EXCEL读取、拷贝、合并的简单工具类

package com.utils;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.xssf.usermodel.*;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.*;

public class ExcelUtil
{

    /**
     * 合并excel
     *
     * @param outputFileName
     * @param inputFileNameArray
     */
    public static void mergeExcel(String outputFileName, String... inputFileNameArray)
    {
        if (inputFileNameArray.length == 1)
        {
            System.out.println("至少需要两个文件才能合并，请验证！！！");
            return;
        }
        try
        {
            XSSFWorkbook newExcelCreate = new XSSFWorkbook();
            int a = 0;
            for (String f : inputFileNameArray)
            {
                InputStream in = new FileInputStream(f);
                XSSFWorkbook fromExcel = new XSSFWorkbook(in);
                for (int i = 0; i < fromExcel.getNumberOfSheets(); i++)
                {
                    //遍历每个sheet
                    a++;
                    XSSFSheet oldSheet = fromExcel.getSheetAt(i);
                    XSSFSheet newSheet = newExcelCreate.createSheet(a + "");
                    copySheet(newExcelCreate, oldSheet, newSheet);
                }
            }
            FileOutputStream fileOut = new FileOutputStream(outputFileName);
            newExcelCreate.write(fileOut);
            fileOut.flush();
            fileOut.close();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

    /**
     * 合并excel的sheet
     *
     * @param outputFileName
     * @param inputFileNameArray
     */
    public static void mergeExcelForOneSheet(String outputFileName, String... inputFileNameArray)
    {
        if (inputFileNameArray.length == 1)
        {
            System.out.println("至少需要两个文件才能合并，请验证！！！");
            return;
        }
        try
        {
            XSSFWorkbook newExcelCreate = new XSSFWorkbook();
            XSSFSheet newSheet = newExcelCreate.createSheet("文字识别结果,仅供参考 ! 查询完成请务必与图片结果核对");
            int rowNum = 0;
            for (String f : inputFileNameArray)
            {
                InputStream in = new FileInputStream(f);
                XSSFWorkbook fromExcel = new XSSFWorkbook(in);
                for (int i = 0; i < fromExcel.getNumberOfSheets(); i++)
                {
                    //遍历每个sheet
                    XSSFSheet oldSheet = fromExcel.getSheetAt(i);
                    for (int j = 0; j <= oldSheet.getLastRowNum(); j++)
                    {
                        rowNum++;
                        XSSFRow toRow = newSheet.createRow(rowNum);
                        copyRow(newExcelCreate, oldSheet.getRow(j), toRow);
                    }
                }
            }
            FileOutputStream fileOut = new FileOutputStream(outputFileName);
            newExcelCreate.write(fileOut);
            fileOut.flush();
            fileOut.close();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

    /**
     * 读取excel
     *
     * @param filePath
     * @return
     */
    public static Workbook readExcel(String filePath)
    {
        if (null == filePath)
        {
            return null;
        }
        String extString = filePath.substring(filePath.lastIndexOf("."));

        try
        {
            InputStream is = new FileInputStream(filePath);
            if (".xls".equals(extString))
            {
                return new HSSFWorkbook(is);
            }
            else if (".xlsx".equals(extString))
            {
                return new XSSFWorkbook(is);
            }
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 读取Cell
     *
     * @param cell
     * @return
     */
    public static Object getCellFormatValue(Cell cell)
    {
        Object cellValue = null;
        if (cell != null)
        {
            //判断cell类型
            switch (cell.getCellType())
            {
                case Cell.CELL_TYPE_NUMERIC:
                {
                    cellValue = String.valueOf(cell.getNumericCellValue());
                    break;
                }
                case Cell.CELL_TYPE_FORMULA:
                {
                    //判断cell是否为日期格式
                    if (DateUtil.isCellDateFormatted(cell))
                    {
                        //转换为日期格式YYYY-mm-dd
                        cellValue = cell.getDateCellValue();
                    }
                    else
                    {
                        //数字
                        cellValue = String.valueOf(cell.getNumericCellValue());
                    }
                    break;
                }
                case Cell.CELL_TYPE_STRING:
                {
                    cellValue = cell.getRichStringCellValue().getString();
                    break;
                }
                default:
                    cellValue = "";
            }
        }
        else
        {
            cellValue = "";
        }
        return cellValue;
    }

    /**
     * 合并单元格
     *
     * @param fromSheet
     * @param toSheet
     */
    public static void mergeSheetAllRegion(XSSFSheet fromSheet, XSSFSheet toSheet)
    {
        int num = fromSheet.getNumMergedRegions();
        CellRangeAddress cellR = null;
        for (int i = 0; i < num; i++)
        {
            cellR = fromSheet.getMergedRegion(i);
            toSheet.addMergedRegion(cellR);
        }
    }

    /**
     * 复制cell
     *
     * @param wb
     * @param fromCell
     * @param toCell
     */
    public static void copyCell(XSSFWorkbook wb, XSSFCell fromCell, XSSFCell toCell)
    {
        XSSFCellStyle newStyle = wb.createCellStyle();
        copyCellStyle(fromCell.getCellStyle(), newStyle);
        //样式
        toCell.setCellStyle(newStyle);
        if (fromCell.getCellComment() != null)
        {
            toCell.setCellComment(fromCell.getCellComment());
        }
        // 不同数据类型处理
        int fromCellType = fromCell.getCellType();
        toCell.setCellType(fromCellType);
        if (fromCellType == XSSFCell.CELL_TYPE_NUMERIC)
        {
            if (DateUtil.isCellDateFormatted(fromCell))
            {
                toCell.setCellValue(fromCell.getDateCellValue());
            }
            else
            {
                toCell.setCellValue(fromCell.getNumericCellValue());
            }
        }
        else if (fromCellType == XSSFCell.CELL_TYPE_STRING)
        {
            toCell.setCellValue(fromCell.getRichStringCellValue());
        }
        else if (fromCellType == XSSFCell.CELL_TYPE_BOOLEAN)
        {
            toCell.setCellValue(fromCell.getBooleanCellValue());
        }
        else if (fromCellType == XSSFCell.CELL_TYPE_ERROR)
        {
            toCell.setCellErrorValue(fromCell.getErrorCellValue());
        }
        else if (fromCellType == XSSFCell.CELL_TYPE_FORMULA)
        {
            toCell.setCellFormula(fromCell.getCellFormula());
        }
        else if (fromCellType == XSSFCell.CELL_TYPE_BLANK)
        {

        }
        else
        {

        }

    }

    /**
     * 复制行
     *
     * @param wb
     * @param oldRow
     * @param toRow
     */
    public static void copyRow(XSSFWorkbook wb, XSSFRow oldRow, XSSFRow toRow)
    {
        toRow.setHeight(oldRow.getHeight());
        for (Iterator cellIt = oldRow.cellIterator(); cellIt.hasNext(); )
        {
            XSSFCell tmpCell = (XSSFCell) cellIt.next();
            XSSFCell newCell = toRow.createCell(tmpCell.getColumnIndex());
            copyCell(wb, tmpCell, newCell);
        }
    }

    /**
     * 复制Sheet
     *
     * @param wb
     * @param fromSheet
     * @param toSheet
     */
    public static void copySheet(XSSFWorkbook wb, XSSFSheet fromSheet, XSSFSheet toSheet)
    {
        mergeSheetAllRegion(fromSheet, toSheet);
        //设置列宽
        for (int i = 0; i <= fromSheet.getRow(fromSheet.getFirstRowNum()).getLastCellNum(); i++)
        {
            toSheet.setColumnWidth(i, fromSheet.getColumnWidth(i));
        }
        for (Iterator rowIt = fromSheet.rowIterator(); rowIt.hasNext(); )
        {
            XSSFRow oldRow = (XSSFRow) rowIt.next();
            XSSFRow newRow = toSheet.createRow(oldRow.getRowNum());
            copyRow(wb, oldRow, newRow);
        }
    }

    /**
     * 克隆cell style
     */
    public static void copyCellStyle(XSSFCellStyle fromStyle, XSSFCellStyle toStyle)
    {
        //此一行代码搞定
        toStyle.cloneStyleFrom(fromStyle);
    }

    /**
     * 读取excel转成map
     *
     * @param filePath
     * @param beginRow
     * @return
     */
    public static List<Map<String, String>> readExcelToMap(String filePath, int beginRow)
    {
        List<Map<String, String>> list = new ArrayList<>();

        // 读取文件信息
        Workbook wb = ExcelUtil.readExcel(filePath);
        if (wb != null)
        {
            // 获取sheet总数
            int sheetNum = wb.getNumberOfSheets();

            for (int i = 0; i < sheetNum; i++)
            {
                // 获取sheet
                Sheet sheet = wb.getSheetAt(i);
                // 获取最大行数
                int rowNum = sheet.getPhysicalNumberOfRows();
                // 读取cell的标题
                Row titleRow = sheet.getRow(beginRow - 1);
                if (null == titleRow)
                {
                    continue;
                }
                // 获取明细列数
                int colNum = titleRow.getPhysicalNumberOfCells();

                // 遍历明细
                for (int x = beginRow; x < rowNum; x++)
                {
                    // 行map
                    Map<String, String> map = new LinkedHashMap<>();
                    // 行信息
                    Row row = sheet.getRow(x);

                    if (row != null)
                    {
                        // 遍历行并获取到返回值
                        for (int j = 0; j < colNum; j++)
                        {
                            Cell titleCell = titleRow.getCell(j);
                            Cell cell = row.getCell(j);
                            String titleCellData = (String) ExcelUtil.getCellFormatValue(titleCell);
                            String cellData = (String) ExcelUtil.getCellFormatValue(cell);
                            map.put(titleCellData, cellData);
                        }
                    }
                    else
                    {
                        break;
                    }
                    list.add(map);
                }
            }
        }
        return list;
    }
}