压缩流
场景：需要将一些数据，以及这些数据关联的附件压缩下载，数据导出为一个Excel，附件导出到一个文件夹中
这里使用easyexcel 导出excel 从华为云 obs 下载附件
并交给浏览器
public void downloadAllEliminate(HttpServletResponse response) throws IOException {// 响应头的设置response.reset();response.setCharacterEncoding("utf-8");response.setContentType("multipart/form-data");// 设置压缩包的名字// 解决不同浏览器压缩包名字含有中文时乱码的问题String downloadName = System.currentTimeMillis()+".zip";response.setHeader("Content-Disposition", "attachment;fileName=\"" + downloadName + "\"");// 数据List<CurrentTransactionsCountDetailsResult> allEliminate = baseMapper.getAllEliminate();InputStream inputStream = this.getClass().getClassLoader().getResourceAsStream("static/往来挂账-剔除.xlsx");// excel 输出流ByteArrayOutputStream outputStream1 = new ByteArrayOutputStream();ExcelWriter excelWriter = EasyExcel.write(outputStream1).withTemplate(inputStream).build();WriteSheet writeSheet = EasyExcel.writerSheet("往来挂账明细").build();FillConfig fillConfig = FillConfig.builder().direction(WriteDirectionEnum.VERTICAL).forceNewRow(Boolean.TRUE).build();excelWriter.fill(new FillWrapper("list", allEliminate), fillConfig, writeSheet);excelWriter.finish();//关闭流// 设置压缩流：直接写入response，实现边压缩边下载ZipOutputStream zipos = null;try {zipos = new ZipOutputStream(new BufferedOutputStream(response.getOutputStream()));zipos.setMethod(ZipOutputStream.DEFLATED); // 设置压缩方法} catch (Exception e) {e.printStackTrace();}// 将excel写入zipos.putNextEntry(new ZipEntry("往来挂账-剔除.xlsx"));byte[] buffer = outputStream1.toByteArray();zipos.write(buffer, 0, buffer.length);zipos.closeEntry();// 拿到所有文件, 并写入压缩流List<Map<String, String>> allEliminateFileName = baseMapper.getAllEliminateFileName();String filePath = "附件/";for (Map<String, String> stringStringMap : allEliminateFileName) {InputStream is = obsUtil.getInputStream(stringStringMap.get("path"), CurrentTransactionsCountController.filePath);zipos.putNextEntry(new ZipEntry(filePath + stringStringMap.get("fileName")));byte[] bufferTo = new byte[2048]; // 更大的缓冲区通常能提高效率int length;while ((length = is.read(bufferTo)) != -1) {zipos.write(bufferTo, 0, length); // 直接写入zipos}is.close();zipos.closeEntry();}// 确保所有条目都已写入，并刷新缓冲区zipos.flush();// 关闭流try {zipos.close();} catch (IOException e) {e.printStackTrace();}}
