问Java -I无法查看预设mysql数据库中的表，但可以查看用户创建的数据库中的表

EN

public static Connection getConnection(Database database) throws SQLException {
        try {
            Class.forName(database.getDriver()).newInstance();

            Properties property = new Properties();
            property.setProperty("user", database.getUser().getUsername());
            property.setProperty("password", database.getUser().getPassword());

            connection = DriverManager.getConnection(database.getUrl(), property);

        } catch (SQLException | InstantiationException | IllegalAccessException ClassNotFoundException ex) {
            ex.printStackTrace();
        }
        return connection;
    }

DefaultMutableTreeNode root = new DefaultMutableTreeNode("Databases");

        JTree tree = new JTree(root);

        DefaultTreeModel model = (DefaultTreeModel) tree.getModel();

        try {
            DatabaseMetaData databaseMetaData = getDatabaseMetaData(database);

            ResultSet resultSet = databaseMetaData.getCatalogs();

            while (resultSet.next()) {
            DefaultMutableTreeNode db = new DefaultMutableTreeNode(resultSet.getString("TABLE_CAT"));
            root.add(db);
            getDatabaseTableTree(database, tree, db);
        }
    } catch (SQLException ex) {
        ex.printStackTrace();
    } catch (Exception ex) {
        ex.printStackTrace();
    }

public static DatabaseMetaData getDatabaseMetaData(Database database) throws SQLException {
        return getConnection(database).getMetaData();
}

private String driver = "com.mysql.jdbc.Driver";
private String databaseName = "";
private String url = "jdbc:mysql://localhost:3306/";
private User user = null;
private String tableName = "";