PHP设计模式之工厂模式与单例模式

val = 20; //clone可以调用__clone()克隆即new出一个新的的对象 //$obj_two = clone $obj_one; $obj_two = instance::getInstance(); echo $obj_two->val; echo '

'; var_dump($obj_one,$obj_two);

int 20 object(instance)[1] public 'val' => int 20

3306,'host' => 'localhost','username' => 'root','passward' => 'root','dbname' => 'instance','charset' => 'utf8' ); private $link; static $instance; private function __clone(){} private function __construct(){ $this->link = mysql_connect($this->arr['host'],$this->arr['username'],$this->arr['passward']) or die(mysql_error()); mysql_select_db($this->arr['dbname']) or die('db error'); mysql_set_charset($this->arr['charset']); } static public function getInsance(){ if(!isset(mysqldb::$instance)){ mysqldb::$instance = new self; } return mysqldb::$instance; } public function query($sql){ if($res = mysql_query($sql)){ return $res; }return false; } //fetch one public function get_one($sql){ $res = $this->query($sql); if($result = mysql_fetch_row($res)){ return $result[0]; } } //fetch row public function get_row($sql){ $res = $this->query($sql); if($result = mysql_fetch_assoc($res)){ return $result; } return false; } //fetch all public function get_all($sql){ $res = $this->query($sql); $arr = array(); while($result = mysql_fetch_assoc($res)){ $arr[] = $result; } return $arr; } } $mysql = mysqldb::getInsance();