PHP单例模式

<?php

class OA {

    public static $oa = array();
    public static $config = array();

    public static function setConfig(array $config) {
        return self::$config = array_merge(self::$config, $config);
    }

    public static function user() {
        oa_import("user");
        if (!key_exists(‘user‘, self::$oa) || !is_object(self::$oa[‘user‘])) {
            self::$oa[‘user‘] = new user();
        }
        return self::$oa[‘user‘];
    }

}

<?php
　　OA::setconfig($config);
　　OA::user()->get();
?>