Database Connection Singleton

gistfile1.java

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package org.secondstack.db;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

/**
 *
 * @author Deny Prasetyo
 */
public class DatabaseConnection {

    private static DatabaseConnection instance;
    private Connection connection;
    private String url = "jdbc:postgresql://localhost:5432/jdbc";
    private String username = "root";
    private String password = "localhost";

    private DatabaseConnection() throws SQLException {
        try {
            Class.forName("org.postgresql.Driver");
            this.connection = DriverManager.getConnection(url, username, password);
        } catch (ClassNotFoundException ex) {
            System.out.println("Database Connection Creation Failed : " + ex.getMessage());
        }
    }

    public Connection getConnection() {
        return connection;
    }

    public static DatabaseConnection getInstance() throws SQLException {
        if (instance == null) {
            instance = new DatabaseConnection();
        } else if (instance.getConnection().isClosed()) {
            instance = new DatabaseConnection();
        }

        return instance;
    }
}

But I still have to load the driver through the Maven dependencies.

Using the Class.forName, the postgresql driver will not appear in the project structure.

And how it supposed to work once connection is closed? I don't see how to reopen this connection without restarting the app.

Great!!!

thanks!
But you need a private constructor.

private DatabaseConnection() { }

Calling getInstance will create a new connection if the existing connection is closed.

is there any way not to hardcode URL, username, and password?

Thanks , It really helped me.

you can create an other method public DatabaseConnection createCon(String url, uName, pswrd){}

is there any way not to hardcode URL, username, and password?

So now which method should I call to get the data base connection ?

DBConnection db = DBConnection.getInstance();
Connection conn = db.getConnection();

Thanks, it helped me.