Apache POI提供了并行处理的支持，可以在处理大型Excel文件时提高效率。下面是一个示例代码，演示如何在Apache POI中并行读取Excel文件：

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;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import java.io.FileInputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.*;

public class ExcelReader {

    public static void main(String[] args) {
        String fileName = "example.xlsx";

        try (FileInputStream inputStream = new FileInputStream(fileName);
             Workbook workbook = new XSSFWorkbook(inputStream)) {

            Sheet sheet = workbook.getSheetAt(0);
            int numThreads = Runtime.getRuntime().availableProcessors();
            ExecutorService executorService = Executors.newFixedThreadPool(numThreads);

            List>> futures = new ArrayList<>();

            for (int i = 0; i < sheet.getLastRowNum(); i++) {
                final Row row = sheet.getRow(i);

                Callable> callable = () -> {
                    List values = new ArrayList<>();

                    for (int j = 0; j < row.getLastCellNum(); j++) {
                        Cell cell = row.getCell(j);
                        values.add(cell.getStringCellValue());
                    }

                    return values;
                };

                Future> future = executorService.submit(callable);
                futures.add(future);
            }

            List> results = new ArrayList<>();
            for (Future> future : futures) {
                List result = future.get();
                results.add(result);
            }

            for (List result : results) {
                System.out.println(result);
            }

            executorService.shutdown();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

在上面的代码中，我们使用ExecutorService和Callable来并行读取Excel文件中的每一行。为了让程序在多核CPU上运行效率更高，我们将线程池大小设置为当前系统可用的CPU核心数。

我们在for循环中创建一个Callable，