php魔术方法

Posted 2021-02-16 农夫有鸡

1. __construct  构造方法

    1 class Person
    2 {
    3     public $name;
    4 
    5     # 构造方法
    6     public function __construct($n){
    7         $this->name = $n;
    8     }
    9 
   10     public function say(){
   11         return "my name is {$this->name}";
   12     }
   13 }
   14 
   15 $obj = new Person(‘yach‘);
   16 echo $obj->say();

    

2. __destruct  析构方法

   1 public function __destruct(){
   2     echo "<p>{$this->name}被清理</p>";
   3 }
   4 
   5 # 后进先出 (弹夹原理)

    

3. __toString  对象说明

   class Usb
   {
       public function load(){
           echo "<p>load</p>";
       }
   
       public function __toString(){
           return ‘This is a obj‘;
       }
   }
   
   $obj = new Usb();
   echo $obj;

    

4. __call  访问对象不存在的方法时调用

    1 class Usb
    2 {
    3     public function load(){
    4         echo "<p>load</p>";
    5     }
    6 
    7     public function __call($i,$j){
    8         return "<p>您访问的方法<b>{$i}</b>不存在</p>";
    9     }
   10 }
   11 
   12 $obj = new Usb();
   13 echo $obj->start();

    

5. __get  提示无权限获取的方法

    1 class Usb
    2 {
    3     private function load(){
    4         echo "<p>load</p>";
    5     }
    6 
    7     public function __get($i){
    8         return "<p>您无权访问{$i}方法</p>";
    9     }
   10 }
   11 
   12 $obj = new Usb();
   13 echo $obj->load;

    

6. __set  提示无权限设置的方法

    1 class Usb
    2 {
    3     private $name = ‘yu‘;
    4 
    5     public function __set($i,$j){
    6         echo "<p>您无权设置{$i}为{$j}</p>";
    7     }
    8 }
    9 
   10 $obj = new Usb();
   11 $obj->name = ‘yach‘;

    

7. __isset  检测私有属性值是否被设定

    1 class Usb
    2 {
    3     private $name = ‘yu‘;
    4 
    5     public function __isset($i){
    6         return "<p>未设定{$i}属性</p>";
    7     }
    8 }
    9 
   10 $obj = new Usb();
   11 $b = isset($obj->name);
   12 echo $b;

    

8. __unset  无权删除提示

    1 class Usb
    2 {
    3     private $name = ‘yu‘;
    4 
    5     public function __unset($i){
    6         echo "<p>您无权删除{$i}属性</p>";
    7     }
    8 }
    9 
   10 $obj = new Usb();
   11 unset($obj->name);