Java: Connecting to a MySQL Database? DriverManager.getConnection()?

Question

So I was just wondering, what (and probably, how much...) have I done wrong here with this code?

try {
    Class.forName("com.mysql.jdbc.Driver");
    Connection c = DriverManager.getConnection("jdbc:mysql://mysql1.000webhost.com/mydatabase", "myusername", "mypassword");
    } catch (SQLException e) {
        e.printStackTrace();
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
}

As I've triple-checked the username/password, I'm guessing it's something wrong with the host name. The database is only on the server (I don't have any kind of saved local version or anything...do I need to?).

And also, can someone just tell me if I'm on the right lines for what I want to do? Basically I've created a piece of software with a free version and a very cheap paid version. I was thinking that to prevent piracy, since the program requires internet connection anyway, I could store their email address as the username, then their computer's MAC address would be the password (each time the program was run, I would compare the MAC address on their PC with the one registered along with their email in the database. I've got no idea whether that is a good anti-piracy measure, but I was just wondering, if I manage to get the connection working, is that something that I'd be able to do or would there be e.g. security issues with that?

Anyway, thanks in advance :)

Answer 1

if it is not localhost i cannot comment on the host but you also have to give port number.It is missing.

Connection  con = DriverManager
                .getConnection("jdbc:mysql://"+pHost+":"+pPort+"/Your_mysql_schema_name",username, password);

and also in MYSQL your schema name would be your database name.Ensure that you are giving schema name and also port number.Usually for MYSQL its 3306

Answer 2

Writing a piece of java code to operate your database from a remote connection is not a good idea. Someone could reverse engineer your code and change your data.

You should atleast Implement an simple service on the net that could handle the spam you might receive, and protect your data.

Answer 3

I Think you missed the database port no in your URL .Try this :

try {
    Class.forName("com.mysql.jdbc.Driver"); // Not Required for JDBC 4.0 onwards
    Connection c = DriverManager.getConnection("jdbc:mysql://mysql1.000webhost.com: 3306/mydatabase", "myusername", "mypassword");
    } catch (SQLException e) {
        e.printStackTrace();
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }

Answer 4

Try instead of mysql1.000webhost.com to change with server IP address.
Example,

try {
    Class.forName("com.mysql.jdbc.Driver");
    Connection c = DriverManager.getConnection("jdbc:mysql://123.456.789.012:3306/mydatabase", "myusername", "mypassword");
    } catch (SQLException e) {
        e.printStackTrace();
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }

Answer 5

I would recommend you some reading first. This slide show might present you how Java EE applications are build.

Next you might want to read a bit more how to connect your application with a database.

Hibernate is one of the most widely used tools for establishing connection between database and your Java program. It allows you to separate your connection data (e.g. username, password, connection url) from your code with use of configuration files in xml format. The line:

Connection c = DriverManager.getConnection("jdbc:mysql://mysql1.000webhost.com/mydatabase", "myusername", "mypassword");

Is a very dangerous way of establishing connetion, as you are providing confidential credentials inside the code. There are ways to retreive this information from binary files.

You also asked, if is it worth having some local version of your database. The anwser is: Yes. Having your database locally might significantly speed up the time required for development and testing. It also allows you to work on your code even when no internet connection is available.

Providing authentication with use of MAC address is a very dangerous idea. Those addresses are attached to given machines. In other words the user will be able to connect to your application only with machine, on which he or she created an account. When using other computer (e.g. laptop at work) authentication will be denied.