java生成Excel下拉框

public XSSFWorkbook exportExcel()throws Exception{
        XSSFWorkbook workbook = new XSSFWorkbook();
        XSSFSheet sheet = workbook.createSheet("下拉列表");
        String[] rank = new String[]{"高","中","低"};
        XSSFDataValidationHelper validationHelper = (XSSFDataValidationHelper) sheet.getDataValidationHelper();
        XSSFDataValidationConstraint  daConstraint = (XSSFDataValidationConstraint) validationHelper.createExplicitListConstraint(rank);
        CellRangeAddressList addressList = null;
        XSSFDataValidation validation = null;
        for(int i = 0;i < 100;i++){
            addressList = new CellRangeAddressList(i, i, 0, 0);
            validation = (XSSFDataValidation) validationHelper.createValidation(
                    daConstraint, addressList); 
            validation.setSuppressDropDownArrow(true);
            validation.setShowErrorBox(true); 
            sheet.addValidationData(validation);
        }
        return workbook;
    }