java excel设置下拉为树状数据

你可以使用Apache POI库来设置Excel下拉为树状数据。下面是一个示例代码：

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddressList;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class ExcelTreeDropdownExample {
    public static void main(String[] args) {
        try (Workbook workbook = new XSSFWorkbook()) {
            Sheet sheet = workbook.createSheet("Sheet1");

            // 创建下拉列表的数据源
            String[] items1 = {"Fruit", "Apple", "Banana", "Orange"};
            String[] items2 = {"Color", "Red", "Blue", "Green"};
            String[] items3 = {"Animal", "Dog", "Cat", "Bird"};

            // 创建树状下拉列表的数据源
            String[] treeItems = {"Category", "Fruit", "Color", "Animal"};

            // 创建第一列的下拉列表
            createDropdown(sheet, 0, 1, 10, items1);

            // 创建第二列的下拉列表，绑定第一列的选中项
            createDropdown(sheet, 1, 1, 10, items2);
            sheet.addValidationData(createIndirectDataValidation(sheet, 1, 1, 10, 0));

            // 创建第三列的下拉列表，绑定第二列的选中项
            createDropdown(sheet, 2, 1, 10, items3);
            sheet.addValidationData(createIndirectDataValidation(sheet, 2, 1, 10, 1));

            // 设置第一行为树状下拉列表的数据源
            sheet.addValidationData(createListDataValidation(sheet, 0, 0, 0, 3, treeItems));

            // 保存Excel文件
            workbook.write(new FileOutputStream("tree_dropdown.xlsx"));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static void createDropdown(Sheet sheet, int columnIndex, int firstRow, int lastRow, String[] items) {
        DataValidationHelper dvHelper = sheet.getDataValidationHelper();
        DataValidationConstraint dvConstraint = dvHelper.createExplicitListConstraint(items);
        CellRangeAddressList addressList = new CellRangeAddressList(firstRow, lastRow, columnIndex, columnIndex);
        DataValidation validation = dvHelper.createValidation(dvConstraint, addressList);
        validation.setShowErrorBox(true);
        sheet.addValidationData(validation);
    }

    private static DataValidation createIndirectDataValidation(Sheet sheet, int columnIndex, int firstRow, int lastRow, int refColumnIndex) {
        DataValidationHelper dvHelper = sheet.getDataValidationHelper();
        SheetNameFormatter sheetNameFormatter = dvHelper.createSheetNameFormatter("$B$2:$B$4");
        String formula = sheetNameFormatter.format(sheet.getSheetName(), columnIndex + 1, columnIndex + 1);
        DataValidationConstraint dvConstraint = dvHelper.createFormulaListConstraint(formula);
        CellRangeAddressList addressList = new CellRangeAddressList(firstRow, lastRow, columnIndex, columnIndex);
        DataValidation validation = dvHelper.createValidation(dvConstraint, addressList);
        validation.setShowErrorBox(true);
        return validation;
    }

    private static DataValidation createListDataValidation(Sheet sheet, int columnIndex, int firstRow, int lastRow, int refColumnIndex, String[] items) {
        DataValidationHelper dvHelper = sheet.getDataValidationHelper();
        DataValidationConstraint dvConstraint = dvHelper.createExplicitListConstraint(items);
        CellRangeAddressList addressList = new CellRangeAddressList(firstRow, lastRow, columnIndex, columnIndex);
        DataValidation validation = dvHelper.createValidation(dvConstraint, addressList);
        validation.setShowErrorBox(true);
        return validation;
    }
}

这个示例代码会生成一个包含树状下拉列表的Excel文件。你可以根据自己的需求修改下拉列表的数据源和范围。请确保你已经添加了Apache POI库的依赖。