您好，PHP仍然很陌生，并且正在尝试一些真正的基础知识，这让我感到沮丧，因为我看不到错误。我已经阅读了有关传递对象数组的PHP手册。

class Customer{
    public $companyId;
    public $customerId;
    public $name;

    public function __construct($companyId,$customerId,$name)
    {
       $this->companyId = $companyId;
       $this->customerId = $customerId; 
       $this->name = $name;
    }
}

class CustomersDB
{
...
    /**
     * @return Customer[]
     */
    public function getcustomers($search_str): array {
        $resultObj = array();
        $result = NULL;
        try {
            if (! $this->db) {
                die('Database handle not defined') ;
            } 

            if ($search_str && ! empty($search_str)) {
                $result = $this->ListCustomers(Utils::COMPANY_ID,$search_str,$this->db);
                 while ($row = $result->fetch(PDO::FETCH_ASSOC)) {
                    $_tmp = new Customer($row['CompanyID'],$row['CustomerID'],$row['CustomerName']);
                    // $resultObj.push($_tmp);
                    $resultObj[] = $_tmp;
                }
            }
        } catch (Exception $e) {
            // echo Utils::logMsgtoWeb($e->getTraceAsString());
        } finally {
            $result = NULL;
        }        
        return $resultObj;
    }
}

use Respect\Rest\Routable;
class Customers implements Routable {
    /**
     * 
     * Can pass in a partial string to search for a customer
     * or pass in an ID for a specific match.
     */
    public function get($searchStr){
        // header('Content-type: application/json');
        $result  = $this->custdb.getcustomers($searchStr); // ERRORS HERE

        if ($result && ! empty($result)) {
            return  json_encode( $result);
        } else {
            return NULL;
        }
    }
}

我收到此错误：PHP可恢复的致命错误：Scheduler \ db \ CustomersDB类的对象无法在Customer.php中转换为字符串。 任何帮助将不胜感激。