【Java】使用模板方法模式设计EasyExcel批量导入导出

【一】需求描述

导入导出使用的是EasyExcel
（1）批量导出
支持列表的全部导出和选中导出

（2）下载批量导入模板

（3）批量导入
首先是上传文件到系统管理平台，返回fileId，然后导入接口传参fileId实现文件解析，步骤如下
1-获取模板文件
2-校验模板文件表头
3-校验文件格式并读取文件数据
4-校验数据，每一行数据的错误校验信息会拼在一起，放在最后一个errorMsg字段里
5-如果任意一行errorMsg不为空，导出异常数据模板，如果没有errorMsg，则批量保存数据

【二】痛点分析

每个功能板块要实现导入导出功能的时候，都要把上述的三个接口流程实现一遍，非常繁琐，并且代码冗余。希望使用模板方法模式把导入导出可复用部分的代码封装起来，而数据校验和批量保存等逻辑交给具体的实现类去实现。

以此达到模板方法封装复用和流程标准化的目的

【三】准备工作

【1】创建导入导出文件模板和对应的常量

【2】创建导入导出专用的Vo实体类

（1）导入实体类
有errorMsg字段

@Data
public class LogicIndExcelVOExt {@ExcelProperty(index = 0, value = "*指标主题")private String indexThemeDirectionNames;@ExcelProperty(index = 1, value = "*逻辑指标编号")private String indexCode;@ExcelProperty(index = 2, value = "*逻辑指标中文名称")private String indexName;@ExcelProperty(index = 3, value = "*指标类型")private String indexTypeName;@ExcelProperty(index = 4, value = "依赖指标编号")private String relyIndexCode;@ExcelProperty(index = 5, value = "派生维度")private String derivedDim;@ExcelProperty(index = 6, value = "*业务定义")private String businessDef;@ExcelProperty(index = 7, value = "*业务口径")private String businessCali;@ExcelProperty(index = 8, value = "*统计维度")private String statisticalDim;@ExcelProperty(index = 9, value = "*统计规则")private String statisticalRuleName;@ExcelProperty(index = 10, value = "*统计频率")private String statPeriodName;@ExcelProperty(index = 11, value = "*常用度量")private String measureType;@ExcelProperty(index = 12, value = "常用度量单位")private String unit;@ExcelProperty(index = 13, value = "精度")private String precision;@ExcelProperty(index = 14, value = "应用场景")private String useScope;@ExcelProperty(index = 15, value = "是否监管报送指标")private String reIndexFlagName;@ExcelProperty(index = 16, value = "是否手工指标")private String handIndexFlagName;@ExcelProperty(index = 17, value = "*业务归口部门")private String handleDeptName;@ExcelProperty(index = 18, value = "开放类型")private String shareTypeName;@ExcelProperty(index = 19, value = "安全等级")private String securityLevelName;@ExcelProperty(index = 20, value = "所属系统路径")private String sysPath;@ExcelProperty(index = 21, value = "*指标技术口径")private String indTechCali;@ExcelProperty(value = "错误信息提示", index = 22)private String errorMsg;
}

（2）导出实体类

@Data
public class LogicIndExcelExportVOExt{@ExcelProperty(index = 0, value = "*指标主题")private String indexThemeDirectionNames;@ExcelProperty(index = 1, value = "*逻辑指标编号")private String indexCode;@ExcelProperty(index = 2, value = "*逻辑指标中文名称")private String indexName;@ExcelProperty(index = 3, value = "*指标类型")private String indexTypeName;@ExcelProperty(index = 4, value = "依赖指标编号")private String relyIndexCode;@ExcelProperty(index = 5, value = "派生维度")private String derivedDim;@ExcelProperty(index = 6, value = "*业务定义")private String businessDef;@ExcelProperty(index = 7, value = "*业务口径")private String businessCali;@ExcelProperty(index = 8, value = "*统计维度")private String statisticalDim;@ExcelProperty(index = 9, value = "*统计规则")private String statisticalRuleName;@ExcelProperty(index = 10, value = "*统计频率")private String statPeriodName;@ExcelProperty(index = 11, value = "*常用度量")private String measureType;@ExcelProperty(index = 12, value = "常用度量单位")private String unit;@ExcelProperty(index = 13, value = "精度")private String precision;@ExcelProperty(index = 14, value = "应用场景")private String useScope;@ExcelProperty(index = 15, value = "是否监管报送指标")private String reIndexFlagName;@ExcelProperty(index = 16, value = "是否手工指标")private String handIndexFlagName;@ExcelProperty(index = 17, value = "*业务归口部门")private String handleDeptName;@ExcelProperty(index = 18, value = "开放类型")private String shareTypeName;@ExcelProperty(index = 19, value = "安全等级")private String securityLevelName;@ExcelProperty(index = 20, value = "所属系统路径")private String sysPath;@ExcelProperty(index = 21, value = "*指标技术口径")private String indTechCali;
}

【四】模板方法实现过程

【1】创建抽象父类

创建抽象类GlobalExcelHandleService

@Service
@Slf4j
public abstract class GlobalExcelHandleService {}

【2】批量导出

	public abstract String getExportTempName();/*** 数据导出* @param response* @param excelName* @param sheetName* @param clazz* @param data* @throws IOException*/public <T> void dataExport(HttpServletResponse response, String excelName, String sheetName, Class<T> clazz, List<T> data) throws IOException {if (ObjectUtil.isNull(clazz)) {log.info(ExcelUtil.LOG_INFO);}response.setContentType(ExcelUtil.MULTIPART_OCTET_STREAM_CHARSET);String en = URLEncoder.encode(excelName, ExcelUtil.UTF_8);// 防止中文乱码response.setHeader(ExcelUtil.CONTENT_DISPOSITION, ExcelUtil.ATTACHMENT_FILENAME + en + ExcelTypeEnum.XLSX.getValue());// 模版文件ClassPathResource classPathResource = new ClassPathResource(getExportTempName());InputStream inputStream = classPathResource.getStream();ExcelWriter excelWriter =EasyExcelFactory.write(response.getOutputStream()).withTemplate(inputStream).excelType(ExcelTypeEnum.XLSX).build();WriteSheet writeSheet = EasyExcelFactory.writerSheet(0, sheetName).needHead(false).build();writeSheet.setExcludeColumnFieldNames(ListUtil.of("errorMsg"));excelWriter.write(data, writeSheet);excelWriter.finish();}

【3】下载导入模板

	public abstract String getImportTempName();/*** 下载导入模板文件* @param response* @return*/public ApiResponse<Void> downloadImportTemp(HttpServletResponse response) {YtFileUtil.downloadTemplate(response, this.getClass().getClassLoader(), getImportTempName());return ApiResponse.ok();}

【4】批量导入

    @Autowiredprivate FileFeignClient fileFeignClient;public abstract String getErrorMsgTempName();public abstract <T,U> void verify (List<T> excelVOS, List<U> importDataList);public abstract <T> void saveImportDatas(List<T> importDataList);/*** 根据文件id从系统管理获取导入文件* @param fileId* @return*/public File getImportFileById (Long fileId) {if (fileId == null) {throw new YTRuntimeException("未传入文档");}ResultResp<FileInfo> responseApiResponse = fileFeignClient.getById(fileId);FileInfo data = responseApiResponse.getData();if (ObjectUtils.isEmpty(data)) {throw new YTRuntimeException("无文件");}File tmpFile = FileUtils.createTmpFile(data.getFileName());MultipartFile importMultipartFile = ExcelUtils.getTempMultipartFile(data.getFileUrl(),false);try {importMultipartFile.transferTo(tmpFile);} catch (Exception e) {log.info("文件转换失败：{}",e);throw new YTRuntimeException("文件转换失败");}return tmpFile;}public <T> void checkImportFileHead (File tmpFile, Class<T> excelVoClass) {// 校验文件中的表头是否匹配List<Map<Integer, String>> sheet0List = Lists.newArrayList();try {sheet0List = IndIndexExcelListener.getDataList(tmpFile, 0, 2);} catch (Exception e) {log.info("导入文件表头解析失败：{}",e);throw new YTRuntimeException("导入文件表头解析失败");}if (CollectionUtils.isNotEmpty(sheet0List)) {Map<Integer, String> indexAndNmMapSheet0 = sheet0List.get(0);ApiResponse<Void> shee0tHeadResponse = this.indHeadCheck(indexAndNmMapSheet0,excelVoClass);StringBuilder sb = new StringBuilder();if (ExceptionCode.INTERNAL_SERVER_ERROR.getCode() == shee0tHeadResponse.getCode()) {sb.append(shee0tHeadResponse.getMessage());}if (StringUtils.isNotBlank(sb.toString())) {throw new YTRuntimeException(sb.toString());}} else {throw new YTRuntimeException("请检查上传文件的准确性");}}public <T> ApiResponse<Void> indHeadCheck(Map<Integer, String> indexAndNmMapSheet0, Class<T> importClass) {ApiResponse<Void> shee0tHeadResponse = ExcelUtil.invokeHeadMap("模板", indexAndNmMapSheet0, importClass);return shee0tHeadResponse;}public <T> List<T> readTempFileData (File tmpFile, Class<T> excelVoClass) {String name = tmpFile.getName();String extension = FilenameUtils.getExtension(name);// 读取文件到实体类List<T> excelVOS = new ArrayList<>();if (ListUtil.of("XLSX", "XLS").contains(extension.toUpperCase())) {EasyExcel.read(tmpFile, excelVoClass, new PageReadListener<T>(excelVOS::addAll)).sheet().headRowNumber(3).doRead();} else {throw new YTRuntimeException("文件格式不正确");}if (CollectionUtil.isEmpty(excelVOS)) {throw new YTRuntimeException("读取数据为空");}return excelVOS;}/*** 筛选出errorMsg字段不为空的T集合* @param excelVOS 包含errorMsg字段的VO对象集合* @param <T> 泛型类型（需包含errorMsg字段）* @return 筛选后的T集合*/public <T> List<T> filterNonEmptyErrorMsg(List<T> excelVOS) {if (excelVOS == null || excelVOS.isEmpty()) {return Lists.newArrayList(); // 空集合处理}// 反射获取errorMsg字段（从第一个非空对象提取）Field errorMsgField = getErrorMsgField(excelVOS);if (errorMsgField == null) {return Lists.newArrayList(); // 无errorMsg字段时返回空集合}// 使用Stream流筛选return excelVOS.stream().filter(vo -> vo != null) // 过滤null对象.filter(vo -> isErrorMsgValid(vo, errorMsgField)) // 过滤errorMsg为空的记录.collect(Collectors.toList()); // 收集结果}/*** 反射获取errorMsg字段（支持private字段）*/public <T> Field getErrorMsgField(List<T> excelVOS) {// 从集合中第一个非空对象获取类信息return excelVOS.stream().filter(vo -> vo != null).findFirst().map(vo -> {try {Field field = vo.getClass().getDeclaredField("errorMsg");field.setAccessible(true); // 允许访问私有字段return field;} catch (NoSuchFieldException e) {log.info("类 " + vo.getClass().getSimpleName() + " 不存在errorMsg字段");return null;}}).orElse(null); // 集合全为空时返回null}/*** 判断errorMsg字段是否有效（不为null且非空字符串）*/public <T> boolean isErrorMsgValid(T vo, Field errorMsgField) {try {Object value = errorMsgField.get(vo);// 不为null，且不是空字符串（去除首尾空格后仍有内容）return value != null && !value.toString().trim().isEmpty();} catch (IllegalAccessException e) {log.info("访问errorMsg字段失败：" + e.getMessage());return false;}}public <T> SysFileResponse exportErrorMsgData (List<T> excelVOS) throws IOException {String parentDir = IndexSystemConstant.getTempFileRoot(DateUtil.format(new Date(), DatePattern.PURE_DATE_FORMAT), IndexSystemConstant.INDEX_TRANSFER_DIR);FileUtil.mkdir(parentDir);String excelName = YtFileUtil.getExcelName("导入异常");File file = new File(StrUtil.format("{}/{}", parentDir, excelName));// 模版文件ClassPathResource classPathResource = new ClassPathResource(getErrorMsgTempName());InputStream errMsgInputStream = classPathResource.getStream();EasyExcel.write(file).withTemplate(errMsgInputStream).excelType(ExcelTypeEnum.XLSX).needHead(false).sheet().doWrite(excelVOS);FileInfo fileInfo = YtFileUtil.uploadFile(file, FileEnum.INDEX_DIRECTION);SysFileResponse sysFileResponse = new SysFileResponse();sysFileResponse.setFileInfo(fileInfo);sysFileResponse.setHasError(true);return sysFileResponse;}/*** 数据导入* @param fileId* @param excelVoClass* @return* @throws IOException*/public <T> SysFileResponse dataImport(Long fileId, Class<T> excelVoClass) throws IOException {// 获取模板文件log.info("开始下载模板文件");File tmpFile = getImportFileById(fileId);// 校验模板文件表头log.info("开始校验模板文件表头");checkImportFileHead(tmpFile, excelVoClass);// 读取文件数据log.info("开始读取文件数据");List<T> excelVOS = readTempFileData(tmpFile, excelVoClass);// 校验数据log.info("开始校验文件数据");List<T> importDataList = Lists.newArrayList();verify(excelVOS,importDataList);// 导出异常数据模板List<T> errorMsgExcelVOS = filterNonEmptyErrorMsg(excelVOS);long count = errorMsgExcelVOS.size();if (count != 0) {log.info("开始导出异常数据");return exportErrorMsgData(excelVOS);}log.info("开始保存导入数据");saveImportDatas(importDataList);SysFileResponse sysFileResponse = new SysFileResponse();sysFileResponse.setImportCount(importDataList.size());return sysFileResponse;}

【5】ExcelUtil添加校验excel表头的方法

    public static ApiResponse<Void> invokeHeadMap(String sheetNm, Map<Integer, String> headMap, Class clazz) {/*count 记录模板表头有几个，用以判断用户导入的表格是否和模板完全一致如果用户导入表格较模板的表头多，但其余符合模板，这样不影响则不需要*/int count = 0;// 获取数据实体的字段列表Field[] fields = clazz.getDeclaredFields();// 遍历字段进行判断for (Field field : fields) {// 获取当前字段上的ExcelProperty注解信息ExcelProperty fieldAnnotation = field.getAnnotation(ExcelProperty.class);// 判断当前字段上是否存在ExcelProperty注解if (fieldAnnotation != null) {++count;// 存在ExcelProperty注解则根据注解的index索引到表头中获取对应的表头名String headName = headMap.get(fieldAnnotation.index());// 判断表头是否为空或是否和当前字段设置的表头名不相同String fieldName = fieldAnnotation.value()[0];if (!ObjectUtil.equals("错误信息提示", fieldName)) {if (StringUtils.isEmpty(headName) || ObjectUtil.isNull(headName) || !ObjectUtil.equals(headName, fieldName)) {// 如果为空或不相同，则抛出异常不再往下执行throw new YTRuntimeException("模板错误，请检查" + sheetNm + "sheet页下的表头的【" + headName + "】列，应为【" + fieldName + "】");//return ApiResponse.fail("模板错误，请检查表头的【" + headName + "】列，应为【"+fieldName+"】");}} else {--count;}}}// 判断用户导入表格的标题头是否完全符合模板List<String> headNameList = headMap.values().stream().filter(it -> ObjectUtil.isNotEmpty(it)).collect(Collectors.toList());if (count != headNameList.size()) {throw new YTRuntimeException(sheetNm+"模板错误，请检查导入模板");}return ApiResponse.ok();}

【五】实现某个功能的导入导出

（1）继承抽象父类GlobalExcelHandleService
（2）重写抽象方法
（3）调用父类方法

案例代码如下：

【1】Controller层

/*** 下载导入逻辑指标模板** @param response* @return*/@GetMapping("/download")@Operation(summary = "下载导入逻辑指标模板", description = "下载导入逻辑指标模板")public ApiResponse<Void> download(HttpServletResponse response) {return indLogicIndexAppService.download(response);}/*** 导出指标列表** @param queryRequest 参数* @return 导出结果* @throws IOException IOException*/@PostMapping(value = "/export")@Operation(summary = "导出指标列表", description = "导出指标列表")public ApiResponse<String> export(@RequestBody @Valid IndLogicIndexQueryRequest queryRequest, HttpServletResponse response) throws IOException {return indLogicIndexAppService.export(queryRequest, response);}/*** 导入** @param fileId 文件* @return 返回响应结果*/@ResponseBody@PostMapping(value = "/{file_id}/import")@Operation(summary = "导入", description = "导入")public ApiResponse<SysFileResponse> importIndex(@PathVariable(name = "file_id") Long fileId) throws IOException {return indLogicIndexAppService.importIndex(fileId);}

【2】AppService层

@Service
@AllArgsConstructor
@Slf4j
public class IndLogicIndexAppService extends GlobalExcelHandleService {@Overridepublic String getErrorMsgTempName() {return FileConstant.TEMPLATES.concat(FileExtConstant.逻辑指标批量导入异常模板);}@Overridepublic String getExportTempName() {return FileConstant.TEMPLATES.concat(FileExtConstant.逻辑指标批量导出模板);}@Overridepublic String getImportTempName() {return FileConstant.TEMPLATES.concat(FileExtConstant.逻辑指标批量导入模板);}/*** 批量导出* @param request* @param response* @return* @throws IOException*/public ApiResponse<String> export(IndLogicIndexQueryRequest request, HttpServletResponse response) throws IOException {List<IndLogicIndexQueryResponse> list;if (ObjectUtil.isEmpty(request.getIndexIdList())) {// 导出全部request.setIndexType(null);list = indLogicIndexReadModelRepo.query(request);} else {// 导出选中List<IndLogicIndex> indLogicIndexList = indLogicIndexService.queryByIds(request.getIndexIdList()).getData();list = indLogicIndexDTOAssembler.toQueryResponse(indLogicIndexList);}// 数据统一处理fillProps(list);List<LogicIndExcelExportVOExt> indexExcelVOList = Lists.newArrayList();for (IndLogicIndexQueryResponse indLogicIndexQueryResponse : list) {LogicIndExcelExportVOExt logicIndExcelExportVOExt = new LogicIndExcelExportVOExt();BeanUtil.copyProperties(indLogicIndexQueryResponse,logicIndExcelExportVOExt);indindexExcelVOList.add(logicIndExcelExportVOExt);}//导出dataExport(response, "逻辑指标清单", "逻辑指标清单", LogicIndExcelExportVOExt.class, indexExcelVOList);return null;}/*** 下载导入模板文件* @param response* @return*/public ApiResponse<Void> download(HttpServletResponse response) {downloadImportTemp(response);return ApiResponse.ok();}// 批量导入@Overridepublic <T> void saveImportDatas(List<T> importDataList) {if (ObjectUtil.isEmpty(importDataList)) {return;}List<IndLogicIndex> indLogicIndexList = importDataList.stream().map(it->(IndLogicIndex)it).collect(Collectors.toList());indLogicIndexService.importBatchSave(indLogicIndexList);}// 校验数据@Overridepublic <T,U> void verify(List<T> excelVOS, List<U> importDataList) {List<LogicIndExcelVOExt> logicIndExcelVOExts = excelVOS.stream().map(it->(LogicIndExcelVOExt)it).collect(Collectors.toList());// 校验信息int i = 4;for (LogicIndExcelVOExt vo : logicIndExcelVOExts) {IndLogicIndex index = new IndLogicIndex();List<String> errorMsgList = Lists.newArrayList();if (StringUtils.isBlank(vo.getBusinessCali())) {log.info("第{}行业务口径不可为空", i);errorMsgList.add(StrUtil.format("{}{}", "业务口径", FileConstant.ErrorTypeEnum.NULL.getDesc()));} else {index.setBusinessCali(vo.getBusinessCali());}// 省略更多校验细节if (CollectionUtil.isNotEmpty(errorMsgList)) {vo.setErrorMsg(Joiner.on(StringConstants.SEMICOLON).join(errorMsgList));} else {importDataList.add((U) index);}i++;}}}

【六】总结

如果下一个功能要实现导入导出的功能，就可以继承抽象父类，然后重写和调用方法即可，开发人员只需要关注校验逻辑、导出逻辑、导入逻辑即可，而整个方法的流程模板已经实现封装，开发人员不用关注如何配置流程，且实现了大量代码的灵活复用

用到的知识点细节
（1）模板方法设计模式
（2）反射获取errorMsg字段值
（3）泛型参数传参
（4）Java对象多态
（5）抽象类和抽象方法的使用
（6）EasyExcel通过注解校验表头和实体类是否一致
（7）如果导入数据校验失败，可以下载数据和错误信息提示内容，方便修改和重新导入

功能优化点
（1）导入导出和校验比较耗时的操作，可以使用线程池异步执行