HSSFWorkbook workbook = new HSSFWorkbook();

HSSFCellStyle style = workbook.createCellStyle();

style.setFillForegroundColor(HSSFColor.LIME.index);

style.setFillBackgroundColor(HSSFColor.GREEN.index);

style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND); // 要有这一句