easyExcel导出功能（excel模版文件导出）

1、使用模版格式设置excel文件，数据对象使用参数化

2、读取模版文件流，写入准备好的数据集合，支持多个sheet一次写入

2、支持多文件打包下载和单文件下载，下面是示例代码

@Override
    public void exportBatch(List<Long> idsList, HttpServletResponse response) {
        // 判断是否多条 多条 进行压缩下载 单挑直接下载
        if (idsList.isEmpty()) {
            throw new ParamValidateException(ValidatorExceptionEnum.MISSING_PARAMETER_EXCEPTION, "ids参数不能空");
        }
        //excel数据源查询
        List<InvoiceExport> invoiceExports = baseMapper.selectExport(idsList);

        if (CollectionUtil.isEmpty(invoiceExports)) {
            throw new FileException(FILE_NOT_FOUND, "未查询到开票业务数据");
        }

        Long templateId = ConfigContext.me().getConfigValue(InvoiceConstant.INVOICE_EXPORTBATCH_KEY, Long.class);
        SysFileInfoResponse sysFileInfo = fileInfoApi.getFileInfoWithoutContent(templateId);
        if (sysFileInfo == null) {
            throw new FileException(NOT_EXISTED);
        }
        byte[] fileBytes = fileApi.getFileBytes(FileConfigExpander.getDefaultBucket(), sysFileInfo.getFileObjectName());
        if (fileBytes.length < 1) {
            throw new FileException(FILE_STREAM_ERROR, "获取文件失败，请检查模板是否存在");
        }
        if (invoiceExports.size() < 2 ) {
            try (InputStream is = new ByteArrayInputStream(fileBytes)) {
                String fileName = FileUtils.genFileNameByTime("开票单", ".xlsx");
                String downfileName = URLEncoder.encode(fileName, "UTF-8").replaceAll("\\+", "%20");
                // 1. 设置响应头，告诉浏览器这是一个文件下载
                // 1.1 设置 Content-Type 为 Excel 文件类型
                response.setContentType("application/vnd.ms-excel");
                // 1.2 设置字符编码
                response.setCharacterEncoding("utf-8");
                response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + downfileName);
                try (ExcelWriter excelWriter = EasyExcel.write(response.getOutputStream())
                        .withTemplate(is).excelType(ExcelTypeEnum.XLSX).build()) {
                    WriteSheet writeSheet1 = EasyExcel.writerSheet("1-发票信息").build();
                    WriteSheet writeSheet2 = EasyExcel.writerSheet("2-发票明细信息").build();
                    FillConfig fillConfig = FillConfig.builder().forceNewRow(Boolean.TRUE).build();
                    excelWriter.fill(invoiceExports.get(0), fillConfig, writeSheet1);
                    excelWriter.fill(invoiceExports.get(0).getDetails(), fillConfig, writeSheet2);
                }

            } catch (Exception e) {
                throw new FileException(DOWNLOAD_FILE_ERROR, "请重试");
            }
        } else {
            // 则打压缩包
            // 多条数据，需要生成多个Excel文件并压缩下载
            String zipFileName = FileUtils.genFileNameByTime("开票单批量", ".zip");
            String downZipFileName = null;
            try {
                downZipFileName = URLEncoder.encode(zipFileName, "UTF-8").replaceAll("\\+", "%20");
            } catch (UnsupportedEncodingException e) {
                throw new FileException(DOWNLOAD_FILE_ERROR, "下载文件名错误");
            }

            response.setContentType("application/zip");
            response.setCharacterEncoding("utf-8");
            response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + downZipFileName);

            // 创建临时目录存储Excel文件
            Path tempDir = null;
            try {
                tempDir = Files.createTempDirectory("invoice_export_");
                List<File> tempFiles = new ArrayList<>();

                // 生成每个Excel文件
                for (int i = 0; i < invoiceExports.size(); i++) {
                    InvoiceExport exportData = invoiceExports.get(i);
                    String fileName = FileUtils.genFileNameByTime("开票单_" + (i + 1), ".xlsx");
                    Path tempFile = tempDir.resolve(fileName);
                    File outPut = tempFile.toFile();
                    try (InputStream is = new ByteArrayInputStream(fileBytes);
                         ExcelWriter excelWriter = EasyExcel.write(outPut)
                                 .withTemplate(is).excelType(ExcelTypeEnum.XLSX).build()) {

                        WriteSheet writeSheet1 = EasyExcel.writerSheet("1-发票信息").build();
                        WriteSheet writeSheet2 = EasyExcel.writerSheet("2-发票明细信息").build();
                        FillConfig fillConfig = FillConfig.builder().forceNewRow(Boolean.TRUE).build();
                        excelWriter.fill(exportData, fillConfig, writeSheet1);
                        excelWriter.fill(exportData.getDetails(), fillConfig, writeSheet2);
                        tempFiles.add(outPut);
                    }
                }

                // 创建ZIP输出流并压缩所有文件
                try (ZipOutputStream zipOut = new ZipOutputStream(response.getOutputStream())) {
                    byte[] buffer = new byte[1024];

                    for (File file : tempFiles) {
                        FileInputStream fis = new FileInputStream(file);
                        zipOut.putNextEntry(new ZipEntry(file.getName()));

                        int length;
                        while ((length = fis.read(buffer)) > 0) {
                            zipOut.write(buffer, 0, length);
                        }

                        zipOut.closeEntry();
                        fis.close();
                    }

                    zipOut.finish();
                }

            } catch (Exception e) {
                throw new FileException(DOWNLOAD_FILE_ERROR, "批量导出失败，请重试");
            } finally {
                // 删除临时文件和目录
                if (tempDir != null) {
                    try {
                        Files.walk(tempDir)
                                .sorted(Comparator.reverseOrder())
                                .map(Path::toFile)
                                .forEach(File::delete);
                    } catch (IOException e) {
                        // 记录日志，但不中断主流程
                        log.warn("Failed to delete temporary files: {}", e.getMessage());
                    }
                }
            }
        }
    }