resume/reconnection problem

Question

Hi,

I'm using edtftpj free version in my java project.

there is an issue we want to sort out.
suppose the following senario :

files are being uploaded to a ftp server (in a separate java thread).then user brutally unplug the lan cable and cutt of network connection...
after few secs user plug the cable again .
Now we need to be able to resume uploading files from point where the network connection went down.

what i did is the following :

i catch exception that is throw when connection is broken ,then i call :

client.resume();

but this doesn't work ,many exceptions are thrown.the exception trace is below.

can someone pint me how to come out right with this issue?

thanks a lot.

DEBUG [FTPControlSocket] 5 Jul 2007 09:25:59.409 : 226 Transfer finished successfully. Data connection closed.
DEBUG [FTPControlSocket] 5 Jul 2007 09:25:59.409 : ---> CWD /staging/Projects/12/View/_Thumbs
DEBUG [FTPControlSocket] 5 Jul 2007 09:25:59.471 : 250-[Ul: 58.61MB] [Dl: 0.00MB] [Speed: UL:45,DL:0 KB/s] [Space: 355042MB]
DEBUG [FTPControlSocket] 5 Jul 2007 09:25:59.471 : 250-[Credits: UnlimitedMB] [Ratio: Unlimited]
java.net.SocketException: Connection reset
   at java.net.SocketInputStream.read(Unknown Source)
   at sun.nio.cs.StreamDecoder$CharsetSD.readBytes(Unknown Source)
   at sun.nio.cs.StreamDecoder$CharsetSD.implRead(Unknown Source)
   at sun.nio.cs.StreamDecoder.read(Unknown Source)
   at java.io.InputStreamReader.read(Unknown Source)
   at java.io.BufferedReader.fill(Unknown Source)
   at java.io.BufferedReader.readLine(Unknown Source)
   at java.io.BufferedReader.readLine(Unknown Source)
   at com.enterprisedt.net.ftp.FTPControlSocket.readReply(FTPControlSocket.java:825)DEBUG [upload.FTPUploadThread] 5 Jul 2007 09:26:08.612 : Error processing thumbnails 'A-group005.jpg'at 

Answer 1

thanks a mil

what is the method to call on FTPClient to disconnect ?

thanks.

Answer 2

FTPClient.quit()

- Hans (EnterpriseDT)

Answer 3

sorry ,i'm still having issues with this resume/reconnection problem.

is there another robust approach to monitor when the connection is down and notify my applet so it retry to reconnect & resume ?

the exception thrown approach seems not to be good.

can i for example launch a thread for monitoring connection status & if the thread discovers the connection is down ,it then try to reconnect & resume.

i would appreciate some source code from your part to help on this.

thanks.

Answer 4

The problem is when a connection is down you don't know when it will come up again. All you can do is quit, call sleep, retry connection in a loop.

Instead of quit(), call quitImmediately() (but catch any exceptions) - that will help. Then sleep & try reconnecting.