private static $_instance; private function __construct() { } private static function get_instance() { if(!isset(self::$_instance)){ self::$_instance = new self(); }else{ return self::$_instance; } } //阻止clone private function __clone() { trigger_error('Clone is not allow', E_USER_ERROR); } function test() { echo "test"; } } $test = man::get_instance(); $test->test(); ?>