前提

由于业务需要,获取多个pdf的时候需要将多个pdf存入zip类型的压缩包中实现下载,导出的过程使用轮询的方式实现进度查询,每次操作将当前进度存储入redis中,获取进度的接口从redis查询信息,下面只详细展开zip下载的代码

代码实现

这个操作步骤主要分两步

1.生成压缩输出流

返回查询进度的id,操作完成后将把流信息存储入redis,提供下载使用

java
if (!redisUtil.isPing()) {
            throw new BusinessException(ResultCodeEnum.ERR_0x1000.getCode(), "导出失败，Redis服务未连接！");
        }
        String id = StringUtil.generateId();
        redisUtil.set(markKey, id, 3600);
        Map<String, Object> map = new HashMap<>();
        map.put("current", 0);
        map.put("total", list.size());
        String mapkey = markKey + id + ":";
        redisUtil.set(mapkey, map, 3600);
        //单线程线程池
        ThreadPoolExecutor poolExecutor = new ThreadPoolExecutor(1, 1, 60, TimeUnit.SECONDS, new LinkedBlockingQueue<>(), Executors.defaultThreadFactory(), new ThreadPoolExecutor.DiscardPolicy());
        try {
            poolExecutor.execute(() -> {
                List<byte[]> pdfBytesList = new ArrayList<>();
                List<String> filenames=new ArrayList<>();
                for (PatientRequest p : list) {
                    byte[] bytes = null;
                    try {
                        bytes = getPdfByte(p);
                    } catch (Exception e) {
                        log.error(e.getMessage());
                        e.printStackTrace();
                    }
                    Map<String, Object> map1 = redisUtil.get(mapkey, Map.class);
                    map1.put("current", (Integer) map1.get("current") + 1);
                    if (ArrayUtil.isNotEmpty(bytes)) {
                        filenames.add(String.format("%s_%s_%s_%s.pdf", province, name, p.getPatientId(), DateUtil.format(new Date(), "yyyyMMdd")));
                        pdfBytesList.add(bytes);
                    }
                    if (list.indexOf(p) == list.size() - 1) {
                        try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
                             ZipOutputStream zos = new ZipOutputStream(baos)) {
                            for (int i = 0; i < pdfBytesList.size(); i++) {
                                byte[] pdfBytes = pdfBytesList.get(i);
                                ZipEntry entry = new ZipEntry(filenames.get(i));
                                zos.putNextEntry(entry);
                                zos.write(pdfBytes);
                                zos.closeEntry();
                            }
                            zos.flush();
                            zos.close();
                            baos.flush();
                            map1.put("data", Base64.getEncoder().encodeToString(baos.toByteArray()));
                        } catch (IOException e) {
                            // 处理可能的异常
                            e.printStackTrace(); // 实际应用中应使用合适的日志记录方式
                            map1.put("data", null);
                        }
                    }
                    redisUtil.set(mapkey, map1);
                }
            });
        } catch (Exception e) {
            throw new BusinessException(ResultCodeEnum.ERR_0x1000.getCode(), e.getMessage());
        } finally {
            poolExecutor.shutdown();
        }
        return id;

2.web下载压缩包

java

public void downloadBatchPdfZip(String markNo, HttpServletResponse response) {
        String mapkey = markKey + markNo + ":";
        if (!redisUtil.hasKey(mapkey)) {
            throw new BusinessException(ResultCodeEnum.ERR_0x1000.getCode(), "未找到对应数据!");
        }
        Map<String, Object> map = redisUtil.get(mapkey, Map.class);
        String zipBase64 = (String) map.get("data");
        if (StrUtil.isBlank(zipBase64)) {
            throw new BusinessException(ResultCodeEnum.ERR_0x1000.getCode(), "下载压缩包出错!");
        }

        try (ServletOutputStream out = response.getOutputStream()) {
            byte[] bytes = Base64.getDecoder().decode(zipBase64);
            //FileUtils.base64ToFile("d:\\1.zip",Base64.getEncoder().encodeToString(bytes));
            ByteArrayInputStream inputStream = new ByteArrayInputStream(bytes);
            BufferedInputStream bis = new BufferedInputStream(inputStream);
            String fileName = String.format("%s_%s_全病案_%s.zip", province, name, DateUtil.format(new Date(), "yyyyMMdd"));
            response.setContentType("application/zip");
            response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
            IoUtil.copy(bis, out);
        } catch (IOException e) {
            e.printStackTrace();
            throw new BusinessException(ResultCodeEnum.ERR_0x1000.getCode(), "下载压缩包失败!");
        }

    }