POI合并单元格出现边框不完整的问题

/**
 * @Description: 创建日期行(需合并单元格)
*/
protected void createTableDateRow(ExcelExportData setInfo, HSSFSheet[] sheets, int sheetNum, String operator) {
    // 合并单元格
    CellRangeAddress dateRange = new CellRangeAddress(1, 1, 0, setInfo.getGoodsFieldNames().get(sheetNum).length);
    sheets[sheetNum].addMergedRegion(dateRange);
    HSSFRow dateRow = sheets[sheetNum].createRow(1);
    for(int i = 0; i <= setInfo.getGoodsFieldNames().get(sheetNum).length ; i++){
       HSSFCell dateCell = dateRow.createCell(i);
       dateCell.setCellStyle(dateStyle);
    }
    dateRow.setHeight((short) 350);
    HSSFCell dateCell = dateRow.createCell(0);
    dateCell.setCellStyle(dateStyle);
    dateCell.setCellValue("下载时间:" + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date())+" 工作人员："+operator);
}