseInt(mergeIndex.get(1).toString()) + i);
    String endCell = mergeIndex.get(0) + (Integer.parseInt(mergeIndex.get(1).toString()) + mergeCount - 1);
    CellRangeAddress cellRange = new CellRangeAddress(CellReference.convertColStringToIndex(startCell.substring(0, 1)), Integer.parseInt(startCell.substring(1)) - 1,
                                                      CellReference.convertColStringToIndex(endCell.substring(0, 1)), Integer.parseInt(endCell.substring(1)) - 1);
    sheet1.addMergedRegion(cellRange);
    // 设置对齐方式
    XSSFCellStyle style = wb.createCellStyle();
    style.setAlignment(HorizontalAlignment.CENTER);
    cellRange.setCellStyle(style);
}

2. 设置表头样式：可以使用XSSFCellStyle的setFont()方法和setFillForegroundColor()方法，分别设置字体和背景颜色。

示例代码：

// 设置表头样式
XSSFCellStyle headerStyle = wb.createCellStyle();
headerStyle.setFillForegroundColor(IndexedColors.GREY_25_PERCENT.getIndex());
headerStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
XSSFFont font = wb.createFont();
font.setFontHeightInPoints((short) 12);
font.setBold(true);
headerStyle.setFont(font);
// 设置表头单元格样式
for (int i = 0; i < columns.size(); i++) {
    sheet1row1.getCell(i).setCellStyle(headerStyle);
}

3. 设置列宽：可以使用setColumnWidth()方法设置指定列的宽度。

示例代码：

// 设置列宽
for (int i = 0; i < columns.size(); i++) {
    sheet1.setColumnWidth(i, 5000);
}

完整代码如下：

public static int exportToExcelForXlsx(List<List> objData, String sheetName, List<String> columns, List mergeIndex, HttpServletResponse response) {
    int flag = 0;
    XSSFWorkbook wb = new XSSFWorkbook();
    XSSFSheet sheet1 = wb.createSheet(sheetName);
    // 创建表头
    XSSFRow sheet1row1 = sheet1.createRow(0);
    for (int i = 0; i < columns.size(); i++) {
        sheet1row1.createCell(i).setCellValue(columns.get(i));
    }
    // 设置表头样式
    XSSFCellStyle headerStyle = wb.createCellStyle();
    headerStyle.setFillForegroundColor(IndexedColors.GREY_25_PERCENT.getIndex());
    headerStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
    XSSFFont font = wb.createFont();
    font.setFontHeightInPoints((short) 12);
    font.setBold(true);
    headerStyle.setFont(font);
    // 设置表头单元格样式
    for (int i = 0; i < columns.size(); i++) {
        sheet1row1.getCell(i).setCellStyle(headerStyle);
    }
    // 填充数据
    for (int i = 0; i < objData.size(); i++) {
        XSSFRow row = sheet1.createRow(i + 1);
        for (int j = 0; j < objData.get(i).size(); j++) {
            row.createCell(j).setCellValue(objData.get(i).get(j).toString());
        }
    }
    // 设置列宽
    for (int i = 0; i < columns.size(); i++) {
        sheet1.setColumnWidth(i, 5000);
    }
    // 合并单元格
    int mergeCount = Integer.parseInt(mergeIndex.get(2).toString());
    for (int i = 0; i < mergeCount; i++) {
        String startCell = mergeIndex.get(0) + (Integer.parseInt(mergeIndex.get(1).toString()) + i);
        String endCell = mergeIndex.get(0) + (Integer.parseInt(mergeIndex.get(1).toString()) + mergeCount - 1);
        CellRangeAddress cellRange = new CellRangeAddress(CellReference.convertColStringToIndex(startCell.substring(0, 1)), Integer.parseInt(startCell.substring(1)) - 1,
                                                          CellReference.convertColStringToIndex(endCell.substring(0, 1)), Integer.parseInt(endCell.substring(1)) - 1);
        sheet1.addMergedRegion(cellRange);
        // 设置对齐方式
        XSSFCellStyle style = wb.createCellStyle();
        style.setAlignment(HorizontalAlignment.CENTER);
        cellRange.setCellStyle(style);
    }
    // 导出excel文件
    try {
        OutputStream out = response.getOutputStream();
        String fileName = sheetName + ".xlsx";
        response.setHeader("Content-disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
        response.setContentType("application/vnd.ms-excel;charset=utf-8");
        wb.write(out);
        out.flush();
        out.close();
    } catch (IOException e) {
        e.printStackTrace();
        flag = 1;
    }
    return flag;
}