Guys i wanted to connect Java Application with MySql database.I have written a Java Programme.I have already created the database also.But it doesn't connect with the Database.This is my code.

import java.sql.*;

   public class check
   {
       public static void main (String[] args)
       {
           Connection conn = null;

           try
           {
               String userName = "root";
               String password = "sss";
               String url = "jdbc:mysql://localhost/musicdb";
               Class.forName ("com.mysql.jdbc.Driver").newInstance ();
               conn = DriverManager.getConnection (url, userName, password);
               System.out.println ("Database connection established");
               //Connection connection=getConnection();
               Statement st=null;
               ResultSet rs=null;
                st=conn.createStatement();
                rs=st.executeQuery("select count(*) from musicdata");
                rs.next();
                int musicCount=rs.getInt(1);
                System.out.println("Music Count:"+musicCount);
           }
           catch (Exception e)
           {
               System.err.println ("Cannot connect to database server");
           }
           finally
           {
               if (conn != null)
               {
                   try
                   {
                       conn.close ();
                       System.out.println ("Database connection terminated");
                   }
                   catch (Exception e) { /* ignore close errors */ }
               }
           }
       }
}

Is this correct?

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All 10 Replies

Are you getting any errors?.. If so post them ..

No,it just prints "Cannot connect to database server"....

That is because you are pretty much ignoring the exception it throws (line 28 and line 39) which is a bad thing. Never catch exceptions only to replace them with "print" statements or worst, with an empty catch block. Till you incorporate a logger in your application (which IMO every non-trivial application should have), your best bet would be to dump the entire stack trace at the time the exception was thrown.

Do a 'e.printStackTrace()' of the exception and post the entire exception text here.

commented: Who need to listen for exceptions, their are pointless ;) +16

@pro learner. As SOS suggested you need to put e.printStackTrace() in your code and its good to make it as habit whenever you write the code.

And i think you should specify the port number of your mysql in line 13.

The default port number of mysql is 3306.So assuming that you dint change the post number manually , it should be as follows

String url = "jdbc:mysql://localhost:3306/musicdb";

Declare database too:

String db = "yourdatabase";

and add database like seen here:

conn = DriverManager.getConnection (url + db, userName, password);

Also, add port number and

e.printStackTrace()

as mentioned above.

Declare database too:

String db = "yourdatabase";

and add database like seen here:

conn = DriverManager.getConnection (url + db, userName, password);

Also, add port number and

e.printStackTrace()

as mentioned above.

I guess he already added the database name.

String url = "jdbc:mysql://localhost/musicdb";

musicdb is database name.

Yes,i have already declared the DB.And before this code,i tried e.printStackTrace() one.But it also didn't worked.That was why i moved to this way.

How did printStackTrace "not work". You need to explain that one more. In any case, add a printStackTrace anyway and post the results of that.

Anyway finally it solved by my own....:):)

Anyway finally it solved by my own

Oh. that's great..!:) If possible , post what went wrong and what did you do to solve so that others who encounter the same problem will be benifited.

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