import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
import org.springframework.stereotype.Component;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.List;

@Component
public class ExcelMergeUtility {

    /**
     * 合并Excel中內(nèi)容相同的單元格
     *
     * @param workbook       工作簿
     * @param sheetName      工作表名稱
     * @param columnsToMerge 需要合并的列索引列表
     * @param isRowMerge     是否按行合并（縱向合并）
     * @param isColumnMerge  是否按列合并（橫向合并）
     */
    public void mergeCells(Workbook workbook, String sheetName, List<Integer> columnsToMerge,
                           boolean isRowMerge, boolean isColumnMerge) {
        Sheet sheet = workbook.getSheet(sheetName);
        if (sheet == null) {
            throw new IllegalArgumentException("工作表 " + sheetName + " 不存在");
        }

        // 記錄第一列的合并行數(shù)
        int firstColMergeEndRow = 0;

        for (int colIndex : columnsToMerge) {
            for (int rowIndex = 0; rowIndex <= sheet.getLastRowNum(); rowIndex++) {
                Row currentRow = sheet.getRow(rowIndex);
                if (currentRow == null) continue;

                Cell currentCell = currentRow.getCell(colIndex);
                if (currentCell == null) continue;

                String currentValue = currentCell.getStringCellValue();

                if (isRowMerge) {
                    // 縱向合并
                    int mergeStartRow = rowIndex;
                    while (rowIndex + 1 <= sheet.getLastRowNum()) {
                        Row nextRow = sheet.getRow(rowIndex + 1);
                        if (nextRow == null) break;

                        Cell nextCell = nextRow.getCell(colIndex);
                        if (nextCell == null || !nextCell.getStringCellValue().equals(currentValue)) break;

                        // 如果當(dāng)前列不是第一列，且合并行數(shù)超過(guò)前一列的合并行數(shù)，則停止合并
                        if (colIndex > 0 && rowIndex + 1 > getMergeEndRow(sheet, mergeStartRow, colIndex - 1)) break;

                        // 如果合并行數(shù)超過(guò)第一列的合并行數(shù)，則停止合并
                        if (colIndex > 0 && rowIndex + 1 > firstColMergeEndRow) break;

                        rowIndex++;
                    }
                    if (mergeStartRow != rowIndex) {
                        sheet.addMergedRegion(new CellRangeAddress(mergeStartRow, rowIndex, colIndex, colIndex));
                    }

                    // 如果是第一列，記錄合并的最后一行
                    if (colIndex == 0) {
                        firstColMergeEndRow = rowIndex;
                    }
                }

                if (isColumnMerge) {
                    // 橫向合并
                    int mergeStartCol = colIndex;
                    while (colIndex + 1 < currentRow.getLastCellNum()) {
                        Cell nextCell = currentRow.getCell(colIndex + 1);
                        if (nextCell == null || !nextCell.getStringCellValue().equals(currentValue)) break;

                        colIndex++;
                    }
                    if (mergeStartCol != colIndex) {
                        sheet.addMergedRegion(new CellRangeAddress(rowIndex, rowIndex, mergeStartCol, colIndex));
                    }
                }
            }
        }
    }

    /**
     * 獲取指定單元格的合并的最后一行
     *
     * @param sheet     工作表
     * @param rowIndex  行索引
     * @param colIndex  列索引
     * @return 合并的最后一行
     */
      private int getMergeEndRow(Sheet sheet, int rowIndex, int colIndex) {
        int numMergedRegions = sheet.getNumMergedRegions();
        for (int i = 0; i < numMergedRegions; i++) {
            CellRangeAddress mergedRegion = sheet.getMergedRegion(i);
            if (mergedRegion.isInRange(rowIndex, colIndex)) {
                return mergedRegion.getLastRow();
            }
        }
//        for (CellRangeAddress mergedRegion : sheet.getMergedRegions()) {
//            if (mergedRegion.isInRange(rowIndex, colIndex)) {
//                return mergedRegion.getLastRow();
//            }
//        }
        return rowIndex; // 如果沒(méi)有合并，則返回當(dāng)前行
    }

    /**
     * 示例：生成Excel并合并單元格
     */
    public void generateAndMergeExcel(String filePath, String sheetName, List<Integer> columnsToMerge,
                                      boolean isRowMerge, boolean isColumnMerge) throws IOException {
        // 打開現(xiàn)有的Excel文件
        Workbook workbook = WorkbookFactory.create(new FileInputStream(filePath));

        // 合并單元格
        mergeCells(workbook, sheetName, columnsToMerge, isRowMerge, isColumnMerge);

        // 寫入文件
        try (FileOutputStream fileOut = new FileOutputStream(filePath)) {
            workbook.write(fileOut);
        }

        workbook.close();
    }
}

List<Integer> columnsToMerge = Arrays.asList(0, 1, 2, 3, 4, 5); // 合并第1列和第2列
boolean isRowMerge = true; // 啟用縱向合并
boolean isColumnMerge = false; // 禁用橫向合并

excelMergeUtility.generateAndMergeExcel("C:\\Users\\xxxx\\Downloads\\匯總記錄2025-03-04%2B10_38_30.xls", "匯總", columnsToMerge, isRowMerge, isColumnMerge);

<!-- Apache POI 核心庫(kù) -->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>4.1.2</version>
</dependency>
<!-- Apache POI OOXML 庫(kù)，用于處理 .xlsx 文件 -->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>4.1.2</version>
</dependency>