POI学习（一）数据校验之创建下拉列表框

POI创建Excel下拉列表框来设置表格数据有效性，这里需要使用几个重要的对象，关系依赖图如下

1. XSSFDataValidationHelper 工具类
2. XSSFDataValidationConstraint 设置数据有效性条件
3. CellRangeAddressList 设定有效区域
4. XSSFDataValidation 数据有效性对象，工具类1通过2和3来创建

具体代码可以参考如下

// 创建工作薄
XSSFWorkbook workbook = new XSSFWorkbook();
XSSFSheet sheet = workbook.createSheet("下拉列表框");
XSSFDataValidationHelper dvHelper = new XSSFDataValidationHelper(sheet);
XSSFDataValidationConstraint dvConstraint = (XSSFDataValidationConstraint) dvHelper
		.createExplicitListConstraint(new String[] {
    "男", "女" });
// 设置区域边界
CellRangeAddressList addressList = new CellRangeAddressList(0, 10, 0, 0);
XSSFDataValidation validation = (XSSFDataValidation) dvHelper
		.createValidation(dvConstraint, addressList);
// 输入非法数据时，弹窗警告框
validation.setShowErrorBox(true);
// 设置提示框
validation.createPromptBox("温馨提示", "请选择性别！！!");
validation.setShowPromptBox(true);
sheet.addValidationData(validation);
FileOutputStream out = new FileOutputStream(filePath);
workbook.write(out);
out.close();