PHP-php：关于间接调用__set和__get

Question

<?php 
    class classname
    {
        public $attribute;
        function __get($name)
        {
            echo "This is get function<br />";
            return $this->$name;
        }
        function __set($name,$value)
        {
            echo "This is set function<br />";
            $this->$name=$value;
        }
    }

    $a=new classname();
        //测试1
    $a->attribute="demo";
    echo $a->attribute;

        //测试2
    //$a->__set("attribute","demo");
    //echo $a->__get("attribute")."<br />";
?> 

Answer 1

public $attribute;
改为:
private $attribute;