getObject method in JDBC should return an Object

[HTHou]

Describe the bug
Currently when using getObject interface in JDBC ResultSet, it will return a String result, which doesn't match the JDBC standard.

See

iotdb/jdbc/src/main/java/org/apache/iotdb/jdbc/AbstractIoTDBJDBCResultSet.java

Lines 436 to 447 in 6eda5e4

	public Object getObject(int columnIndex) throws SQLException {
	try {
	return getObject(ioTDBRpcDataSet.findColumnNameByIndex(columnIndex));
	} catch (StatementExecutionException e) {
	throw new SQLException(e.getMessage());
	}
	}
	@Override
	public Object getObject(String columnName) throws SQLException {
	return getValueByName(columnName);
	}

iotdb/jdbc/src/main/java/org/apache/iotdb/jdbc/IoTDBJDBCResultSet.java

Lines 99 to 105 in 6eda5e4

	protected String getValueByName(String columnName) throws SQLException {
	try {
	return ioTDBRpcDataSet.getValueByName(columnName);
	} catch (StatementExecutionException e) {
	throw new SQLException(e.getMessage());
	}
	}