帮我用java 写一个 多线程实现Excel 导出的案例

好的，以下是一个多线程实现Excel导出的简单案例：

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

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.xssf.usermodel.XSSFWorkbook;

public class ExcelExporter implements Runnable {
    private List<List<Object>> data;
    private String filename;

    public ExcelExporter(List<List<Object>> data, String filename) {
        this.data = data;
        this.filename = filename;
    }

    @Override
    public void run() {
        XSSFWorkbook workbook = new XSSFWorkbook();
        Sheet sheet = workbook.createSheet("Sheet1");

        int rowNum = 0;
        for (List<Object> rowData : data) {
            Row row = sheet.createRow(rowNum++);
            int colNum = 0;
            for (Object field : rowData) {
                Cell cell = row.createCell(colNum++);
                if (field instanceof String) {
                    cell.setCellValue((String) field);
                } else if (field instanceof Integer) {
                    cell.setCellValue((Integer) field);
                } else if (field instanceof Double) {
                    cell.setCellValue((Double) field);
                }
            }
        }

        try {
            FileOutputStream outputStream = new FileOutputStream(new File(filename));
            workbook.write(outputStream);
            workbook.close();
            outputStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        List<List<Object>> data1 = List.of(
            List.of("Alice", 25),
            List.of("Bob", 30),
            List.of("Charlie", 35)
        );
        List<List<Object>> data2 = List.of(
            List.of("David", 40),
            List.of("Emily", 45),
            List.of("Frank", 50)
        );
        List<List<Object>> data3 = List.of(
            List.of("Grace", 55),
            List.of("Henry", 60),
            List.of("Ivy", 65)
        );

        ExecutorService executorService = Executors.newFixedThreadPool(3);
        executorService.execute(new ExcelExporter(data1, "file1.xlsx"));
        executorService.execute(new ExcelExporter(data2, "file2.xlsx"));
        executorService.execute(new ExcelExporter(data3, "file3.xlsx"));
        executorService.shutdown();
    }
}

在这个案例中，我们定义了一个 ExcelExporter 类，该类实现了 Runnable 接口，即可实现多线程。在类的构造函数中接受数据和文件名参数，并在 run() 方法中使用 Apache POI 库将数据导出到 Excel 文件中。在主函数中，我们创建了三个 ExcelExporter 对象并使用 ExecutorService 管理线程池，最后等待所有线程完成工作。这个案例中导出的 Excel 文件可以分别命名为 file1.xlsx，file2.xlsx 和 file3.xlsx。