打包下載下傳zip檔案

public void downloadAttachZip(Long contId, HttpServletResponse response, HttpServletRequest request) {

    InputStream in  = null;
    OutputStream os = null;
    ZipOutputStream zos = null ;

    try{
        ContractDto contract = contractAgent.getContractDtoByContId(contId).getData();
        List<ContractAttachDto> attachList = contractAttachAgent.getAttachListByContId(contId).getData();
        String fileName = contract.getSideCompanyName() + "_" + contract.getContCode() + DateFormatUtils.format(new Date(),"yyyy-MM-dd") + ".zip";
        String a = "a";
        response.reset();
        response.setCharacterEncoding("utf-8");
        response.setContentType("multipart/form-data");
        // 設定導出形式
        response.setContentType("application/OCTET-STREAM");//下載下傳流

        //response.setContentType("application/vnd.ms-excel");//下載下傳Excel時用(告訴浏覽器下載下傳的是Excel)
        // 設定下載下傳的檔案名稱
        response.setHeader("Content-Disposition",
                "attachment;fileName=" + new String(fileName.getBytes("utf-8"), "ISO-8859-1"));
        if(os == null)
        os = response.getOutputStream();
        // 建立outputstream   zos = new ZipOutputStream(out); out為response産生
        zos = new ZipOutputStream(os);
        for(ContractAttachDto attach : attachList){
            if(attach.getAttachTypeId() == 1){
                //1連接配接ftp伺服器 擷取inputstream
                in = new URL(attach.getContAttachLink()).openConnection().getInputStream();
                byte[] buf = new byte[2048];
                zos.putNextEntry(new ZipEntry(attach.getContAttachName()));
                int len;
                while ((len = in.read(buf)) != -1){
                    zos.write(buf, 0, len);
                }
                zos.closeEntry();
                in.close();
            }
        }
    } catch (Exception e) {
        throw new RuntimeException("zip error from ZipUtils",e);
    }finally{
        if(zos != null){
            try {
                zos.close();
            } catch (Exception e) {
                e.printStackTrace();
            } /*finally{
                try{
                    os.close();
                } catch (Exception e){
                    e.printStackTrace();
                }
            }*/

        }

    }
}