public void startConnection() {
		try {
			if ((con == null) || (con.isClosed())) {
				con = DriverManager.getConnection(
						"jdbc:postgresql://java.is.uni-due.de/ws1011",
						"ws1011", "ftpw10");
				System.out.println("Datenbankverbindung hergestellt");
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}