方式一：

新增一个名为序号的列,设置导出格式为：isAddIndex

不要在ExportParams 中设置addIndex 为true 这个没啥用

List<ExcelExportEntity> colList = new ArrayList<ExcelExportEntity>();
//自动新增首列序号
ExcelExportEntity xh = new ExcelExportEntity("序号", "xh");
xh.setFormat("isAddIndex");
colList.add(xh);

方式二：

第一步：重新定义一个ExcelExportUtil(easypoi 中的ExcelExportUtil是被final 修饰的)

如下图所示: SubExcelExportService是我们继承easypoi 的ExcelExportService 并重写了insertDataToSheet()方法。

import java.io.OutputStream;
import java.net.URLEncoder;
import java.util.Collection;
import java.util.List;

import javax.servlet.http.HttpServletResponse;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import cn.afterturn.easypoi.excel.entity.ExportParams;
import cn.afterturn.easypoi.excel.entity.enmus.ExcelType;
import cn.afterturn.easypoi.excel.entity.params.ExcelExportEntity;

public class ExcelExportUtil {

    public static Workbook exportExcel(ExportParams entity, List<ExcelExportEntity> entityList, Collection<?> dataSet) {
        Workbook workbook =getWorkbook(entity.getType(),dataSet.size());;
        new SubExcelExportService().createSheetForMap(workbook, entity, entityList, dataSet);
        return workbook;
    }

    public static Workbook exportExcel(ExportParams entity, Class<?> pojoClass, Collection<?> dataSet) {
        Workbook workbook =getWorkbook(entity.getType(), dataSet.size());
        new SubExcelExportService().createSheet(workbook, entity, pojoClass, dataSet);
        return workbook;
    }

    private static Workbook getWorkbook(ExcelType type, int size) {
        if (ExcelType.HSSF.equals(type)) {
            return new HSSFWorkbook();
        } else if (size < 100000) {
            return new XSSFWorkbook();
        } else {
            return new SXSSFWorkbook();
        }
    }

    public static void exportExcel(HttpServletResponse response, Workbook workbook) throws Exception {
        response.reset();
        response.setContentType("application/vnd.ms-excel");
        String fileName = System.currentTimeMillis() + ".xlsx";
        response.setHeader("Content-disposition", "attachment; filename=" + URLEncoder.encode(fileName, "UTF-8"));
        response.setCharacterEncoding("UTF-8");
        OutputStream output = response.getOutputStream();
        workbook.write(output);
        workbook.close();
        output.close();
    }
}

第二步：继承ExcelExportService 并重写insertDataToSheet()方法

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

import org.apache.poi.ss.usermodel.Drawing;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;

import cn.afterturn.easypoi.excel.entity.ExportParams;
import cn.afterturn.easypoi.excel.entity.params.ExcelExportEntity;
import cn.afterturn.easypoi.excel.export.ExcelExportService;
import cn.afterturn.easypoi.excel.export.styler.IExcelExportStyler;
import cn.afterturn.easypoi.exception.excel.ExcelExportException;
import cn.afterturn.easypoi.exception.excel.enums.ExcelExportEnum;
import cn.afterturn.easypoi.util.PoiExcelGraphDataUtil;

public class SubExcelExportService extends ExcelExportService {
    private static intMAX_NUM= 60000;

    @Override
    protected void insertDataToSheet(Workbook workbook, ExportParams entity, List<ExcelExportEntity> entityList,
                                     Collection<?> dataSet, Sheet sheet) {
        try {
            dataHandler = entity.getDataHandler();
            if (dataHandler != null && dataHandler.getNeedHandlerFields() != null) {
                needHandlerList = Arrays.asList(dataHandler.getNeedHandlerFields());
            }
            dictHandler = entity.getDictHandler();
            i18nHandler = entity.getI18nHandler();
            // 创建表格样式
            setExcelExportStyler(
                    (IExcelExportStyler) entity.getStyle().getConstructor(Workbook.class).newInstance(workbook));
            Drawing patriarch = PoiExcelGraphDataUtil.getDrawingPatriarch(sheet);
            List<ExcelExportEntity> excelParams = new ArrayList<ExcelExportEntity>();
            if (entity.isAddIndex()) {
                excelParams.add(indexExcelEntity(entity));
            }
            excelParams.addAll(entityList);
            int index = entity.isCreateHeadRows() ? createHeaderAndTitle(entity, sheet, workbook, excelParams) : 0;
            int titleHeight = index;
            setCellWith(excelParams, sheet);
            setColumnHidden(excelParams, sheet);
            short rowHeight = entity.getHeight() != 0 ? entity.getHeight() : getRowHeight(excelParams);
            setCurrentIndex(1);
            Iterator<?> its = dataSet.iterator();
            List<Object> tempList = new ArrayList<Object>();
            while (its.hasNext()) {
                Object t = its.next();
                index += createCells(patriarch, index, t, excelParams, sheet, workbook, rowHeight, 0)[0];
                tempList.add(t);
                if (index >=MAX_NUM) {
                    break;
                }
            }
            if (entity.getFreezeCol() != 0) {
                sheet.createFreezePane(entity.getFreezeCol(), 0, entity.getFreezeCol(), 0);
            }

            mergeCells(sheet, excelParams, titleHeight);

            its = dataSet.iterator();
            for (int i = 0, le = tempList.size(); i < le; i++) {
                its.next();
                its.remove();
            }
            if (LOGGER.isDebugEnabled()) {
LOGGER.debug("List data more than max ,data size is {}", dataSet.size());
            }
            // 发现还有剩余list 继续循环创建Sheet
            if (dataSet.size() > 0) {
                createSheetForMap(workbook, entity, entityList, dataSet);
            } else {
                // 创建合计信息
                addStatisticsRow(getExcelExportStyler().getStyles(true, null), sheet);
            }

        } catch (Exception e) {
LOGGER.error(e.getMessage(), e);
            throw new ExcelExportException(ExcelExportEnum.EXPORT_ERROR, e.getCause());
        }
    }

第三步：设置导出文件的时候自动新增序号

ExportParams params = new ExportParams();

params.setAddIndex(true);

注意事项：ExcelExportUtil需要使用我们自己定义的(不要使用easyPoi的)，ExcelExportUtil.exportExcel()中的 ExcelExportService 一定要使用我们自己定义的SubExcelExportService详细参考上图中的示例。