### Question:
DbManager { public ResultSetMetaData getResultSetMetaData(ResultSet resultSet) { try { return resultSet.getMetaData(); } catch (SQLException e) { throw new RuntimeException("get ResultSetMetaData exception : " + e.getMessage(), e); } } DbManager();  DbManager(String url, String user, String password); Connection getConnection(); PreparedStatement getPreparedStatement(Connection connection, String sql); ResultSet getResultSet(PreparedStatement preparedStatement); ResultSet getTables(Connection connection, String localCatalog, String localSchema, String localTableName); ResultSet getColumns(Connection connection, String localCatalog, String localSchema, String localTableName); ResultSet getPrimaryKeys(Connection connection, String localCatalog,
									String localSchema, String localTableName); ResultSetMetaData getResultSetMetaData(ResultSet resultSet); DatabaseMetaData getDatabaseMetaData(Connection connection); void close(Connection connection, PreparedStatement preparedStatement, ResultSet resultSet); void close(Connection connection); void close(PreparedStatement preparedStatement); void close(ResultSet resultSet); String getDriveName(); void setDriveName(String driveName); String getUrl(); void setUrl(String url); String getUser(); void setUser(String user); String getPassword(); void setPassword(String password);  }### Answer:
@Test public void testGetResultSetMetaData() throws Exception { Connection connection = dbManager.getConnection(); PreparedStatement preparedStatement = dbManager.getPreparedStatement(connection, "select count(1) as count from tb_user"); ResultSet resultSet = dbManager.getResultSet(preparedStatement); ResultSetMetaData resultSetMetaData = dbManager.getResultSetMetaData(resultSet); assertNotNull(resultSetMetaData); assertEquals(resultSetMetaData.getColumnCount(), 1); }