关于把byte[]还原成图片的.关键是不经过磁盘,该怎么处理

    public void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        String adname=request.getParameter("adname");        ApplicationContext App=WebApplicationContextUtils.getWebApplicationContext(request.getSession().getServletContext());        AdDao adDao=(AdDao)App.getBean("adDao");        Ad ad=adDao.findAd(adname);        byte images[]=ad.getAdimage();                response.setContentType("image/jpeg");           InputStream in=new ByteArrayInputStream(images);        OutputStream toClient=response.getOutputStream();             int len;        byte[] buf=new byte[1024];           while((len =in.read(buf,0,1024))!=-1){           toClient.write(buf,0,len);           }        toClient.close();