Question

Hello I have this class that contains a actionPerformed to perform a query it looks like this

    MysqlConnect db = new MysqlConnect();

@Override
public void actionPerformed(ActionEvent e) {

    if(e.getSource() == openKnop) {

             try {

                db.connectToAndQueryDatabase("test", "root", "root");
                System.out.println("connection established");

                Statement st = db.createStatement();
                String query = "SELECT id, name, job_id, location FROM person WHERE name = 'Tom Swift'";
                st.executeQuery(query);

                System.out.println("Selected query succesfull");


            } catch (SQLException e1) {
                e1.printStackTrace();
            }
             finally {
                 db.closeCon();
                    System.out.println("connection closed");
             }
    }

and my MysqlConnect(); class looks like this

    public class MysqlConnect{

    protected Connection con;

    public void connectToAndQueryDatabase(String database, String username, String password) throws SQLException {
        con = null;
            try {
                con = DriverManager.getConnection(
                                     "jdbc:mysql://localhost:3306/" + database,
                                     username,
                                     password);
            } catch (SQLException e) {
                e.printStackTrace();
            }
    }

    public void closeCon() {
        con = null;
    }
}

but the problem is at the line

Statement st = db.createStatement();

it doesn’t work like i’ve expected. I’m getting a undefined error.. how can I solve this?

Answer 1

The error says that db an reference of ‘MysqlConnect ‘ doesn’t have createStatement method. you need a Connection object. Make your connectToAndQueryDatabase to return Connection object

 public Connection connectToAndQueryDatabase(String database, String username, String password) throws SQLException {
//your code

return con;
}

and :

Connection conn = db.connectToAndQueryDatabase("test", "root", "root");
                System.out.println("connection established");

                Statement st = conn.createStatement();
                String query = "SELECT id, name, job_id, location FROM person WHERE name = 'Tom Swift'";
                st.executeQuery(query);