[FIXED] Moving a database in netbeans to another computer

Issue

I made a fairly small java program in netbeans, with the database saved in the scr folder under database/mainUserData, On my main pc, if i export it to a .jar folder, It works, If i copy all the data in the folder (70mb's worth) to another pc, it can't find the database any more, I made sure to add code that always uses the current directory in the jar folder as a url to the database, this is the connection code:

myconObj = DriverManager.getConnection("jdbc:derby://localhost:1527/MainUserData", "jacovanstryp", "Password1234");

Why is it when i move it to another computer (The whole file, it no longer knows where the database is?

What I have Tried:

URL url = this.getClass().getResource("/com/vanstryp/res/Database/MainUserData"); // This is the same directory as where the .jar is located

This just returns Null.

This is the top Error code it returns

java.sql.SQLNonTransientConnectionException: java.net.ConnectException : Error connecting to server localhost on port 1,527 with message Connection refused: connect.

This is the code for the method I used

  public boolean checkLogin(String username, String password) {
    try {
        Class.forName("org.apache.derby.jdbc.EmbeddedDriver");
        //This code will connect the database to the java program
        //Information to connect database obtained from -->  https://www.youtube.com/watch?v=c7RZV4VLv3s
        Connection myconObj = null; //allows to connect to database
        Statement mystatObj = null; // create statement (Execute queries)
        ResultSet myresObj = null; // get result
        ResultSetMetaData mymeta = null;

        try {

            String query = "select * from JACOVANSTRYP.MAINUSERDATA";
            URL databaseLocation = this.getClass().getResource("/com/vanstryp/database/MainUserData/");

            myconObj = DriverManager.getConnection("jdbc:derby:/" + databaseLocation, "jacovanstryp", "Eduplex1234");
            mystatObj = myconObj.createStatement();
            myresObj = mystatObj.executeQuery(query);
            mymeta = myresObj.getMetaData();
            int colomnNo = mymeta.getColumnCount();

            while (myresObj.next()) {
                String dbUsername = myresObj.getString("Username");
                String dbPassword = myresObj.getString("Password");
                System.out.println();
                if (username.equalsIgnoreCase(dbUsername) && password.equals(dbPassword)) {

                    PrintWriter activeUser = new PrintWriter(new FileWriter("activeUser.db"));
                    activeUser.println(dbUsername);
                    activeUser.close();
                    return true;

                }
            }

        } catch (Exception e) {
            e.printStackTrace();
        }

        return false;
    } catch

 (ClassNotFoundException ex) {
            Logger.getLogger(commonMethods.class.getName()).log(Level.SEVERE, null, ex);
        }
        return false;
}

Solution

This line:

myconObj = DriverManager.getConnection("jdbc:derby://localhost:1527/MainUserData", ...);

uses a connection string of "jdbc:derby://localhost:1527/MainUserData". That means that you have setup (maybe through Netbeans) a Derby server on that computer listening on port 1527.

Copying a jar and the file backing the database is not enough: you must start the Derby server on the new host or use the one from the old host:

myconObj = DriverManager.getConnection("jdbc:derby://other.host.full.name:1527/MainUserData", ...);

---

Alternatively, you could use the embedded mode of Derby. Then you just have to declare which folder contains the database file:

myconObj = DriverManager.getConnection("jdbc:derby:/path/to/MainUserData", ...);

In this mode, you can just copy both the jar (and its optional other files) and the database to the new system, and it should find the database if you give a correct path.

Answered By - Serge Ballesta