FTP upload code that returns any error response from the server.

Question

Can someone point me to some java code that can upload a file via FTP. The important thing is that if the FTP responds with an error message I need to obtain it. This is because I need to be sure the file was succesffully uploaded.

I am using the following code, but it does not return an error if the upload fails.

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

/**
 * This class is used to upload a file to a FTP server.
 * 
 * @author Muthu
 */
public class FileUpload
{

   /**
    * Upload a file to a FTP server. A FTP URL is generated with the
    * following syntax:
    * ftp://user:password@host:port/filePath;type=i.
    * 
    * @param ftpServer , FTP server address (optional port ':portNumber').
    * @param user , Optional user name to login.
    * @param password , Optional password for user.
    * @param fileName , Destination file name on FTP server (with optional
    *            preceding relative path, e.g. "myDir/myFile.txt").
    * @param source , Source file to upload.
 * @throws Exception 
    */
   public void upload( String ftpServer, String user, String password,
         String fileName, File source ) throws Exception
   {
      if (ftpServer != null && fileName != null && source != null)
      {
         StringBuffer sb = new StringBuffer( "ftp://" );
         // check for authentication else assume its anonymous access.
         if (user != null && password != null)
         {
            sb.append( user );
            sb.append( ':' );
            sb.append( password );
            sb.append( '@' );
         }
         sb.append( ftpServer );
         sb.append( '/' );
         sb.append( fileName );
         /*
          * type ==> a=ASCII mode, i=image (binary) mode, d= file directory
          * listing
          */
         sb.append( ";type=i" );

         BufferedInputStream bis = null;
         BufferedOutputStream bos = null;
         try
         {
            URL url = new URL( sb.toString() );
            URLConnection urlc = url.openConnection();

            bos = new BufferedOutputStream( urlc.getOutputStream() );
            bis = new BufferedInputStream( new FileInputStream( source ) );

            int i;
            // read byte by byte until end of stream
            while ((i = bis.read()) != -1)
            {
               bos.write( i );
            }
         } catch (Exception e){
             System.out.println("error during file upload");
             throw e;
         }
         finally
         {
            if (bis != null)
               try
               {
                  bis.close();
               }
               catch (IOException ioe)
               {
                  ioe.printStackTrace();
               }
            if (bos != null)
               try
               {
                  bos.close();
               }
               catch (IOException ioe)
               {
                  ioe.printStackTrace();
               }
         }
      }
      else
      {
         System.out.println( "Input not available." );
      }
   }



      /**
        * Download a file from a FTP server. A FTP URL is generated with the
        * following syntax:
        * ftp://user:password@host:port/filePath;type=i.
        * 
        * @param ftpServer , FTP server address (optional port ':portNumber').
        * @param user , Optional user name to login.
        * @param password , Optional password for user.
        * @param fileName , Name of file to download (with optional preceeding
        *            relative path, e.g. one/two/three.txt).
        * @param destination , Destination file to save.
        * @throws MalformedURLException, IOException on error.
        */
       public void download( String ftpServer, String user, String password,
             String fileName, File destination ) throws MalformedURLException,
             IOException
       {
          if (ftpServer != null && fileName != null && destination != null)
          {
             StringBuffer sb = new StringBuffer( "ftp://" );
             // check for authentication else assume its anonymous access.
             if (user != null && password != null)
             {
                sb.append( user );
                sb.append( ':' );
                sb.append( password );
                sb.append( '@' );
             }
             sb.append( ftpServer );
             sb.append( '/' );
             sb.append( fileName );
             /*
              * type ==> a=ASCII mode, i=image (binary) mode, d= file directory
              * listing
              */
             sb.append( ";type=i" );
         BufferedInputStream bis = null;
         BufferedOutputStream bos = null;
         try
         {
            URL url = new URL( sb.toString() );
            URLConnection urlc = url.openConnection();

            bis = new BufferedInputStream( urlc.getInputStream() );
            bos = new BufferedOutputStream( new FileOutputStream(
                  destination.getName() ) );

            int i;
            while ((i = bis.read()) != -1)
            {
               bos.write( i );
            }
         }
         finally
         {
            if (bis != null)
               try
               {
                  bis.close();
               }
               catch (IOException ioe)
               {
                  ioe.printStackTrace();
               }
            if (bos != null)
               try
               {
                  bos.close();
               }
               catch (IOException ioe)
               {
                  ioe.printStackTrace();
               }
         }
      }
      else
      {
         System.out.println( "Input not available" );
      }
   }
}

Any help would be greatly appreciated.

Thanks.

Answer 1

Apache Commons has a Net component that does FTP uploads among other things.

FTPClient is a decent starting point.

Answer 2

Did you read this resource? You maybe can pick something from it. Specifically this page.