CODEWITHSUNDEEP
javamysqlapplet
Vipul
Vipul

Reputation: 111

Applet unable to connect to mysql server

I am developing a java applet which connects to mysql database, the applet works fine on local host but when I uploaded it and tried to run, i get an error as "communications link failure the last packet sent successfully to the server was 0 milliseconds ago. the driver has not recieved any packets from the server" i tried it on x10hosting and hostable, please help me if anyone knows the solution...

Upvotes: 0

Views: 873

Answers (2)

T.J. Crowder
T.J. Crowder

Reputation: 1075895

Are you sure your MySQL server port is really open to the public? E.g., on a publicly-routable IP address and not blocked by your routers/network? Most likely your MySQL instance is not accessible from the outside world...

...which is how it should be. It's very, very, very rarely appropriate to have an applet talk directly to your database server. The usual thing is for the applet to talk to a middle tier on your web server, which in turn talks to the database server. There's a security aspect to that (your middle-tier can defend against various attacks on your database), and there's a practicality aspect: You'll probably want to keep the chatter across the public network to a minimum, and your server can roll up the results of multiple operations into one bundle it then sends to the client.

If your MySQL server really is available to the outside world, is its host the same as the host the applet is loaded from? That's one of the security requirements for (unsigned) applets, that they can only open network connections to the same host they were loaded from. But if that were the issue, I would have expected you to get a security exception (unless Connector/J is hiding it from you).

Upvotes: 1

Bozho
Bozho

Reputation: 597432

The applet is client-side. If you want to directly connect to a mysql server this would mean each user that opens the applet should either have mysql installed or have access and credentials to the remote database. Even if your firewall allows the access it is a very bad idea to do so. If you do everyone will have access to your database.

So if you want to communicate with a remote database, use some protocol (http would be easiest, via a Servlet) to send requests to the server and receive responses generated based on the database results. For example invoking http://yoursite.com/addRecord?name=foo&[email protected] could tell the server-side application to open a (local) connection to mysql and insert a record.

Upvotes: 0

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