产品需求：

前端上传个csv 或 excel 文件，文件共4列，验证文件大小，类型，文件名长度，文件内容，如果某行某个单元格数据验证不通过，就把错误信息放到这行第五列，然后把带有错误信息的文件，返回给前端。

    @ApiOperation(value = "上传新增")@PostMapping(path = "uploadFile")public ResultMsg<?> uploadExcelFile(@RequestParam("file") MultipartFile file) throws IOException {if (file.getOriginalFilename().length() > 256) {return ResultMsg.failed("文件名超长");}if (file.getSize() > 3 * 1024 * 1024) {return ResultMsg.failed("文件太大");}String fileType = Optional.ofNullable(file.getOriginalFilename()).map(name -> name.substring(name.lastIndexOf("."))).orElse(null);if (!".xls".equalsIgnoreCase(fileType) && !".xlsx".equalsIgnoreCase(fileType) && !".csv".equalsIgnoreCase(fileType)) {return ResultMsg.failed("仅支持 [xls xlsx csv] 格式");}StyleOfWritingExcelDTO dto = null;try {dto = this.validateAndReadExcel(file.getInputStream());} catch (IOException e) {throw new RuntimeException(e);}if (dto.getHasError()) {ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();EasyExcel.write(byteArrayOutputStream, StyleOfWritingExcelModel.class)
//                        .excelType(ExcelTypeEnum.XLSX).sheet("sheet1").doWrite(dto.getStyleOfWritingExcelModelList());String base64Str = Base64.getEncoder().encodeToString(byteArrayOutputStream.toByteArray());Map<Object, Object> base64Map = new HashMap<>();base64Map.put("errStr", "文件内容不合格");base64Map.put("fileData", base64Str);return ResultMsg.failed(4001, "文件内容不合格", base64Map);}if (dto.getStyleOfWritingExcelModelList().isEmpty()) return ResultMsg.failed("文件内容为空");saveData(dto.getStyleOfWritingExcelModelList());return ResultMsg.success();}private StyleOfWritingExcelDTO validateAndReadExcel(InputStream inputStream) {StyleOfWritingExcelDTO result = new StyleOfWritingExcelDTO();List<StyleOfWritingExcelModel> dataList = new ArrayList<>();EasyExcel.read(inputStream, StyleOfWritingExcelModel.class, new AnalysisEventListener<StyleOfWritingExcelModel>() {@Overridepublic void invoke(StyleOfWritingExcelModel styleOfWritingExcelModel, AnalysisContext analysisContext) {StringBuilder errorInfo = new StringBuilder();CategoryEntity firstCategory = null;if (StringUtils.isBlank(styleOfWritingExcelModel.getFirstCategoryName())) {errorInfo.append("品类不能为空；");} else if (styleOfWritingExcelModel.getFirstCategoryName().length() > 50) {errorInfo.append(String.format("品类名长度超限，限制最大[%d]字符；", 50));} else {firstCategory = this.getCategoryCode(styleOfWritingExcelModel.getFirstCategoryName());if (ObjectUtils.isEmpty(firstCategory))errorInfo.append(String.format("品类在库里未找到；"));elsestyleOfWritingExcelModel.setFirstCategory(firstCategory.getCode());}CategoryEntity secondCategory = null;if (StringUtils.isBlank(styleOfWritingExcelModel.getSecondCategoryName())) {errorInfo.append("二级品类不能为空; ");} else if (styleOfWritingExcelModel.getSecondCategoryName().length() > 50) {errorInfo.append(String.format("二级品类名长度超限，限制最大[%d]字符", 50));} else {secondCategory = this.getCategoryCode(styleOfWritingExcelModel.getSecondCategoryName());if (ObjectUtils.isEmpty(secondCategory))errorInfo.append(String.format("二级品类在库里未找到；"));elsestyleOfWritingExcelModel.setSecondCategory(secondCategory.getCode());}if (ObjectUtils.isNotEmpty(firstCategory) && ObjectUtils.isNotEmpty(secondCategory)) {if (!firstCategory.getCode().equals(secondCategory.getParentCode())) {errorInfo.append(String.format("二级品类 和 品类 不匹配"));}}if (StringUtils.isBlank(styleOfWritingExcelModel.getContent())) {errorInfo.append("内容不能为空; ");} else if (styleOfWritingExcelModel.getContent().length() > 3000) {errorInfo.append(String.format("内容长度超限，限制最大[%d]字符", 3000));}styleOfWritingExcelModel.setErrorInfo(errorInfo.toString());dataList.add(styleOfWritingExcelModel);if (!result.getHasError() && StringUtils.isNotBlank(errorInfo.toString())) {result.setHasError(true);}}private CategoryEntity getCategoryCode(String categoryName) {List<CategoryEntity> categoryList = categoryService.list(new QueryWrapper<CategoryEntity>().lambda().eq(CategoryEntity::getName, categoryName));return categoryList.stream().findFirst().orElse(null);}@Overridepublic void doAfterAllAnalysed(AnalysisContext context) {// 解析完成后的操作}}).sheet().doRead();result.setStyleOfWritingExcelModelList(dataList);return result;}返回：{"code": 4001,"message": "文件内容不合格","data": {"fileData": 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errStr": "文件内容不合格"},"timestamp": 63417752000000
}