Thread: How to improve FTP upload speed for multiple files.

I implemented java code to upload files to server with org.apache.commons.net.ftp.FTPClient (commons-net-3.3.jar).

Following is example code:

// create instance of FTPClient
FTPClient ftp = new FTPClient();
 
ftp.setControlEncoding("UTF-8");
ftp.setDefaultTimeout(30000);
 
 
// connect to server
try
{
    ftp.connect("10.1.1.1", 21);
}
catch(Exception e)
{
    System.out.println("Cannot connect to server");
    return;
}
 
// login to server
if (!ftp.login("username", "password"))
    {
        ftp.logout();
        System.out.println("Cannot login to server");
        return;
    }
 
try
{
	ftp.setFileType(FTP.BINARY_FILE_TYPE, FTP.BINARY_FILE_TYPE);
	ftp.setFileTransferMode(FTP.BINARY_FILE_TYPE);
	ftp.enterLocalPassiveMode();
}
catch(Exception e)
{
}
// create directory on server
// dirs is list of required directories on server
for (String dir : dirs)
    {
        try
        {
            ftp.makeDirectory(dir);
        }
        catch(IOException e)
        {
        }
    }
 
 
// files is a map of local file and string of remote file
// such as 
// file on client is "C://test/a.txt"
// location on server is "/test/a.txt"
for (Map.Entry<File, String> entry : files.entrySet())
    {
        File localFile = entry.getKey();
        String remoteFile = entry.getValue();
 
        InputStream input = null;
        try
        {
            input= new FileInputStream(localFile);
            ftp.storeFile(remoteFile, input);
        }
        catch (Exception e)
        {
            try
            {
                ftp.deleteFile(remoteFile);
            }
            catch (IOException e1)
            {
            }
        }
        finally
        {
            if (input != null)
            {
                try
                {
                    input.close();
                }
                catch (IOException e)
                {
                }
            }
        }
    }
 
// disconnect
if (ftp != null && ftp.isConnected())
    {
        try
        {
            ftp.disconnect();
        }
        catch (IOException f)
        {
            // do nothing
        }
    }

I try to upload 100 files (each file is about 2-10 KB). It took about 174375 - 210203 millisec. I would like to improve the speed.

How should I do?

- Change library? What is the powerful FTP client class library for uploading multiple files (only open source or free library)?

- Use multiple threads? How can I implement ftp upload function with multiple threads? Could someone show me an example? I am a new for multiple threading programming.

I try to use this code for multiple threads:

final CountDownLatch latch = new CountDownLatch(files.size());
ExecutorService pool = Executors.newFixedThreadPool(5);
final org.apache.commons.net.ftp.FTPClient client = ftp;
for (Map.Entry<File, String> entry : files.entrySet())
{
	final File localFile = entry.getKey();
	final String remoteFile = entry.getValue();
 
	pool.execute(new Runnable() {
		public void run()
		{
			try
			{
				uploadFile(client, localFile, remoteFile);
			}
			catch (Exception e)
			{
 
			}
			finally
			{
				latch.countDown();
			}
		}
	});
}
try
{
	// waiting for all threads finish
	latch.await();
}
catch (Exception e)
{
 
}

uploadFile method:

private void uploadFile(org.apache.commons.net.ftp.FTPClient ftp, File payLoad, String remoteLoc)
{
	InputStream input = null;
	try
	{
		input = new FileInputStream(payLoad);
		ftp.storeFile(remoteLoc, input);
	}
	catch (Exception e)
	{
		try
		{
			ftp.deleteFile(remoteLoc);
		}
		catch (Exception e1)
		{
		}
		e.printStackTrace();
	}
	finally
	{
 
		if (input != null)
			try
			{
				input.close();
			}
			catch (Exception e)
			{
			}
	}
}

Is it correct?

Can anyone help me?

Thanks in advance
Darknight