java - 将两个 Excel 工作表合并到一个 Excel 工作簿中，而不将它们加载到内存中

Question

各位，

我们有一个要求，希望使用 JAVA 将两个 Excel 工作表合并到一个工作簿中。

我们知道这可以通过 Apache POI 来完成。

但我们不想做以下事情。我们只想将这两个 Excel 文件合并到单个工作簿中。

不要做:将两个 Excel 文件加载到内存中。它们的内容非常庞大，超过 10 万行。

谢谢。

Answer 1

您不能只是将工作表复制到另一个工作簿。您需要创建一个新工作簿，然后创建一个工作表并逐个单元格添加工作表的内容。

我可以帮助您使用两种复制行、复制单元格和依赖方法的方法:

/**
 * Copy row with style and merged region. This manage a shift in copy. You can copy row 1 to 10 and paste it between. this method can be use for copying in same sheet
 * 21 and 30
 * @param pSrcSheet source sheet
 * @param pDestSheet dest sheet
 * @param pSrcLine line to copy
 * @param pDestLine line to paste
 * @param pStyleMap just get a new HashMap<Integer, CellStyle> pStyleMap
 * @param pLineShift the shift set 0 if you don't need to shift your row. Example copy row 1 to 10 and paste it between 21 and 30 you
 *            need set thhe shift value 20. The value could be negative to pick up the data
 */
public static void copyRow(Sheet pSrcSheet, Sheet pDestSheet, Row pSrcLine, Row pDestLine,
    Map<Integer, CellStyle> pStyleMap, int pLineShift)
{
    ArrayList<CellRangeAddress> mergedRegions = getMergedRegions(pDestSheet);
    pDestLine.setHeight(pSrcLine.getHeight());
    for (int j = pSrcLine.getFirstCellNum(); j < pSrcLine.getLastCellNum(); j++)
    {
        Cell oldCell = null;
        Cell newCell = null;
        // if no cell in row skip the iteration
        if (j >= 0)
        {
            oldCell = pSrcLine.getCell(j);
            newCell = pDestLine.getCell(j, Row.CREATE_NULL_AS_BLANK);
        }

        if (oldCell != null)
        {
            if (newCell == null)
            {
                newCell = pDestLine.createCell(j);
            }
            copyCell(oldCell, newCell, pStyleMap);
            CellRangeAddress mergedRegion =
                getCurrentMergedRegion(pSrcSheet, pSrcLine.getRowNum(), (short) oldCell.getColumnIndex());
            if (mergedRegion != null)
            {
                CellRangeAddress newMergedRegion =
                    new CellRangeAddress(mergedRegion.getFirstRow() + pLineShift, mergedRegion.getLastRow()
                        + pLineShift, mergedRegion.getFirstColumn(), mergedRegion.getLastColumn());
                if (isNewMergedRegion(newMergedRegion, mergedRegions))
                {
                    mergedRegions.add(newMergedRegion);
                    pDestSheet.addMergedRegion(newMergedRegion);
                }
            }
        }
    }

}

/**
 * Copy cell with style from same workbook or not
 * @param pOldCell
 * @param pNewCell
 * @param pStyleMap
 */
public static void copyCell(Cell pOldCell, Cell pNewCell, Map<Integer, CellStyle> pStyleMap)
{
    if (pStyleMap != null)
    {
        if (pOldCell.getSheet().getWorkbook() == pNewCell.getSheet().getWorkbook())
        {
            pNewCell.setCellStyle(pOldCell.getCellStyle());
        }
        else
        {
            int stHashCode = pOldCell.getCellStyle().hashCode();
            CellStyle newCellStyle = pStyleMap.get(stHashCode);
            if (newCellStyle == null)
            {
                newCellStyle = pNewCell.getSheet().getWorkbook().createCellStyle();
                newCellStyle.cloneStyleFrom(pOldCell.getCellStyle());
                pStyleMap.put(stHashCode, newCellStyle);
            }
            pNewCell.setCellStyle(newCellStyle);
        }
    }
    switch (pOldCell.getCellType())
    {
        case Cell.CELL_TYPE_STRING:
            pNewCell.setCellValue(pOldCell.getStringCellValue());
            break;
        case Cell.CELL_TYPE_NUMERIC:
            pNewCell.setCellValue(pOldCell.getNumericCellValue());
            break;
        case Cell.CELL_TYPE_BLANK:
            pNewCell.setCellType(Cell.CELL_TYPE_BLANK);
            break;
        case Cell.CELL_TYPE_BOOLEAN:
            pNewCell.setCellValue(pOldCell.getBooleanCellValue());
            break;
        case Cell.CELL_TYPE_ERROR:
            pNewCell.setCellErrorValue(pOldCell.getErrorCellValue());
            break;
        case Cell.CELL_TYPE_FORMULA:
            pNewCell.setCellFormula(pOldCell.getCellFormula());
            break;
        default:
            break;
    }

}

/**
 * return the cellRangeAdress of the merge region where the cell is. Null if the cell is not in merged region
 * @param pSheet
 * @param pRowNum
 * @param pCellNum
 * @return return the cellRangeAdress of the merge region where the cell is. Null if the cell is not in merged
 *         region
 */
public static CellRangeAddress getCurrentMergedRegion(Sheet pSheet, int pRowNum, int pCellNum)
{
    for (int i = 0; i < pSheet.getNumMergedRegions(); i++)
    {
        CellRangeAddress merged = pSheet.getMergedRegion(i);
        if (merged.isInRange(pRowNum, pCellNum))
        {
            return merged;
        }
    }
    return null;
}

/**
 * return the index of the merge region where the cell is. -1 if the cell is not in merged region
 * @param pSheet
 * @param pRowNum
 * @param pCellNum
 * @return return the index of the merge region where the cell is. -1 if the cell is not in merged region
 */
public static int getCurrentMergedRegionIndex(Sheet pSheet, int pRowNum, int pCellNum)
{
    for (int i = 0; i < pSheet.getNumMergedRegions(); i++)
    {
        CellRangeAddress merged = pSheet.getMergedRegion(i);
        if (merged.isInRange(pRowNum, pCellNum))
        {
            return i;
        }
    }
    return -1;
}

/**
 * return the cellRangeAdress of the merge region where the cell is. Null if the cell is not in merged region
 * @param pSheet
 * @param pRowNum
 * @param pCellNum
 * @return return the cellRangeAdress of the merge region where the cell is. Null if the cell is not in merged
 *         region
 */
public static ArrayList<CellRangeAddress> getMergedRegions(Sheet pSheet)
{
    ArrayList<CellRangeAddress> mergedRegions = new ArrayList<CellRangeAddress>();
    for (int i = 0; i < pSheet.getNumMergedRegions(); i++)
    {
        mergedRegions.add(pSheet.getMergedRegion(i));
    }
    return mergedRegions;
}

/**
 * verify all boolean are true
 * @param pValues
 * @return
 */
public static boolean areAllTrue(boolean... pValues)
{
    for (int i = 0; i < pValues.length; ++i)
    {
        if (pValues[i] != true)
        {
            return false;
        }
    }
    return true;
}

/**
 * Compare 2 region if they are the same return true
 * @param pRegion region compare to pRegion2
 * @param pRegion2 region compare to pRegion
 * @return true if the region are the same, false if region are different
 */
public static boolean cellRangeAdressEquals(CellRangeAddress pRegion, CellRangeAddress pRegion2)
{
    boolean r1 = (pRegion.getFirstRow() == pRegion2.getFirstRow());
    boolean r2 = (pRegion.getLastRow() == pRegion2.getLastRow());
    boolean c1 = (pRegion.getFirstColumn() == pRegion2.getFirstColumn());
    boolean c2 = (pRegion.getLastColumn() == pRegion2.getLastColumn());
    return areAllTrue(r1, r2, c1, c2);
}

/**
 * Verify the it's a new region or existing
 * @param pNewMergedRegion
 * @param pMergedRegions
 * @return
 */
public static boolean isNewMergedRegion(CellRangeAddress pNewMergedRegion,
    ArrayList<CellRangeAddress> pMergedRegions)
{

    boolean isNew = true;
    int i = 0;
    // we want to check if newMergedRegion is contained inside our collection
    while (pMergedRegions != null && i < pMergedRegions.size() && isNew)
    {
        if (cellRangeAdressEquals(pMergedRegions.get(i), pNewMergedRegion))
        {
            isNew = false;
        }
        i++;
    }

    return isNew;
}

您可以在此线程上找到一些帮助:http://www.coderanch.com/t/420958/open-source/Copying-sheet-excel-file-excel

如果您有有关问题的更多信息，我会尽力帮助您;)