打包并下载文件

  CdncontractbillDAO billDAO = new CdncontractbillDAO();

    List billlist = billDAO.findAll();

//要下载的zip文件，名为DownLoad.zip

File zipFile = new File(System.getProperty("cdncharge_pdf")+"DownLoad.zip");

    try {

//用这个构造最终压缩包的输出流 

    ZipOutputStream zipoutStream = new ZipOutputStream(new FileOutputStream(zipFile));

    InputStream is;

    byte[] bufferArea = new byte[1024];//读写缓冲区

//循环所有文件，将文件打包

  for(Object bi : billlist){

      Cdncontractbill bill = (Cdncontractbill)bi;

      File file = new File(bill.getPath());

if(file.exists()){

FileInputStream zipinSource = new FileInputStream(file);

int read = 0;

ZipEntry zipEntry = new ZipEntry(file.getName());

zipoutStream.putNextEntry(zipEntry);//定位到该压缩条目位置，开始写入文件到压缩包中

while((read = zipinSource.read(bufferArea, 0, 1024)) != -1)

{

zipoutStream.write(bufferArea, 0, read);

}

zipoutStream.closeEntry();

zipinSource.close();

}

  }

  zipoutStream.close();

  is = new FileInputStream(zipFile);

  Filedownload.save(is, "", zipFile.getName());

} catch (Exception e) {

e.printStackTrace();

}

    //删除生成的打包文件

    zipFile.delete();