code Java pour télécharger un fichier à partir du serveur

Question

en utilisant le code java dans windows-je télécharger plusieurs fichiers à partir d'un répertoire placé dans un serveur. ces fichiers dans le serveur sont générés séparément. donc je sais pas le nom de ces fichiers. est-il possible de le télécharger en utilisant JAVA et l'enregistrer dans un dossier spécifique.

J'utilise tomcat apache.

Je lis tous les autres threads liés à télécharger le fichier java. Mais aucun d'entre eux satisfaire mes besoins.

Answer 1

Use java.net.URL and java.net.URLConnection classes.

Answer 2

  try {
        // Get the directory and iterate them to get file by file...
        File file = new File(fileName);

        if (!file.exists()) {
            context.addMessage(new ErrorMessage("msg.file.notdownloaded"));
            context.setForwardName("failure");
        } else {
            response.setContentType("APPLICATION/DOWNLOAD");
            response.setHeader("Content-Disposition", "attachment"+ 
                                     "filename=" + file.getName());
            stream = new FileInputStream(file);
            response.setContentLength(stream.available());
            OutputStream os = response.getOutputStream();      
            os.close();
            response.flushBuffer();
        }
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (stream != null) {
            try {
                stream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

Hope you got some idea...

Answer 3

You can use HttpURLConnection to download file over HTTP, HTTPS

Answer 4

It is only possible if server lists directory contents. if it does, your can make an HTTP request to:

http://server:port/folder

that would give you list of files.

Once you have that, you can download individual files by parsing output if this http request.

Answer 5

Hi you can use this following code snippet to down the file directly :

    URL oracle = new URL("http://www.example.com/file/download?");
    BufferedReader in = new BufferedReader(
    new InputStreamReader(oracle.openStream()));

    String inputLine;
    while ((inputLine = in.readLine()) != null)
        System.out.println(inputLine);
    in.close();

Kindly refer about openStream in this [URL] : http://docs.oracle.com/javase/tutorial/networking/urls/readingURL.html

Answer 6

If it is server, then the process must be like using the FTP credentials you have to dosnload the files. This java file download example may help you.