Dedicated server: why can't my JAVA application connect to my MySQL database?

Question

I got a dedicated server under Debian (amd64).

I installed a MySQL database with phpmyadmin and a Tomcat 6 server to deploy the JAVA application I just developed.

When I run this application once deployed, an exception is thrown: org.hibernate.exception.GenericJDBCException: Cannot open connection

I thought maybe my database credentials were wrong, so I wrote a little PHP script that I put on my remote Apache2 server, to see if it can connect to the same database, and yes: it can.

This is my PHP script:

$link = mysql_connect('localhost', 'mylogin', 'mypassword');
mysql_select_db('mydatabase', $link);
$query = mysql_query('SELECT * FROM source');
$result = mysql_fetch_array($query);
var_dump($result);

The output is the list of the entries within my source table, alright. So why does my JAVA application can't connect to that #@!?€ database?

This is my pom.xml :

<jdbc.type>mysql</jdbc.type>
<jdbc.driver>com.mysql.jdbc.Driver</jdbc.driver>
<jdbc.url>jdbc:mysql://localhost/mydatabase</jdbc.url>
<jdbc.user>mylogin</jdbc.user>
<jdbc.password>mypassword</jdbc.password>
<hibernate.dialect>org.hibernate.dialect.MySQLInnoDBDialect</hibernate.dialect>

I also tried with

<jdbc.url>jdbc:mysql://localhost:3306/mydatabase</jdbc.url>

and

<jdbc.url>jdbc:mysql://012.345.678.9:3306/mydatabase</jdbc.url>

but it still doesn't work...

PS1: it works like a charm on a local server on my own machine.

PS2: everything is on the same remote machine (ie MySQL, Tomcat and Apache).

PS3: I bought the dedicated server to Online (maybe a bit too french for some of you...).

PS4: don't hesitate to ask me more details, I dunno what could be usefull to you to help me solving that problem...

Answer 1

I guess you have missed the port in the <jdbc.url> .

You might modify the url from <jdbc.url>jdbc:mysql://localhost/mydatabase</jdbc.url> to <jdbc.url>jdbc:mysql://localhost:port/mydatabase</jdbc.url> .

The port mostly is 3306 .

You could put in the ip of the MySQL server instead of localhost with the port and I think it should work.

Answer 2

There might be firewall rules in place. Quite common on server installations.

Check if you can telnet to the mysql port. If not, talk to the system administrator.

Answer 3

I finally deployed it using mvn tomcat:deploy , and it worked. I was uploading the WAR file via the manager/html interface of Tomcat before.