图片下载压缩

图片下载时判断是否大于1MB，如果大于则将图片压缩50%

String path = tempFilePath + "/" + UUID.randomUUID().toString();

    File destFile = new File(path);
    destFile.mkdirs();
    List<SysAttachment> atts = attachmentService.findAll(UtilPublic.strArrToListLong(StringUtils.split(id, ",")));
    for (SysAttachment att : atts) {
      File srcFile = new File(saveFilePath + "/" + att.getFileName());
      destFile = new File(path + "/" + att.getFileName());
      if (!destFile.exists()) {
        if (srcFile.length() > 1024 * 1024 * 1) { // 大于1M,缩小50%
          Thumbnails.of(srcFile).scale(0.5).toFile(destFile);
        } else {
          FileUtils.copyFile(srcFile, destFile);
        }
      }
    }
    String fileName = path + ".zip";
    response.reset(); // 非常重要
    // 纯下载方式
    response.setContentType("application/x-msdownload");
    response.setHeader("Content-Disposition",
        "attachment; filename=" + new String("附件.zip".getBytes("GBK"), "ISO8859-1"));
    OutputStream out = response.getOutputStream();
    ZipFileUtil.zip(path, fileName);
    IOUtils.write(FileUtils.readFileToByteArray(new File(fileName)), out);
    out.close();
    // 删掉临时目录
    FileUtils.deleteDirectory(new File(path));
    FileUtils.deleteQuietly(new File(fileName));