'查询',2=>'添加',4=>'修改',8=>'删除');              /**      *      */      public function __set($name,$value)        {           if ($name == 'usertype')            {               if ($value != '')                {                   $this->usertype = $value;                }            }        }              /**      * 构造函数 给角色赋予权限      */      private function __construct()        {           $this->annoy = self::SELECT;           $this->user = self::SELECT | self::CREATE;           $this->admin = self::SELECT | self::CREATE | self::EDIT | self::DELETE;        }              /**      * 获取类的唯一实例      */      public static function getInstance()        {           if (self::$instance === null){                self::$instance = new include_purview();            }           return self::$instance;        }              /**      * 检查权限      *      * @param $usertype 角色      * @param $purview 权限      */      public function check($purview)        {           if ($this->{
   $this->usertype} & $purview)            {               return true;            }           return false;        }              /**      * 给角色加权限      */      public function addPur($purview)        {           $this->{
   $this->usertype} |= $purview;        }              /**      * 给角色减权限      */      public function delPur($purview)        {           $this->{
   $this->usertype} ^= $purview;        }              /**      * 返回角色拥有的权限      */      public function getPur()        {           $arr = array();           foreach ($this->hashtable as $k => $v)            {               if ($k & $this->{
   $this->usertype})                {                   $arr[] = $v;                }            }           return $arr;        }   }  调用示例PHP代码/*** 示例*/  //在session中读用户组   @session_start();   $_SESSION['role'] = 'user';     //获取权限类的实例   $pruview = include_purview::getInstance();   //设置角色   $pruview->usertype = $_SESSION['role'];   //获取该角色拥有的权限   $arr = $pruview->getpur();   echo '该用户的权限有:'.join(',',$arr)."\n";   //判断执行的操作是否有权限   if (true === $pruview->check(include_purview::CREATE ))   {        create(); //要执行的操作   }   else   {       exit('您没有权限!');   }   //去掉用户的添加权限   $pruview->delPur(include_purview::CREATE );   $arr = $pruview->getpur();   echo '该用户的权限有:'.join(',',$arr)."\n";   //执行添加操作   if (true === $pruview->check(include_purview::CREATE ))   {        create(); //要执行的操作   }   else   {       echo '您没有权限!'."\n";   }   //加上用户的添加权限   $pruview->addPur(include_purview::CREATE );   $arr = $pruview->getpur();   echo '该用户的权限有:'.join(',',$arr)."\n";   //执行添加操作   if (true === $pruview->check(include_purview::CREATE ))   {        create(); //要执行的操作   }   else   {       exit('您没有权限!');   }     //具体的操作   function create()   {       echo '执行了添加操作'."\n";   }