二级域名设置解析方法

w服务商解决域名指向哪个服务器ip，之后请求服务器时，脚本对二级域名进行路由控制，访问指定脚本。

https://help.aliyun.com/knowledge_detail/39785.html

http://codeigniter.org.cn/forums/thread-16699-1-1.html

1-在域名服务商添加A记录指向同ＩＰ；

2-CI \application\config\routes.php

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

/*
| -------------------------------------------------------------------------
| URI ROUTING
| -------------------------------------------------------------------------
| This file lets you re-map URI requests to specific controller functions.
|
| Typically there is a one-to-one relationship between a URL string
| and its corresponding controller class/method. The segments in a
| URL normally follow this pattern:
|
|    example.com/class/method/id/
|
| In some instances, however, you may want to remap this relationship
| so that a different class/function is called than the one
| corresponding to the URL.
|
| Please see the user guide for complete details:
|
|    https://codeigniter.com/user_guide/general/routing.html
|
| -------------------------------------------------------------------------
| RESERVED ROUTES
| -------------------------------------------------------------------------
|
| There are three reserved routes:
|
|    $route['default_controller'] = 'welcome';
|
| This route indicates which controller class should be loaded if the
| URI contains no data. In the above example, the "welcome" class
| would be loaded.
|
|    $route['404_override'] = 'errors/page_missing';
|
| This route will tell the Router which controller/method to use if those
| provided in the URL cannot be matched to a valid route.
|
|    $route['translate_uri_dashes'] = FALSE;
|
| This is not exactly a route, but allows you to automatically route
| controller and method names that contain dashes. '-' isn't a valid
| class or method name character, so it requires translation.
| When you set this option to TRUE, it will replace ALL dashes in the
| controller and method URI segments.
|
| Examples:    my-controller/index    -> my_controller/index
|        my-controller/my-method    -> my_controller/my_method
*/

//$route['default_controller'] = 'welcome';

switch($_SERVER['HTTP_HOST']){
    case 'admin.w.cn':
        $route['default_controller']='ww';
        $route['view/(:any)'] = 'ww/view/$1';
        break;
    default:
        $route['default_controller'] = 'blog';
        break;
}


$route['404_override'] = '';
$route['translate_uri_dashes'] = FALSE;