File upload in Java through FTP

问题:

Im trying to develop a simple java code which will upload some contents from local machine to a server/another machine.I used the below code

import sun.net.ftp.*;
import java.io.*;

public class SftpUpload {
 public static void main(String args[]) {
   String hostname = "some.remote.machine"; //Remote FTP server: Change this
   String username = "user"; //Remote user name: Change this
   String password = "start123"; //Remote user password: Change this
   String upfile = args[0]; //File to upload passed on command line
   String remdir = "/home/user"; //Remote directory for file upload
   FtpClient ftp = new FtpClient();
   try {
      ftp.openServer(hostname); //Connect to FTP server
      ftp.login(username, password); //Login
      ftp.binary(); //Set to binary mode transfer
      ftp.cd(remdir); //Change to remote directory
      File file = new File(upfile);
      OutputStream out = ftp.put(file.getName()); //Start upload
      InputStream in = new FileInputStream(file);
      byte c[] = new byte[4096];
      int read = 0;
      while ((read = in.read(c)) != -1 ) {
         out.write(c, 0, read);
      } //Upload finished
      in.close();
      out.close();
      ftp.closeServer(); //Close connection
   } catch (Exception e) {
      System.out.println("Error: " + e.getMessage());
   }
 }
}

But it is showing error in Line 11 as 'Cannot instantiate the type FtpClient'. Can some one help me how to rectify it.

回答1:

You cannot instantiate it because sun.net.ftp.FtpClient is abstract class.

I suggest using Apache Commons Net instead of playing with sun.x packages. FTP client example can be found from here.

回答2:

If you do want to use the Sun classes, use FtpClient.create(), as per the JavaDoc for this class.

回答3:

i have resolved the exception.thats because my machine is connected in a network which doesnt allow FTP connection.when i tried it in a private dongle it worked.