php类相关知识---__unset和__isset

__unset 删除非公有属性，在外部调用unset时发生，  __isset用来检测对象属性是否设置值

<?php
class coach
{
    protected $chairfit = "徐晓冬";
    protected $lover = "丁大锅";
    public function __construct()
    {
        echo "欢迎来到~必图拳馆训练~";
    }
    public function __get($chairfit)
    {
        return $this->$chairfit;
    }
    public function __set($name,$value)
    {
        $this->$name=$value;
    }
}
class cj extends coach
{
   public $expertin = ['散打','泰拳','巴西柔术'];
}
$cj = new cj();
var_dump($cj);
$cj->lover='陈培昌';
var_dump(isset($cj->lover)) ;
?>

以为这样就能检测非公有属性是否设置？deeply sorry about that！

输出结果：

欢迎来到~必图拳馆训练~
bool(false)

正确姿势

<?php
class coach
{
    protected $chairfit = "徐晓冬";
    protected $lover = "丁大锅";
    public function __construct()
    {
        echo "欢迎来到~必图拳馆训练~"."\n";
    }
    public function __get($chairfit)
    {
        return $this->$chairfit;
    }
    public function __set($name,$value)
    {
        $this->$name=$value;
    }
　　 #加上这段
    public function __isset($name)
    {
        return isset($name);
    }
}
class cj extends coach
{
   public $expertin = ['散打','泰拳','巴西柔术'];
}
$cj = new cj();
//var_dump($cj);
$cj->lover='陈培昌';
var_dump(isset($cj->lover)) ;
?>

输出结果：

欢迎来到~必图拳馆训练~
bool(true)

<?php
class coach
{
    protected $chairfit = "徐晓冬";
    private $lover;
    public function __construct()
    {
        echo "欢迎来到~必图拳馆训练~"."\n";
    }
    public function __get($chairfit)
    {
        return $this->$chairfit;
    }
    public function __set($name,$value)
    {
        $this->$name=$value;
    }
    public function __isset($name)
    {
        return isset($name);
    }
    public function __unset($name)
    {
        unset($this->$name);
    }
}
class cj extends coach
{
   public $expertin = ['散打','泰拳','巴西柔术'];
}
$cj = new coach();
//var_dump($cj);
$cj->lover='陈培昌';
var_dump($cj);
unset($cj->lover);
var_dump($cj);

?>

unset cj对象的lover属性之前，打印对象结果为：

object(coach)#1 (2) {
["chairfit":protected]=>
string(9) "徐晓冬"
["lover":"coach":private]=>
string(9) "陈培昌"
}

删除之后打印对象结果

object(coach)#1 (1) {
["chairfit":protected]=>
string(9) "徐晓冬"
}