應專案要求需要將多個存在某url地址的圖片,打包為zip下載下來
就費勁的研究兩小時，搞定收工,初稿如下

public void download(HttpServletRequest request, HttpServletResponse response){

            try {
                String downloadFilename = "中文.zip";//檔案的名稱
                downloadFilename = URLEncoder.encode(downloadFilename, "UTF-8");//轉換中文否則可能會產生亂碼
 

                response.setContentType("application/octet-stream");// 指明response的返回物件是檔案流 
                response.setHeader("Content-Disposition", "attachment;filename=" + downloadFilename);// 設定在下載框預設顯示的檔名
                ZipOutputStream zos = new ZipOutputStream(response.getOutputStream());
                String[] files = new
 
 String[]{"http://xxxx/xx.jpg","http://xxx/xx.jpg"};
                for (int i=0;i<files.length;i++) {
                    URL url = new URL(files[i]);
                   zos.putNextEntry(new ZipEntry(i+".jpg"));
                   //FileInputStream fis = new FileInputStream(new File(files[i]));  
                   InputStream fis = url.openConnection().getInputStream();   
                   byte
 
[] buffer = new byte[1024];     
                   int r = 0;     
                   while ((r = fis.read(buffer)) != -1) {     
                       zos.write(buffer, 0, r);     
                   }     
                   fis.close();   
                  }  
                zos.flush();     
                zos.close();
            } catch (UnsupportedEncodingException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }  
    }