PHP消息：PHP注意：未定義變量：conn

Question

我已經將PHP版本從5切換到7，並且在連接到數據庫期間發生以下錯誤。

FastCGI的在標準錯誤發送：「PHP消息：通知PHP：未定義變量：CONN在/www/admin/Connection.php線14上

1. 從命令行到數據庫的連接是OK 。

2. 連接，從標準的PHP代碼數據庫確定爲好。

   <?php 
   class Connection 
   { 
   private static $conn; 
   private $dbHost; 
   private $dbUser; 
   private $dbPass; 
   private $dbName; 
   public $dbHandle; 
   public $languages; 
   
   public static function getConnection() 
   { 
        if($conn == null) 
          self::$conn = new Connection(); 
        return self::$conn; 
   } 
   
   protected function __construct() 
   { 
        $this->dbhost = BV_DB_HOST; 
        $this->dbuser = BV_DB_USER; 
        $this->dbpass = BV_DB_PASS; 
        $this->dbname = BV_DB_NAME; 
        $this->dbConnect(); 
   } 
   
   public function dbConnect() 
   { 
        $this->dbHandle = mysqli_connect(BV_DB_HOST, BV_DB_USER, BV_DB_PASS); 
        $tmp = mysqli_select_db($this->dbHandle, BV_DB_NAME); 
        mysqli_query($this->dbHandle, "set names utf8"); 
        return $tmp; 
   } 
   
   public function languages() 
   { 
        return explode(";", BV_LANGS); 
   } 
   } 
   ?> 
   

我該如何解決該問題？

Answer 1

我在getConnection（）中的IF語句中更改了條件，如下所示。

if(!isset($conn))