前言
EasyExcel实现单元格合并的导出。效果如下：
一、EasyExcel是什么？
这个我就不介绍了，阿里出的，但是据说现在EasyExcel停止维护了，不过不要紧，目前依然好用。后期可能被FastExcel替代，开发这个的团队好像就是EasyExcel那一波人。
二、使用步骤
1.引入库
easyExcel依赖引入，注意其实poi依赖也最好引入，但是要注意版本差异。
<dependency><groupId>com.alibaba</groupId><artifactId>easyexcel</artifactId>
</dependency>
2.导出实现
1. controller：
/*** 导出分区工单分类关键指标分析数据（不绕社区）*/@ResourceAction(id = "exportYearMonthParkStageKeyCount", name = "导出分区工单分类关键指标分析数据")@GetMapping("/exportYearMonthParkStageKeyCount")public void exportYearMonthParkStageKeyCount(WorkOrderCountQueryRequestVo requestVo, HttpServletResponse response) {try {// 设置响应头response.setContentType("application/vnd.ms-excel");response.setCharacterEncoding("utf-8");String fileName = URLEncoder.encode(DateUtil.format(DateUtil.date(), DatePattern.PURE_DATETIME_PATTERN) + "关键指标分析导出" + ".xlsx", StandardCharsets.UTF_8).replaceAll("\\+", "%20");response.setHeader("Content-disposition", "attachment;filename=" + fileName);//组织导出数据Map<String, Object> exportDataMap = orderService.exportYearMonthParkStageKeyCount(requestVo);List<List<String>> headList = (List<List<String>>) exportDataMap.get("headList");List<List<Object>> dataList = (List<List<Object>>) exportDataMap.get("dataList");ExcelWriterBuilder excelWriterBuilder = EasyExcel.write(response.getOutputStream());excelWriterBuilder.registerWriteHandler(new CustomCellWriteHeightStrategy((short) 30, (short) 30)).registerWriteHandler(new CustomCellWriteWidthStrategy()).registerWriteHandler(new CustomCellWriteHandler(2,0,dataList.size()));excelWriterBuilder.head(headList).sheet("关键指标分析").doWrite(dataList);} catch (Exception e) {throw new RuntimeException("导出分区工单分类关键指标分析数据失败");}}
2. serviceImpl：
public Map<String, Object> exportYearMonthParkStageKeyCount(WorkOrderCountQueryRequestVo requestVo) {Map<String, Object> dataMap = new HashMap<>();String yearMonthStr = requestVo.getYearMonthStr();String allHead = "关键指标分析-";Integer type = requestVo.getType();String rateHeadName = "";if (type != null){//1计划，2应急if (type == 1){allHead += "计划工单\n";rateHeadName = "计划工单完成率";}if (type == 2){allHead += "应急工单\n";rateHeadName = "应急工单完成率";}}allHead += 
