public function getRow($field = '*', $where = array(), $order = array(), $offset = 0)
{
// 校验参数
if (!is_string($field) || empty($field)) {
throw new LibraryException('参数错误：$field');
}
if (!is_array($where)) {
throw new LibraryException('参数错误：$where');
}
if (!is_array($order)) {
throw new LibraryException('参数错误：$order');
}
if (!is_numeric($offset) || intval($offset) != $offset || $offset < 0) {
throw new LibraryException('参数错误：$offset');
}
$sql = $this->sqlBuilder->createSelectSql($field, $where, $order, 1, $offset);
$row = $this->slaveHandle->queryRow($sql);
return $row;
}