POI exporta una gran cantidad de soluciones desplegables

1. Procesar ideas

• Cuando el número de menús desplegables es pequeño, cree el menú desplegable directamente
• Cuando el número de menús desplegables excede un cierto número, habrá errores al crear menús desplegables directamente, lo que resultará en una visualización anormal. En este momento, puede crear una hoja oculta y agregar verificación de datos de celda para señalar los datos en la hoja oculta que acaba de crear.

2. Código fuente

import com.hz.model.CommonException;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.ss.util.CellRangeAddressList;
import org.apache.poi.xssf.usermodel.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.CollectionUtils;
import org.springframework.util.StringUtils;

import java.io.BufferedReader;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.util.*;

/**
 * excel导出工具
 *
 * @author pp_lan
 */
public class ExcelExportUtils {

    private static final Logger LOGGER = LoggerFactory.getLogger(ExcelExportUtils.class);

    public String outputFile;

    private List<String> headers;

    private List<List<String>> dataList;

    private Map<Integer, List<String>> dropdownMap;

    private ExcelExportUtils() {
        this.outputFile = null;
        this.headers = null;
        this.dataList = null;
        this.dropdownMap = new HashMap<>();
    }


    public static final ExcelExportUtils getInstance() {
        return new ExcelExportUtils();
    }

    public ExcelExportUtils buildOutput(String outputFile) {
        this.outputFile = outputFile;
        return this;
    }

    public ExcelExportUtils buildHeader(List<String> headers) {
        this.headers = headers;
        return this;
    }

    public ExcelExportUtils buildData(List<List<String>> dataList) {
        this.dataList = dataList;
        return this;
    }

    public ExcelExportUtils buildDropdown(int columnIndex, List<String> dropdownContent) {
        this.dropdownMap.put(columnIndex, dropdownContent);
        return this;
    }



    public void createExcel(String sheetName) {

        // 校验数据
        this.checkData();

        try (FileOutputStream out = new FileOutputStream(outputFile)) {
            XSSFWorkbook workbook = new XSSFWorkbook();
            XSSFSheet sheet = workbook.createSheet(sheetName);

            sheet.setDefaultColumnWidth(18);
            sheet.setDefaultRowHeightInPoints(20);

            XSSFCellStyle headerStyle = buildStyle(workbook, true);
            XSSFCellStyle dataStyle = buildStyle(workbook, false);

            int rowNumber = 0;
            XSSFRow headerRow = sheet.createRow(rowNumber++);
            headerRow.setHeightInPoints(23);
            for (int i = 0; i < headers.size(); i++) {
                XSSFCell cell = headerRow.createCell(i);
                cell.setCellValue(headers.get(i));
                cell.setCellStyle(headerStyle);
            }

            for (int i = 0; i < dataList.size(); i++) {
                XSSFRow dataRow = sheet.createRow(rowNumber++);
                dataRow.setHeightInPoints(20);
                List<String> rowData = dataList.get(i);

                for (int j = 0; j < rowData.size(); j++) {
                    XSSFCell cell = dataRow.createCell(j);
                    cell.setCellValue(rowData.get(j));
                    cell.setCellStyle(dataStyle);
                }

            }

            // 创建下拉
            for (Map.Entry<Integer, List<String>> entry : this.dropdownMap.entrySet()) {
                Integer columnIndex = entry.getKey();
                List<String> dropdownList = entry.getValue();
                addDropDown(workbook, sheetName, columnIndex, dropdownList, dataList.size());
            }

            workbook.write(out);
            out.flush();

        } catch (Exception e) {
            throw new CommonException("导出异常", e);
        }
    }

    /**
     * 合并单元格
     *
     * @param sheet
     * @param row
     * @param firstCol
     * @param lastCol
     */
    private void addMergeCell(XSSFSheet sheet, int row, int firstCol, int lastCol) {
        CellRangeAddress cellAddresses = new CellRangeAddress(row, row, firstCol, lastCol);
        sheet.addMergedRegion(cellAddresses);
    }

    /**
     * 校验数据
     */
    private void checkData() {
        if (!StringUtils.hasText(outputFile)) {
            throw new CommonException("输出文件未设置");
        }

        if (CollectionUtils.isEmpty(headers)) {
            throw new CommonException("表头未设置");
        }
        if (CollectionUtils.isEmpty(dataList)) {
            throw new CommonException("数据未设置");
        }

        int headerSize = headers.size();
        for (List<String> data : dataList) {
            if (data == null) {
                continue;
            }

            int arrange = data.size();
            if (headerSize != arrange) {
                throw new CommonException("数据校验失败, 列和表头数量不一致");
            }
        }
    }

    /**
     * 添加下拉
     *
     * @param workbook
     * @param sheetName
     * @param column
     * @param dropdownList
     */
    private void addDropDown(XSSFWorkbook workbook, String sheetName,  int column, List<String> dropdownList, int dataSize) {

        if (CollectionUtils.isEmpty(dropdownMap)) {
            return;
        }

        if (dropdownList.size() <= 100) {
            XSSFSheet sheet = workbook.getSheet(sheetName);

            for (Map.Entry<Integer, List<String>> entry : dropdownMap.entrySet()) {
                Integer columnIndex = entry.getKey();
                List<String> dropDownList = entry.getValue();
                String[] options = dropDownList.toArray(new String[]{});

                XSSFDataValidationHelper dvHelper = new XSSFDataValidationHelper(sheet);
                DataValidationConstraint dvConstraint = dvHelper.createExplicitListConstraint(options);
                CellRangeAddressList addressList = new CellRangeAddressList(1, dataSize, columnIndex, columnIndex);
                DataValidation validation = dvHelper.createValidation(dvConstraint, addressList);
                sheet.addValidationData(validation);
            }

        } else {
            // 下拉项太多会有bug，采用此方案可以解决
            int sheetTotal = workbook.getNumberOfSheets();
            String hiddenSheetName = "hiddenSheet" + sheetTotal;
            XSSFSheet sheet = workbook.createSheet(hiddenSheetName);

            for (int i = 0; i < dropdownList.size(); i++) {
                XSSFRow row = sheet.createRow(i);
                XSSFCell cell = row.createCell(0);
                cell.setCellValue(dropdownList.get(i));
            }

            int dropdownSize = dropdownList.size();
            // 使用单元格A的数据进行单元格校验
            String strFormula = new StringBuilder().append(hiddenSheetName).append("!$A$1:$A$").append(dropdownSize).toString();

            XSSFDataValidationConstraint constraint = new XSSFDataValidationConstraint(DataValidationConstraint.ValidationType.LIST, strFormula);
            CellRangeAddressList cell = new CellRangeAddressList(1, dataSize, column, column);
            XSSFDataValidationHelper help = new XSSFDataValidationHelper(sheet);
            DataValidation validation = help.createValidation(constraint, cell);

            XSSFSheet dataSheet = workbook.getSheet(sheetName);
            if (dataSheet != null) {
                dataSheet.addValidationData(validation);
            }
            workbook.setSheetHidden(sheetTotal, true);
        }
    }


    /**
     * 创建单元格样式
     *
     * @param workbook
     * @param isHeader
     * @return
     */
    private static XSSFCellStyle buildStyle(XSSFWorkbook workbook, boolean isHeader) {
        XSSFCellStyle cellStyle = workbook.createCellStyle();
        cellStyle.setAlignment(HorizontalAlignment.CENTER);
        cellStyle.setVerticalAlignment(VerticalAlignment.CENTER);

        // 字体
        XSSFFont font = workbook.createFont();
        font.setFontName("宋体");
        if (isHeader) {
            font.setFontHeightInPoints((short) 12);
            font.setBold(true);
        } else {
            font.setFontHeightInPoints((short) 10);
            font.setBold(false);
        }
        cellStyle.setFont(font);

        // 边框
        cellStyle.setBorderTop(BorderStyle.THIN);
        cellStyle.setBorderBottom(BorderStyle.THIN);
        cellStyle.setBorderLeft(BorderStyle.THIN);
        cellStyle.setBorderRight(BorderStyle.THIN);

        return cellStyle;
    }
}

3. Ejemplos de uso

public static void main(String[] args) {
        List<String> headers = new ArrayList<>(Arrays.asList("银行名称", "列B", "列C"));

        // 下拉数量相对较少
        List<List<String>> dataList = new ArrayList<>();
        dataList.add(new ArrayList<>(Arrays.asList("中国银行", "2111", "3111")));
        dataList.add(new ArrayList<>(Arrays.asList("招商银行", "b111", "c111")));
        List<String> dropdownList = new ArrayList<>();
        for (int i = 0; i < 80; i++) {
            dropdownList.add("选项" + i);
        }

        // 下拉数量大于100
        ArrayList<String> dropdownList2 = new ArrayList<>();
        for (int i = 0; i < 300; i++) {
            dropdownList2.add("新选项" + i);
        }

        // 下拉数量较少
        List<String> bankList = new ArrayList<>();
        try (BufferedReader br = new BufferedReader(new FileReader("/home/xk/workspace/gitee/javarecord/doc/bankScrapy.txt"));) {
            String bank;
            while ((bank = br.readLine()) != null) {
                bankList.add(bank);
            }

        } catch (Exception e) {
            LOGGER.error("读取银行数据失败", e);
        }


        ExcelExportUtils excelExportUtils = ExcelExportUtils.getInstance();
        excelExportUtils.buildOutput("/home/xk/workspace/gitee/javarecord/doc/导出示例new.xlsx")
                .buildHeader(headers)
                .buildData(dataList)
                .buildDropdown(0, bankList)
                .buildDropdown(1, dropdownList)
                .buildDropdown(2, dropdownList2);

        excelExportUtils.createExcel("数据");
    }

4. Exportar muestra