EasyExcel多样式、多数据导出，并获取导出文件流存储

在开发业务中，正常使用EasyExcel的write导出文件流给客户端，客户端就可自行下载。

但在偶尔业务中，可能也需要把write后的文件存储到服务器或者oss或者哪里，不直接把文件流给吐回去。所以我这里给大家提供我本人遇到的情况详情给大家讲解~ （研究了好几天!!! 耐心看）

• 这是我导出的Xlsx文件内容：

步骤1、Controller层

步骤2、这就可以略过~

步骤3、重点来了

步骤4、底下都是步骤3中的的公共方法

@Override
public CommonResponse downloadTickets(HttpServletResponse response, Integer invoiceId) {
    try {
        //首先创建任意一个OutPutStream流
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        //组装header
        OutputStream outputStream = responseSetHeader(response);
        //获取票单模板
        MultipartFile mockMultipartFile = getTemplate();
        //创建Sheet页、填充格式设置
        ExcelWriter excelWriter =   EasyExcel.write(outputStream).file(bos).withTemplate(mockMultipartFile.getInputStream()).build();
        WriteSheet writeSheet = EasyExcel.writerSheet().build();
        FillConfig fillConfig = FillConfig.builder().forceNewRow(Boolean.TRUE).build();
        InvoiceEntity invoiceEntity = invoiceService.getById(invoiceId);
        if (null == invoiceEntity) {
            throw InvoiceException.DATA_NULL_EXCEPTION.newInstance();
        }
        //从oss获取订单文件转为对象 拼接订单数据用到
        byte[] fileByte = ossUtil.getFile(invoiceEntity.getOrderDetailOssUrl());
        if (!ArrayUtils.isNotEmpty(fileByte)) {
            throw InvoiceException.OSS_EXCEPTION.newInstance("订单文件未找到");
        }
        //读取订单数据转List
        List<InvoiceOrderDetailData> invoiceOrderDetailDataList = getOssFileList(fileByte);
        //组装公司信息
        Map<String, Object> map = getStringObjectMap(invoiceEntity);
        //开始读取
        excelWriter.fill(invoiceOrderDetailDataList, fillConfig, writeSheet);
        excelWriter.fill(map, writeSheet);
        //拼接票单落款信息
        List<List<String>> listList = getLists(invoiceEntity.getAmount().toString());
        excelWriter.write(listList, writeSheet);
        excelWriter.finish();
        return CommonResponse.success(getInvoiceTickets(bos));
    } catch (IOException e) {
        log.error("下载票单异常:{}", e);
        throw InvoiceException.OSS_EXCEPTION.newInstance("下载票单异常");
    }
}
---------------------------------------------------------------------------------------
 private OutputStream responseSetHeader(HttpServletResponse response) throws IOException {
        response.setCharacterEncoding("UTF-8");
        response.setHeader(HttpHeaders.CONTENT_TYPE, "application/vnd.ms-excel");
        response.setHeader(HttpHeaders.CONTENT_DISPOSITION, "attachment;filename=invoice.xls");
        // xls
//         response.setContentType("application/vnd.ms-excel");
        // xlsx
//        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
        return response.getOutputStream();
    }
    
-------------------------------------------------------------------------------------- 
private MultipartFile getTemplate() throws IOException {
    String filePath = OssUtil.PATH_TEMPLATE_FILE + "INVOICE_TEMPLATE.xlsx";
    byte[] fileByte = ossUtil.getFile(filePath);
    InputStream inputStream = new ByteArrayInputStream(fileByte);
    MultipartFile mockMultipartFile = new MockMultipartFile(ContentType.APPLICATION_OCTET_STREAM.toString(), inputStream);
    return mockMultipartFile;

}
--------------------------------------------------------------------------------------
private List<InvoiceOrderDetailData> getOssFileList(byte[] fileByte) throws IOException {
    InputStream inputStream = new ByteArrayInputStream(fileByte);
    MultipartFile mockMultipartFile = new MockMultipartFile(ContentType.APPLICATION_OCTET_STREAM.toString(), inputStream);
    BufferedInputStream bufferedInputStream = new BufferedInputStream(mockMultipartFile.getInputStream());
    ExcelListener sheetOneListener = new ExcelListener();
    ExcelReader excelReader = EasyExcel.read(bufferedInputStream).build();
    ReadSheet build0 = EasyExcel.readSheet(0).head(InvoiceOrderDetailData.class).headRowNumber(1).registerReadListener(sheetOneListener).build();
    excelReader.read(build0);
    return sheetOneListener.getRows();
}
--------------------------------------------------------------------------------------
private String getInvoiceTickets(ByteArrayOutputStream bos) {
    //单独把票单存储到oss返回客户端路径
    String invoiceTicketsUrl = "";
    byte[] bytes = bos.toByteArray();
    InputStream sbs = new ByteArrayInputStream(bytes);
    String path = OssUtil.PATH_TEMPLATE_FILE + "INVOICE_TICKETS.xlsx";
    try {
        ossUtil.putObject(path, sbs);
        invoiceTicketsUrl = ossUtil.generatePresignedUrl(path);
    } catch (ApiException e) {
        log.error("票单存储oss错误:{}", e);
        throw InvoiceException.OSS_EXCEPTION.newInstance("票单存储oss错误");
    }
    return invoiceTicketsUrl;
}