/**    * 利用php的序列化和反序列化来做简单的数据本地存储    */    class objectdb    {                private static $db;        //成功返回 objectdb 对象,不需要在外面使用new        //目录需要写文件的权限        public function defaultdb($dbname=‘./default.db‘)        {            self::$db = $dbname;            if(file_exists($dbname))            {                    return new objectdb();            }               $ret=file_put_contents($dbname,serialize(array()));               if ($ret > 0) {                    return new objectdb();               }                return false;        }        //添加数据key,value 或更新        public function setValueForKey($key,$value)        {            $arrdata = $this->getDBarray();            $arrdata[$key] = $value;            return $this->setDBarray($arrdata);        }        //删除指定key的数据        public function removeValueForKey($key)        {            $arrdata = $this->getDBarray();            unset($arr[$key]);        }        //获取指定key的数据        public function getValueForKey($key)        {            $arrdata = $this->getDBarray();            return $arrdata[$key];        }        //获取所有的数据        public function getAll()        {            $arrdata = $this->getDBarray();            return $arrdata;        }        //获取所有的key        public function getAllKey()        {            $arrdata = $this->getDBarray();            return array_keys($arrdata);        }        //清空db数据        public function cleardb()        {            $ret=file_put_contents(self::$db,serialize(array()));            return $ret;        }        //private get        private function getDBarray()        {            $rdata=file_get_contents(self::$db);             return unserialize($rdata);        }        //private set        private function setDBarray($arr)        {            $ret=file_put_contents(self::$db,serialize($arr));             if ($ret > 0) {                return true;            }else            {                return false;            }        }    }    

    //test    $dbhandle = objectdb::defaultdb();    if (!$dbhandle) {        echo "init failure!";        exit();    }    echo "start <br>";    var_dump($dbhandle->getAll());    echo "<br>add 1 <br>";    $dbhandle->setValueForKey("baidu","www.baidu.com");    $dbhandle->setValueForKey("qq","www.qq.com");    $dbhandle->setValueForKey("taobao","www.taobao.com");    var_dump($dbhandle->getAll());    echo "<br>mod 1 <br>";    $dbhandle->setValueForKey("baidu","http://www.baidu.com");    var_dump($dbhandle->getAll());    echo "<br>get 1 <br>";    echo $dbhandle->getValueForKey("baidu");        echo "<br>get 1 <br>";    var_dump($dbhandle->getAllKey());    echo "<br>clear 1 <br>";    $dbhandle->cleardb();    echo "<br>get 1 <br>";    var_dump($dbhandle->getAll());