php魔术方法__isset与__unset实例教程

<?php
/**
 * 针对类中的魔术方法 __isset() 和 __unset() 的例子
*/ www.jb200.com
class Example {
    public $public;
    protected $protected;
    private $private;
    
    public function __construct(){
        $this->public = 'pub';
        $this->protected = 'pro';
        $this->private = 'pri';
    }
    
    public function __isset($var){
        echo '这里通过__isset()方法查看属性名为 '.$var."n";
    }
    
    public function __unset($var){
        echo '这里通过__unset()方法要销毁属性名为 '.$var."n";
    }
}
 
$exa = new Example;
 
echo '<pre>';
var_dump(isset($exa->public));
echo "n";
var_dump(isset($exa->protected));
echo "n";
var_dump(isset($exa->private));
echo "n";
var_dump(isset($exa->noVar));
echo "n";
echo '<hr/>';
 
unset($exa->public);
var_dump($exa);
 
echo "n";
unset($exa->protected);
echo "n";
unset($exa->private);
echo "n";
unset($exa->noVar);
echo "n";