三种使用php namespace的方法

namespace Christmas\DaysOf;  
class PartridgeInAPearTree{
}

  include 'namespaced-class.php';
$bird1 = new Christmas\DaysOf\PartridgeInAPearTree();
var_dump($bird1);

  include 'namespaced-class.php';
use Christmas\DaysOf;
$bird2 = new DaysOf\PartridgeInAPearTree();
var_dump($bird2);

 include 'namespaced-class.php';
use Christmas\DaysOf\PartridgeInAPearTree as Bird;            
$bird3 = new Bird();
var_dump($bird3);