Maven依赖 

<!-- 核心库（支持.xls） -->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
</dependency>

<!-- 支持.xlsx格式 -->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
</dependency>

核心概念 

类名	作用	对应格式
SXSSFWorkbook	大数据量导出（流式处理）	.xlsx
Sheet	工作表	通用
Row	行	通用
Cell	单元格	通用

基础操作

private void test() {
        //创建工作簿
		Workbook workbook = new SXSSFWorkbook();
		Sheet sheet = workbook.createSheet();

		//创建表头
        //创建第一行
		Row row = sheet.createRow(0);
        //第一行 第一列
		row.createCell(0).setCellValue("姓名");
        //第一行 第二列
		row.createCell(1).setCellValue("年龄");

        //创建第二行
		Row row1 = sheet.createRow(1);
        //第二行 第一列
		row1.createCell(0).setCellValue("张三");
        //第二行 第二列
		row1.createCell(1).setCellValue("18");

        //创建第三行
		Row row2 = sheet.createRow(2);
        //第三行 第一列
		row2.createCell(0).setCellValue("李四");
        //第三行 第二列
		row2.createCell(1).setCellValue("20");

		try (FileOutputStream fileOutputStream = new FileOutputStream("学生信息.xlsx")) {
			workbook.write(fileOutputStream);
            workbook.close();
		} catch (Exception e) {
            throw new RuntimeException();
		}
	}

封装工具类使用 ExcelUtils

读取文件

ExcelUtils.read(OPCPackage.open(inputStream), 1, (row, index) -> {
	String keyword = ExcelUtils.getString(row.getCell(0));
	String cityName = ExcelUtils.getString(row.getCell(1));
	String positionType = ExcelUtils.getString(row.getCell(2));
	if (StringUtils.isEmpty(keyword) || "未匹配到城市".equals(cityName) || "未匹配到工种".equals(positionType)) {
		return;
	}
	PositionSeoKeywordRequest keywordRequest = PositionSeoKeywordRequest.builder().keyword(keyword)
			.positionType(positionType).cityName(cityName)
			.deleted(0L).createTime(now).updateTime(now).build();
	list.add(keywordRequest);
});

写文件

//创建工作簿实例
Workbook workbook = new SXSSFWorkbook();
// sheet页1-拉新业务看板数据
int sheet1Volume = ExcelUtils.write(
	workbook,
	(page, size) -> this.customerShareRelationRecordService.listCustomerShareSummaries(
			param.getPeriod(), param.getSharerId(), Paging.of(page, size)
	),
	(row, summary, i) -> {
		EmployeeDTO employee = employeesMap.get(summary.getSharerId());
		// sharerId = 0 代表是合计总数
		row.createCell(0).setCellValue(
				summary.getSharerId() == 0L ? "合计" : employee == null ? null : employee.getName()
		);
		row.createCell(1).setCellValue(employee == null ? null : employee.getMobile());
		row.createCell(2).setCellValue(summary.getRegisterCount());
		row.createCell(3).setCellValue(
				summary.getReleasePositionNormalCount() + summary.getReleasePositionAbnormalCount()
		);
		row.createCell(4).setCellValue(summary.getReleasePositionNormalCount());
		row.createCell(5).setCellValue(summary.getReleasePositionAbnormalCount());
	},
	"销售人员", "手机号", "注册人数", "发布职位人数", "发布职位人数-正常用户", "发布职位人数-异常用户"
);
workbook.setSheetName(0, "汇总数据");

// sheet页2-异常用户明细数据
int sheet2Volume = ExcelUtils.write(
	workbook,
	(page, size) -> this.customerShareRelationRecordService.listEachTypeUsers(
			param.getPeriod(), param.getSharerId(), Paging.of(page, size), CustomerShareType.ABNORMAL
	),

	(row, abnormal, i) -> {
		EmployeeDTO employee = employeesMap.get(abnormal.getSharerId());
		row.createCell(0).setCellValue(ObjectUtils.ifNull(employee, EmployeeDTO::getName));
		row.createCell(1).setCellValue(abnormal.getMobile());
		row.createCell(2).setCellValue(DateUtils.format(abnormal.getOperateTime()));
		row.createCell(3).setCellValue(abnormal.getAbnormalMobile());
	},
	"销售人员", "用户登录手机号", "发布职位日期", "发布职位信息填写联系电话"
);
workbook.setSheetName(1, "发布职位人-异常用户明细");

// sheet页3-正常用户明细数据
int sheet3Volume = ExcelUtils.write(
	workbook,
	(page, size) -> this.customerShareRelationRecordService.listEachTypeUsers(
			param.getPeriod(), param.getSharerId(), Paging.of(page, size), CustomerShareType.NORMAL
	),

	(row, abnormal, i) -> {
		EmployeeDTO employee = employeesMap.get(abnormal.getSharerId());
		row.createCell(0).setCellValue(ObjectUtils.ifNull(employee, EmployeeDTO::getName));
		row.createCell(1).setCellValue(abnormal.getMobile());
		row.createCell(2).setCellValue(DateUtils.format(abnormal.getOperateTime()));
		row.createCell(3).setCellValue(abnormal.getAbnormalMobile());
	},
	"销售人员", "用户登录手机号", "发布职位日期", "发布职位信息填写联系电话"
);
workbook.setSheetName(2, "发布职位人-正常用户明细");

// 保存文件
File attachment = new File(this.getExportDirectory(), String.valueOf(exportationId));
try (OutputStream output = new FileOutputStream(attachment)) {
workbook.write(output);
workbook.close();
} catch (IOException e) {
throw new RuntimeException(e);
}
//导出完成
this.exportationService.completeExporting(exportationId, sheet1Volume + sheet2Volume + sheet3Volume);

private File doExportRecruitData(List<PositionEmailSendDTO> positionEmailSendDTOS) {
	File attachment = new File(getExportDirectory(), UUID.randomUUID() + EXCEL_EXTENSION);
	try (Workbook workbook = new SXSSFWorkbook()) {
		Sheet sheet = ExcelUtils.initializeSheet(workbook,EXCEL_HEADERS);
		for (int i = 0, size = positionEmailSendDTOS.size(); i < size; i++) {
			PositionEmailSendDTO label = positionEmailSendDTOS.get(i);
			Row row = sheet.createRow(i+1);
			row.createCell(0).setCellValue(label.getTitle());
			row.createCell(1).setCellValue(label.getDescription());
			row.createCell(2).setCellValue(label.getRegionName());
			row.createCell(3).setCellValue(label.getType().getDescription());
			row.createCell(4).setCellValue(label.getMobile());
		}
		try (OutputStream output = new FileOutputStream(attachment)) {
			workbook.write(output);
			workbook.close();
		}
		return attachment;
	} catch (Exception e) {
		log.error("【招聘数据邮件发送定时器】导出失败:{}",e.getMessage());
		throw new RuntimeException("Failed to export recruitment data", e);
	}
}