从网络获取多张二维码图片，压缩打包下载

项目最近有这个小需求，记录一下。

controller层：

/**
     * 批量下载二维码图片
     *
     * @param deviceIdStr
     */
    @RequestMapping("qr_code")
    public void batchDownLoadQrCode(String deviceIdStr, HttpServletResponse response) throws Exception {
        String[] deviceId = deviceIdStr.split(",");
        List<Integer> deviceIds = new ArrayList<>();
        for (String id : deviceId) {
            deviceIds.add(Integer.valueOf(id));
        }
        DeviceQueryForm deviceQueryForm = new DeviceQueryForm();
        deviceQueryForm.setDeviceIds(deviceIds);
        List<Device> deviceList = deviceClient.getDeviceList(deviceQueryForm);

//      生成zip文件
        String name = "qrCode" + System.currentTimeMillis();
        String zipFileName = name + ".zip";
        String projectPath = System.getProperty("user.dir");
        String path = projectPath + File.separator + "qrCode";
        
        File file = new File(path);
        //文件夹不存在则创建
        if (!file.exists()) {
            file.mkdirs();
        }
        //新建一个zip
        File zipFile = new File(path + File.separator + zipFileName);
        ZipOutputStream zipOutputStream = new ZipOutputStream(new FileOutputStream(zipFile));

        for (Device device : deviceList) {
            String imageName = device.getDeviceCode() + ".jpg";

            if (StringUtils.isBlank(device.getQrCodeUrl())) {
                continue;
            }

            URL url = new URL(device.getQrCodeUrl());
            URLConnection conn = url.openConnection();
            conn.setConnectTimeout(3000);
            InputStream inputStream = conn.getInputStream();
            File imageFile = FileUtil.generateImageFile(inputStream, path, imageName);

            FileUtil.generateZip(zipOutputStream, imageFile);

            //删除图片
            if (imageFile.exists()) {
                imageFile.delete();
            }
        }

        zipOutputStream.flush();
        zipOutputStream.close();

        //输出到客户端
        OutputStream out = response.getOutputStream();
        response.reset();
        response.setHeader("Content-Disposition", "attachment;filename=" + zipFileName);
        response.setContentType("application/zip;charset=utf-8");
        response.setCharacterEncoding("UTF-8");
        out.write(FileUtils.readFileToByteArray(zipFile));
        out.flush();
        out.close();
        //删除压缩包
        if (zipFile.exists()) {
            zipFile.delete();
        }
    }

工具类：

package cn.ubox.mbss.ops.backend.utils;

import java.io.*;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

/**
 * @Author: 2YSP
 * @Description:
 * @Date: Created in 2017/12/13
 */
public class FileUtil {
    /**
     * 生成二维码图片
     * @param inputStream
     * @param path
     * @param imageName
     */
    public static File generateImageFile(InputStream inputStream,String path,String imageName){
        FileOutputStream outStream = null;
        File imageFile = null;
        BufferedInputStream bufferStream = null;
        try{
            //创建二维码图片
            imageFile = new File(path + File.separator + imageName);

            outStream = new FileOutputStream(imageFile);
            bufferStream = new BufferedInputStream(inputStream);
            byte[] data = new byte[1024 * 100];
            int len = 0;
            while ((len = bufferStream.read(data)) != -1) {
                //写入数据
                outStream.write(data, 0, len);
            }
        }catch (IOException e){
            e.printStackTrace();
        }finally {
            if (outStream != null){
                try {
                    outStream.flush();
                    outStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (bufferStream != null){
                try {
                    bufferStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return imageFile;
    }

    /**
     * 压缩图片为zip格式
     * @param zipOutputStream
     * @param imageFile
     *
     */
    public static void generateZip(ZipOutputStream zipOutputStream,File imageFile){
        BufferedInputStream bufferStream = null;
        try {
            InputStream input = new FileInputStream(imageFile);
            String zipEntryName = imageFile.getName();
            byte[] bytes = new byte[1024 * 100];// 读写缓冲区
            bufferStream =  new BufferedInputStream(input);// 输入缓冲流

            ZipEntry zipEntry = new ZipEntry(zipEntryName);
            // 定位到该压缩条目位置，开始写入文件到压缩包中
            zipOutputStream.putNextEntry(zipEntry);
            int len = 0;
            while ((len = bufferStream.read(bytes)) != -1) {
                zipOutputStream.write(bytes, 0, len);
            }
        }catch (IOException e){
            e.printStackTrace();
        }finally {
            if (bufferStream != null){
                try {
                    bufferStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

如果大家觉得有需要优化的地方，欢迎留言讨论。