which is the best way to update an application from a server?

I'm looking for a non-webstart/jnlp solution.

I'd like to add to my app an update feature that checks in an ftp or http server and downloads the last version (if there is a newer one) replacing the libs that has been changed.

How can i do th开发者_StackOverflow中文版at? I want to implement something like JDownloaders updates.

Thanks

It looks like you just described exactly how to do it. Add an update feature that checks an FTP or HTTP server and downloads the latest version.

Remember that you cannot download and overwrite a file which is in use. So you have two options for a design from where I sit:

1. When you start up the application, copy all of the jar and library files to a /temp folder of some sort before running them. Then, when you download the update, overwrite the files in the original place. The next time the application starts up, it will use the new files.

2. When you start up the application, first startup an updater. Have it connect to the server and compare all of the file versions. It will be able to overwrite any of the application files because it doesn't use them. It only uses the updater jar. Once this is done and everything has been updated, then start a new process from the updater with the actual application. You will also need to put some code in to be able to update the updater jar. Either make the main application be able to update the updater, or use the first technique and run the updater from a copy of the updater jar.

Remember when you download the files that you should be downloading them to a temporary location and then moving them to the right place when they're done. This will make sure that you never leave your application in a "half-downloaded" state.

Beyond that, getting this to work is going to be about a lot of testing. Good luck!

Have a look at http://code.google.com/p/getdown/

According to this question on stackoverflow it seem to be a viable alternative for web start (at least worth having a look at).