在PHP登录中使用session

1、之前写的一段登录验证用的代码，现在系统使用了单点登录，所以把自带的权限验证去掉了。版本库中不保留。

    public function loginCheck()
    {
        ob_start();
        $username = $_POST['username'];
        $password = $_POST['password'];
        $data = array();
        $data['path'] = Doo::conf()->APP_URL;
        Doo::loadModel('CdnBsUser',true);
        $cdnBsUser = new CdnBsUser;
        $cdnBsUser = $this->db()->find($cdnBsUser,array('where'=>" username = '$username'"));

        if ( !isset($cdnBsUser[0]->user_id) ) {
            echo "";
            echo "";
            exit();
        }
        $decode_password = md5($password);
        if ( $decode_password != $cdnBsUser[0]->password ) {
            echo "";
            echo "";
            exit;
        } else {
            $_SESSION['login'] = $username;
            header("Location:".$data['path']."index.php/default");
        }
    }

2、注销session并退出登录

    public function logout()
    {
        $data = array();
        $data['path'] = Doo::conf()->APP_URL;
        if ( isset($_SESSION['login'])) {
            session_unregister('login');
            echo "退出登录！";
            $this->view()->render('login',$data);
            exit();
        }
    }

3、一个session验证的类

<?php
/*
 * @File:    nodeController.php
 * @Todo:    Main controller of CDN Billing System.
 * @Author:    yangyi:2011-03-23
 * @Email:    [e-mail]
 */
class sessionCheck
{
    function check(){
        $data['path'] = Doo::conf()->APP_URL;
        if (!isset ($_SESSION['login'])){
            echo "";
            echo "";
            exit();
        }
    }
}
?>

调用类方法：

Doo::loadClass('sessionCheck');
$session = new sessionCheck();
$session->check()