How do you upload a file to an FTP server?

Question

I created a function to download files from an FTP server that I have access to. How would I upload files back to the FTP server?

Below is the download_files method i used:

public static void download_files(String un, String pw, String ip, String dir, String fn, String fp){      URLConnection con;     BufferedInputStream in = null;     FileOutputStream out = null;      try{         URL url = new URL("ftp://"+un+":"+pw+"@"+ip+"/"+dir+"/"+fn+";type=i");         con = url.openConnection();         in = new BufferedInputStream(con.getInputStream());         out = new FileOutputStream(fp+fn);          int i = 0;         byte[] bytesIn = new byte[1024];          while ((i = in.read(bytesIn)) >= 0) {             out.write(bytesIn, 0, i);         }      }catch(Exception e){         System.out.print(e);         e.printStackTrace();         System.out.println("Error while FTP'ing "+fn);     }finally{         try{             out.close();             in.close();         }catch(IOException e){             e.printStackTrace();             System.out.println("Error while closing FTP connection");         }     } } 

Answer 1

Use the FTPClient Class from the Apache Commons Net library.

This is a snippet with an example:

FTPClient client = new FTPClient(); FileInputStream fis = null;  try {     client.connect("ftp.domain.com");     client.login("admin", "secret");      //     // Create an InputStream of the file to be uploaded     //     String filename = "Touch.dat";     fis = new FileInputStream(filename);      //     // Store file to server     //     client.storeFile(filename, fis);     client.logout(); } catch (IOException e) {     e.printStackTrace(); } finally {     try {         if (fis != null) {             fis.close();         }         client.disconnect();     } catch (IOException e) {         e.printStackTrace();     } } 

Snippet taken from http://www.kodejava.org/examples/356.html

Answer 2

I have used the EDT FTP package, a free GPL library for FTP in Java: http://www.enterprisedt.com/products/edtftpj/overview.html

Here is a code sample, from the Demo.java class they provide:

ftp = new FTPClient(); ftp.setRemoteHost("hostname");  // connect ftp.connect();  // login ftp.login("user", "password");  // set up passive ASCII transfers ftp.setConnectMode(FTPConnectMode.PASV); ftp.setType(FTPTransferType.ASCII);  // get directory and print it to console             String[] files = ftp.dir(".", true); for (int i = 0; i < files.length; i++)     log.debug(files[i]);  // copy file to server  ftp.put("test.txt", "test.txt");  // copy file from server ftp.get("test.txt" + ".copy", "test.txt");  // delete file from server ftp.delete("test.txt");  // Shut down client                 ftp.quit();