poi导出excel-下拉列表值超过255问题

public void exportExcel(List<List<String>> list,HttpServletResponse response,String fileName) throws Exception {

    XSSFWorkbook wb = new XSSFWorkbook();    XSSFSheet sheetCs = wb.createSheet("sheet1");    //为首行赋值    for(int i=0;i<list.size();i++){        XSSFRow row = sheetCs.createRow(i);        for(int j=0;j<list.get(i).size();j++){            sheetCs.setColumnWidth(j, 3500);//设置列宽            XSSFCell cell = row.createCell(j);            cell.setCellValue(list.get(i).get(j));        }    }    int sheetTotal=wb.getNumberOfSheets();    XSSFRow row;    //第一个下拉选    //新建一个sheet页    String hiddenSheetName = "hiddenSheet" + sheetTotal;    XSSFSheet hiddenSheet = wb.createSheet(hiddenSheetName);    //数据    String[] selectList =new String[100]; //对应列下拉框数据    for(int i=0;i<100;i++){        selectList[i]="测试数据"+i;    }    //写入下拉数据到新的sheet页中    for (int i = 0; i < selectList.length; i++) {        row = hiddenSheet.createRow(i);        XSSFCell cell = row.createCell(0);        cell.setCellValue(selectList[i]);    }    //获取新sheet页内容    String strFormula = hiddenSheetName + "!$A$1:$A$65535";    XSSFDataValidationConstraint constraint = new XSSFDataValidationConstraint(DataValidationConstraint.ValidationType.LIST,strFormula);    // 设置数据有效性加载在哪个单元格上,四个参数分别是：起始行、终止行、起始列、终止列    CellRangeAddressList regions = new CellRangeAddressList(1,65535, 0, 0);    // 数据有效性对象    DataValidationHelper help = new XSSFDataValidationHelper((XSSFSheet) sheetCs);    DataValidation validation = help.createValidation(constraint, regions);    sheetCs.addValidationData(validation);    //将新建的sheet页隐藏掉    wb.setSheetHidden(sheetTotal, true);    sheetTotal++;    //第二个下拉选    hiddenSheetName = "hiddenSheet" + sheetTotal;    XSSFSheet hiddenSheet2 = wb.createSheet(hiddenSheetName);    String[] selectList2 =new String[100]; //对应列下拉框数据    for(int i=0;i<100;i++){        selectList2[i]="测试数据2"+i;    }    for (int i = 0; i < selectList2.length; i++) {        row = hiddenSheet2.createRow(i);        XSSFCell cell = row.createCell(0);        cell.setCellValue(selectList2[i]);    }    String strFormula2 = hiddenSheetName + "!$A$1:$A$65535";    XSSFDataValidationConstraint constraint2 = new XSSFDataValidationConstraint(DataValidationConstraint.ValidationType.LIST,strFormula2);    CellRangeAddressList regions2 = new CellRangeAddressList(1,65535, 1, 1);    DataValidationHelper help2 = new XSSFDataValidationHelper((XSSFSheet) sheetCs);    DataValidation validation2 = help2.createValidation(constraint2, regions2);    sheetCs.addValidationData(validation2);    wb.setSheetHidden(sheetTotal, true);    sheetTotal++;    try {        OutputStream output = response.getOutputStream();        fileName = URLEncoder.encode(fileName,"UTF-8");        response.addHeader("Content-Disposition", "inline;filename="+fileName+".xls");        response.setContentType("application/msexcel");        wb.write(output);        output.flush();        output.close();    } catch (Exception e) {        // TODO Auto-generated catch block        e.printStackTrace();    }    // 结束    System.out.println("Over");

}