thinkphp中类似java过滤器的实现

写java web代码的时候，可以定义过滤器，对控制器进行过滤，可以实现权限验证等等

在thinkphp中也可以通过继承父类的方法，实现类似的需求

父类代码

<?php
/**
 * Created by PhpStorm.
 * User: xieyicheng
 * Date: 2014/12/11
 * Time: 14:43
 */
namespace AdminController;
use ThinkController;

class CommonController extends Controller
{
    public function _initialize()
    {
        if(!isset($_SESSION["username"])) {
            redirect( U("Admin/Login/index"), 0);//没登陆，跳转到登陆页
        }
    }
}

<?php
/**
 * Created by PhpStorm.
 * User: xieyicheng
 * Date: 2014/12/4
 * Time: 13:06
 */

namespace AdminController;
use HomeModel;
use  AdminModelShop;

class FileController extends CommonController
{
    public function index()
    {
        $this->display();
    }
}