MySQL-Klasse

package de.comniemeer.mysqlbeispiel;

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

    private Main plugin;

    private Connection conn;

    public MySQL(Main main) throws Exception {
        this.plugin = main;

        FileConfiguration cfg = this.plugin.getConfig();
        String db = "MySQL.";

        this.host = cfg.getString(db + "Host");
        this.port = cfg.getInt(db + "Port");
        this.user = cfg.getString(db + "User");
        this.password = cfg.getString(db + "Passwort");
        this.database = cfg.getString(db + "Datenbank");

        this.openConnection();
    }

    public Connection openConnection() throws Exception {
        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;
    }

    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) {
            this.plugin.log.severe("Failed to send update '" + query + "'.");
        } 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;
        }
    }
}