写一个java自定义线程池分批导出excel代码

好的，我可以为您提供java自定义线程池分批导出excel的代码，以下是示例代码：

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.Font;
import org.apache.poi.ss.usermodel.IndexedColors;
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.XSSFCellStyle;
import org.apache.poi.xssf.usermodel.XSSFFont;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class ExcelExporter {
  private static final int THREAD_COUNT = 4;
  private static final int BATCH_SIZE = 2000;
  private static ExecutorService threadPool =
      Executors.newFixedThreadPool(THREAD_COUNT);

  public void exportDataToExcel() throws Exception {
    Workbook workbook = new XSSFWorkbook();
    Sheet sheet = workbook.createSheet("Data");

    // Set header row style
    Font headerFont = workbook.createFont();
    headerFont.setBold(true);
    headerFont.setColor(IndexedColors.WHITE.getIndex());

    CellStyle headerCellStyle = workbook.createCellStyle();
    headerCellStyle.setFont(headerFont);
    headerCellStyle.setFillForegroundColor(IndexedColors.BLUE.getIndex());
    headerCellStyle.setFillPattern(XSSFCellStyle.SOLID_FOREGROUND);

    Row headerRow = sheet.createRow(0);
    headerRow.createCell(0).setCellValue("Column 1");
    headerRow.createCell(1).setCellValue("Column 2");
    headerRow.createCell(2).setCellValue("Column 3");

    for (int i = 0; i < 3; i++) {
      headerRow.getCell(i).setCellStyle(headerCellStyle);
    }

    // Start exporting data
    for (int i = 0; i < getTotalRowCount(); i += BATCH_SIZE) {
      int startRow = i + 1;
      int endRow = Math.min(i + BATCH_SIZE, getTotalRowCount()) + 1;

      threadPool.execute(
          new ExportTask(
              workbook,
              sheet,
              startRow,
              endRow));
    }

    threadPool.shutdown();
    threadPool.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS);
  }

  private static int getTotalRowCount() {
    // Return the total number of rows to export
    return 10000;
  }

  private static class ExportTask implements Runnable {
    private final Workbook workbook;
    private final Sheet sheet;
    private final int startRow;
    private final int endRow;

    ExportTask(
        Workbook workbook,
        Sheet sheet,
        int startRow,
        int endRow) {
      this.workbook = workbook;
      this.sheet = sheet;
      this.startRow = startRow;
      this.endRow = endRow;
    }

    @Override
    public void run() {
      try {
        // Simulate data retrieval
        Thread.sleep(100);

        // Export data to sheet
        for (int i = startRow; i < endRow; i++) {
          Row row = sheet.createRow(i);
          row.createCell(0).setCellValue("Value " + i);
          row.createCell(1).setCellValue("Value " + i * 2);
          row.createCell(2).setCellValue("Value " + i * 3);
        }
      } catch (Exception ex) {
        ex.printStackTrace();
      }
    }
  }
}

该代码中，我们使用了线程池来提高导出数据到excel时的效率。我们先设置一个每批次导出的行数，然后根据总行数和批次大小分批导出，每批次启动一个线程来处理。最后，等待所有线程完成后关闭线程池，导出工作完成。