java 将服务器的图片打包下载成.zip ,通过浏览器下载。

我不是女神ヾ 2021-10-09 10:40 306阅读 0赞

public void download(HttpServletRequest request, HttpServletResponse response){
     
                try {
                    String downloadFilename = "中文.zip";//文件的名称
                    downloadFilename = URLEncoder.encode(downloadFilename, "UTF-8");//转换中文否则可能会产生乱码
                    response.setContentType("application/octet-stream");// 指明response的返回对象是文件流
                    response.setHeader("Content-Disposition", "attachment;filename=" + downloadFilename);// 设置在下载框默认显示的文件名
                    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();
                } 
        }

判断服务器上是否有相应的问文件：

String filePath="http://117.51.149.90/videos/"+paramsBean.getEventId()+".mp4";
    			  URL url = new URL(filePath);
    			 HttpURLConnection urlcon = (HttpURLConnection) url.openConnection();
    	         String message = urlcon.getHeaderField(0);
    			 if (StringUtils.hasText(message) && message.startsWith("HTTP/1.1 404")) {
                                    //不存在
    				 map.put("videoPath", "");
    				 }else{
                                     //存在
    					 map.put("videoPath", filePath);
    	             }

判断服务器的方法存在问题：

由于是http地址就相当于每次都要请求服务器  极大的消耗性能和影响查询时间

优化：直接获取地址在服务器那边文件夹直接查询文件是否存在

String filePath = "/home/dc2-user/audi/apache-tomcat-8.5.35/webapps/images/"+fileName+"/" + paramsBean.getEventId() + ".mp4";
    			
    			File file =new File(filePath);
    			if(file.exists()) {
    				map.put("videoPath", filePath);
    			}else {
    				map.put("videoPath", "");
    			}