扩展CodeIgniter系统核心类
首先你系统扩展类是放在application/core下面的，本来系统核心类是CI_Controller，所以你不能以CI_开头了，你需要打开 application/config/config.php 修改 $config['subclass_prefix'] = 'MY_'; 为你的前缀!
一些公共的模块就可以卸载自己的核心类里面了！
这几天读了Dilicms（轻量级的后台架构），比如说他的后台扩展类是这样的：
<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');abstract class Admin_Controller extends CI_Controller{/*** _admin* 保存当前登录用户的信息** @var object* @access public**/public $_admin = NULL;/*** 构造函数** @access public* @return void*/public function __construct(){parent::__construct();$this->load->library('session');$this->settings->load('backend');$this->load->switch_theme(setting('backend_theme'));$this->_check_login();$this->load->library('acl');$this->load->library('plugin_manager');}// ------------------------------------/*** 检查用户是否登录** @access protected* @return void*/protected function _check_login(){if ( ! $this->session->userdata('uid')){redirect(setting('backend_access_point') . '/login');}else{$this->_admin = $this->user_mdl->get_full_user_by_username($this->session->userdata('uid'), 'uid');if ($this->_admin->status != 1){$this->session->set_flashdata('error', "此帐号已被冻结,请联系管理员!");redirect(setting('backend_access_point') . '/login');}}}// ------------------------------------/*** 加载视图** @access protected* @param string* @param array* @return void*/protected function _template($template, $data = array()){$data['tpl'] = $template;$this->load->view('sys_entry', $data);}// ------------------------------------/*** 检查权限** @access protected* @param string* @return void*/protected function _check_permit($action = '', $folder = ''){if ( ! $this->acl->permit($action, $folder)){$this->_message('对不起，你没有访问这里的权限！', '', FALSE);}}// ------------------------------------/*** 信息提示** @access public* @param string* @param string* @param bool* @param string* @return void*/public function _message($msg, $goto = '', $auto = TRUE, $fix = ''){if($goto == ''){$goto = isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : site_url();}else{$goto = strpos($goto, 'http') !== false ? $goto : backend_url($goto);}$goto .= $fix;$this->_template('sys_message', array('msg' => $msg, 'goto' => $goto, 'auto' => $auto));echo $this->output->get_output();exit();}}它就把一些公共信息入验证，登陆，跳转放在Admin_Controller里面，于是我在写前台的时候也是这样操作，扩展了Font_Controller:
abstract class Font_Controller extends CI_Controller{public function __construct() {parent::__construct();}//前台加载视图方法public function _template($template, $data = array()){$data['nav'] = $this->get_nav();$data['tpl'] = $template;$this->load->view('default',$data);}//公共导航信息public function get_nav(){ }//公共友情链接信息public function get_friendlink(){ }}原文参考自站长网：http://www.software8.co/wzjs/PHPshili/3384.html提示,一些经常用到得工具和函数可以放在helper中！
