格式化时间

format_time.php

public function format_time($create_time)
    {
    	$time = time() - $create_time;

        switch ($time) {
            case $time < 3600:
                $now = ceil($time/60).'分钟前';
                break;

            case $time < 3600*24:
                $now = ceil($time/3600).'小时前';
                break;

            case ($time < 3600*24*30):
                $now = ceil($time/(3600*24)).'天前';
                break;
            
            default:
                $now = date('Y-m-d H:i:s', $create_time);
                break;
        }
        
        return $now;
    }