<?php//mysql数据库类-mysqli版//2014/6/13class  mysqlidb{     public $dbhost;     public $dbuser;     public $dbpasswd;     public $dbname;     public $dbport;     public $dbobject;     public function __contruct($host,$user,$pwd,$dbname,$port=3306){         $this->dbhost = $host;         $this->dbuser = $user;         $this->dbpasswd = $pwd;         $this->dbname = $dbname;         $this->dbport = $port;                  $this->dbobject = new mysqli($this->dbhost,$this->dbuser,$this->dbpasswd,$this->dbname,$this->dbport);           if ( $this->dbobject -> connect_error ) {         die( ‘Connect Error (‘  .  $this->dbobject -> connect_errno  .  ‘) ‘             .  $this->dbobject -> connect_error );         }     }     public function executesql($sql,$param=array()){         $dbstmt = $this->dbobject->prepare($sql);         if(!empty($param)){           foreach($param as $k => $v){                $dbstmt -> bind_param($k,$v);           }         }         $dbstmt -> execute();         $dbresult = $dbstmt -> get_result();         return  $dbresult->fetch_array();          }}$db = new mysqlidb(‘127.0.0.1‘,‘root‘,‘‘,‘mysql‘);$sql = ‘select * from User‘;$dbrs = $db->executesql($sql);//Fatal error: Call to a member function prepare() on a non-object in C:\xampp\htdocs\tonglei\mysqli\demo2.php on line 28