PHP单例模式实例,连接数据库对类的引用

<?php//单例模式连接数据库class pzhang{    static private $instance;    private static $config;    private $dbase = array(        ‘host‘ => ‘localhost‘,        ‘username‘ =>‘root‘,        ‘password‘=>‘root‘,        ‘dbname‘ =>‘jmyp‘    );    private function __construct(){    }    static public function getInstance(){         if(!self::$instance instanceof self)             self::$instance  = new self();         return self::$instance;    }    public function conn(){        $mysql_db = $this->dbase[‘dbname‘];        self::$config = new mysqli($this->dbase[‘host‘],$this->dbase[‘username‘],$this->dbase[‘password‘]);        self::$config->query(‘set name utf8‘);        self::$config -> select_db($mysql_db);        $sql = "select * from admin";        $row = self::$config->query($sql);        $data = [];        while($tmp = $row->fetch_assoc()){            $data[] = $tmp;        }        echo "<pre>";        print_r($data);        echo "</pre>";        return self::$config;    }}$obj = pzhang::getInstance();$obj->conn();

//单例模式对类的引用class zhangp{    public function system(){        echo "learning more";    }}

class singleCase{    static private $instance;    private $avg;    private function __construct($config){        self::$instance = new $config;    }    static public function getInstance($avg){        if(!self::$instance instanceof self)             new self($avg);        return self::$instance;    }}$obj = singleCase::getInstance(‘zhangp‘);$obj->system();?>

原文地址：https://www.cnblogs.com/isuansuan/p/9759535.html