Question

php连接数据库失败

<?phpclass Db{ static private $_instance; static private $_connectSource; private $_dbConfig = array( 'host' => '127.0.0.1', 'user' => 'root', 'password' => '', 'database' => 'stage', ); private function __construct(){ } static public function getInstance(){ if(self::$_instance instanceof self){ self::$_instance = new self(); } return self::$_instance; } public function connect(){ if(!self::$_connectSource){ self::$_connectSource = mysql_connect($this->_dbConfig['host'],$this->_dbConfig['user'],$this->_dbConfig['password']); if(!self::$_connectSource){ die('mysql connect error'.mysql_error()); } mysql_select_db($this->_dbConfig['database'],self::$_connectSource); mysql_query("set names UTF8",self::$_connectSource); } return self::$_connectSource; }}$connect = Db::getInstance()->connect();$sql = "select * from stage";$result = mysql_query($sql,$connect);var_dump($result);这是我的php文件，然后我试着运行，但是返回错误Fatal error: Uncaught Error: Call to a member function connect() on null in /Applications/XAMPP/xamppfiles/htdocs/connect.php:37 Stack trace: #0 {main} thrown in /Applications/XAMPP/xamppfiles/htdocs/connect.php on line 37数据库已开启可以正常访问

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Answer 1

mysql_connect();
你先用php文件调用这个填上你的信息参数
看看连接成不成功，然后看下mysql_error 出来什么

追问

我单独写PHP文件调用信息参数可以连接，返回的是正常的，但是通过这种单例的方式不知道为什么就不行