PHP面向对象魔术方法之__get 和 __set函数

<?php ???header(‘content-type:text/html;charset=utf-8‘); ???//__get 和 __set ???class Monkey{ ???????public $name; ???????protected $food; ???????public function __construct($name, $food){ ???????????$this->name = $name; ???????????$this->food = $food; ???????} ???????//魔术方法 __get ???????//1. 魔术方法名字是固定，系统提供 ???????//2. $pro_name 是形式参数，表示属性名 ???????public function __get($pro_name){ ???????// ???????????echo ‘<br> pro_name ‘ . $pro_name; ???????????????????????//做一个判断
 ???????????if(property_exists($this, $pro_name)){ ???????????????return $this->$pro_name; ???????????}else{ ???????????????return ‘没有该属性，无法返回!‘; ???????????} ???????} ???????//魔术方法 __set ???????//1. 魔术方法名字是固定，系统提供 ???????//2. $pro_name 是形式参数，表示属性名, $pro_val 是属性值 ???????public function __set($pro_name, $pro_val){ ???????????????????//echo ‘<br> $pro_name = ‘ . $pro_name . ‘ pro_val ‘ . $pro_val; ???????????//判断属性是否存在 ???????????if(property_exists($this, $pro_name)){ ???????????????$this->$pro_name = $pro_val; ???????????}else{ ???????????????return ‘属性不存在，无法赋值‘; ???????????} ???????} ???} ???//创建对象 ???$monkey1 = new Monkey(‘妖猴‘, ‘小孩‘); ???echo ‘<br> 猴子名字是 ‘ . $monkey1->name; ???//需求 ???//因为 food是不可访问的属性(protected) ???echo ‘<br> 猴子喜欢吃 ‘ . $monkey1->food; ???//修改猴子的名字和食物 ???$monkey1->name = ‘猴妖‘; ???//在默认情况下，不能直接给一个protected属性赋值, 会触发 ???//__set魔术方法. ???$monkey1->food = ‘桃子‘; ???echo ‘<br> 新的值是 <br>‘; ???echo ‘<br> 猴子名字是 ‘ . $monkey1->name; ???//需求: ???echo ‘<br> 猴子喜欢吃 ‘ . $monkey1->food;