常见的几种魔术变量

class Tets{
    private $a = ‘‘;
    public function __set($var,$val){
        $this->$val = $val;
    }
    public function __get($var){
        return $this->$var;
    }
}

$test = new Test();
$test->a = ‘abc‘;     //如果没有设置__set会报错，因为外部不能调用private的变量
var_dump($this->a);

class Test{
    private $abc = ‘abc‘;

    public function __isset($var){
        return isset($this->$var)?true:false;
    }
}
$test= new Test();
var_dump(isset($test->abc));

class Test{
    private $abc = ‘abc‘;

    public function __unset($var){
        unset($this->$var);
    }
}
$test = new Test();
unset($test->abc);

class Test{
    public function __call($func,$arguments){
        echo($func."<br/>");
        print_r($arguments);
    }
}

$test = new Test();
$test->go(1,‘ok‘); //当实例化对象没有找到方法，就会自动调用__call();

class Test{
    public static function __callStatic($func,$arguments){
                echo($func."<br/>");
        print_r($arguments);
    }
}
Test::go(1,‘ok‘);  //没有找到类方法就自动调用__callStatic()

class Test{
    public function __invoke($arg){
        var_dump($arg);
    }
}

$test = new Test();
$test(‘go....‘);  //直接将实例化的对象当做函数来执行就用__invoke()

class Test{
    public function __toString(){
        return "hello;;;";
    }
}

$test = new Test();
echo $test;   //直接打印实例化对象，就可以使用__toString