用java分页写一个读写大文件excel分成若干份的工具类

好的，以下是一个用Java分页读写大文件Excel并分成若干份的工具类的示例代码：

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

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;

public class ExcelSplitter {
    private static final int DEFAULT_PAGE_SIZE = 10000;

    public static void split(File inputFile, int pageSize) throws IOException {
        FileInputStream fis = new FileInputStream(inputFile);
        Workbook workbook = new HSSFWorkbook(fis);
        Sheet sheet = workbook.getSheetAt(0);
        int rowCount = sheet.getLastRowNum() + 1;
        int pageCount = (rowCount + pageSize - 1) / pageSize;
        List<Workbook> workbooks = new ArrayList<>();
        for (int i = 0; i < pageCount; i++) {
            Workbook newWorkbook = new HSSFWorkbook();
            Sheet newSheet = newWorkbook.createSheet();
            workbooks.add(newWorkbook);
            int startRow = i * pageSize;
            int endRow = Math.min(startRow + pageSize, rowCount);
            for (int j = startRow; j < endRow; j++) {
                Row oldRow = sheet.getRow(j);
                Row newRow = newSheet.createRow(j - startRow);
                for (int k = 0; k < oldRow.getLastCellNum(); k++) {
                    Cell oldCell = oldRow.getCell(k);
                    Cell newCell = newRow.createCell(k);
                    newCell.setCellValue(oldCell.getStringCellValue());
                }
            }
        }
        fis.close();
        for (int i = 0; i < workbooks.size(); i++) {
            File outputFile = new File(inputFile.getParentFile(), inputFile.getName() + "." + (i + 1) + ".xls");
            FileOutputStream fos = new FileOutputStream(outputFile);
            workbooks.get(i).write(fos);
            fos.close();
        }
    }

    public static void split(File inputFile) throws IOException {
        split(inputFile, DEFAULT_PAGE_SIZE);
    }
}

使用示例：

ExcelSplitter.split(new File("input.xls"), 5000);

这将把名为"input.xls"的文件分成若干份，每份最多包含5000行数据，并保存为"input.xls.1.xls"、"input.xls.2.xls"等文件。如果不指定分页大小，则默认为10000行。