Create Unique File names 3

[Tony220]

Hi,
I Would like my servlet to save a string to a "dump/temp" folder every time it runs. (Backup and debugging purposes)

How do I create a safe file name that is not already there? When using Multipart form upload there is the Default renaming policy that increments the file name if neccessary.
(ie if test.txt already exists this becomes test1.txt if that already exists test2.txt etc..)

Any suggestions?
Thanks a load.

 

[fuadhamidov]

hi

what about time as file name? for example: 19.04.2004 ... .

to how deep you want. hour, minute, second etc.

 

[sedj]

If from a servlet/JSP use :

String filename = request.getSession().getId() +"_" +System.currentTImeMillis() +".txt";

 

[stevexff]

Times can be problematic on a busy system. For example if you are serving three or four hundred transactions per second, especialy on multi-engined CPUs, you can easily get a collision on the file name. sedj's solution is much neater as it uses the session id as well.

 

[Cagliostro]

you can try something like

while(exist(filename)) {filename = basename + next;next++;}
create (filename);
it is a pseudocode, so translate it in java

Ion Filipski

 

[EBGreen]

When using times for filenames, I always recommend:

YYYY-MM-dd-hh-mm-ss

as the format. It makes finding the most recent much simpler.