《PHP與MySQL程式設計》第六章

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用_ _set()方法設定屬性

boolean __set([string property_name] , [mixed value_to_assign])

自己寫了個容易理解的

<?phpclass Employee{    var $name;    function __set($propName, $propValue)    {        echo ‘$name =‘ . $this->name . ‘<br/>‘;        echo ‘$propName = ‘ . $propName . ‘<br/>‘;        echo ‘$propValue = ‘ . $propValue . "<br/>";                $this->$propName = $propValue;    }        }$employee = new Employee();$employee->name = "Mario";$employee->title = "Exective chef";echo $employee->title;//輸出// $name =Mario// $propName = title// $propValue = Exective chef

 

__set()方法是預設的，我測試了一下，我不寫__set()方法，也可以實現

$employee->sex = ‘M‘;

echo $employee->sex;

__set()的方法可以限制一些屬性的設定，比如：

<?phpclass Employee{    var $name;    function __set($propName, $propValue)    {        if ($propName == ‘age‘) {            if ($propValue < 18 || $propValue > 60) {                $this->$propName = null;            } else {                $this->$propName = $propValue;            }        } else {            $this->$propName = $propValue;        }    }}$employee = new Employee();$employee->name = "Mario";$employee->age = "17";$employee->page = 1;echo ‘name = ‘ . $employee->name . ‘<br/>‘;echo ‘age = ‘ . $employee->age . ‘<br/>‘;echo ‘page = ‘ . $employee->page;//輸出 僱員的年齡小於18或大於60的時候age=null// name = Mario// age =// page = 1

 

 

 

用 _ _get()方法擷取屬性

boolean __get([string property_name])

 

測試

結論：

當屬性存在的時候，__set()和__get()是不僅過的。測試例子如下->

<?phpclass Employee{    public $name;    public $city;    protected $wage;        function __set($propName, $propValue)    {        echo "__set called!<br/>";$this->$propName = $propValue;    }        function __get($propName)    {        echo "__get called!<br/>";        $vars = array(            "name",            "city"        );                if (in_array($propName, $vars)) {            return $this->$porpName;        } else {            return "No such variable!";        }    }        }$employee = new Employee();$employee->name = "Mario";$employee->city = "shan";echo $employee->name . "<br/>";echo $employee->city . "<br/>";// 輸出// Mario// shan

 

在下面加入下的代碼->

$employee->age = 20;echo $employee->age . "<br/>";// 輸出// __set called!// 20echo $employee->sex . "<br/>";//輸出// __get called!// No such variable!

如果在$vars數組中加入sex的話，程式報錯！

 

看下來感覺沒什麼亮點，用不起來。

 

《PHP與MySQL程式設計》第六章