Spigot 1.9+ MySQL API

package de.cynfos.mysqlapi;

import java.io.File;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import org.bukkit.configuration.file.FileConfiguration;

public class MySQL {

    private int port;
    private String host, user, password, database;

    private Connection conn;

    public MySQL() {
        File file = new File("plugins/MySQL-API/", "config.yml");
        FileConfiguration cfg = this.plugin.getConfig();

        String db = "database.";

        cfg.addDefault(db + "host", "localhost");
        cfg.addDefault(db + "port", 3306);
        cfg.addDefault(db + "user", "root");
        cfg.addDefault(db + "password", "password");
        cfg.addDefault(db + "database", "database");

        cfg.options().copyDefaults(true);

        try {
            cfg.save(file);
        } catch (IOException e) {
            e.printStackTrace();
        }

        this.host = cfg.getString(db + "host");
        this.port = cfg.getInt(db + "port");
        this.user = cfg.getString(db + "user");
        this.password = cfg.getString(db + "password");
        this.database = cfg.getString(db + "database");

        this.openConnection();
    }

    private Connection openConnection() {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            Connection conn = DriverManager.getConnection("jdbc:mysql://" + this.host + ":" + this.port + "/" + this.database, this.user, this.password);
            this.conn = conn;

            return conn;
        } catch (SQLException | ClassNotFoundException e) {
            e.printStackTrace();
        }

        return null;
    }

    public Connection getConnection() {
        return this.conn;
    }

    public boolean hasConnection() {
        try {
            return this.conn != null || this.conn.isValid(1);
        } catch (SQLException e) {
            return false;
        }
    }

    public void queryUpdate(String query) {
        Connection conn = this.conn;
        PreparedStatement st = null;

        try {
            st = conn.prepareStatement(query);
            st.executeUpdate();
        } catch (SQLException e) {
            System.err.println("[MySQL] Failed to send update '" + query + "' (" + e.getMessage() + ")");
        } finally {
            this.closeRessources(null, st);
        }
    }

    public void closeRessources(ResultSet rs, PreparedStatement st) {
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
            }
        }

        if (st != null) {
            try {
                st.close();
            } catch (SQLException e) {
            }

        }
    }

    public void closeConnection() {
        try {
            this.conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            this.conn = null;
        }
    }

}