code: protected HSSFCellStyle getTitleStyle() {
      HSSFCellStyle style = workbook.createCellStyle();
      style.setAlignment(HorizontalAlignment.CENTER);// 左右居中
      style.setVerticalAlignment(VerticalAlignment.CENTER);// 上下居中
      style.setFillPattern(FillPatternType.SOLID_FOREGROUND);
      style.setFillForegroundColor(HSSFColorPredefined.GREY_25_PERCENT.getIndex());
      return style;
    }
docs: <p>
  getTitleStyle.
  </p>
  
  @return a {@link org.apache.poi.hssf.usermodel.HSSFCellStyle} object.