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;
    }
}

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.