myProject/application/common.php

<?php
// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK ]
// +----------------------------------------------------------------------
// | Copyright (c) 2006-2016 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: 流年 <liu21st@gmail.com>
// +----------------------------------------------------------------------

// 应用公共文件
function mobileAsterisk($mobile)
{
    $mobile_asterisk = substr($mobile,0,4)."****".substr($mobile,8,3);
    return $mobile_asterisk;
}