我不是PHP开发人员,所以我想知道在PHP中使用显式getter/setter的优点和缺点是什么,在纯OOP风格中,带有私有字段(我喜欢的方式):

class MyClass {
    private $firstField;
    private $secondField;

    public function getFirstField() {
        return $this->firstField;
    }
    public function setFirstField($x) {
        $this->firstField = $x;
    }
    public function getSecondField() {
        return $this->secondField;
    }
    public function setSecondField($x) {
        $this->secondField = $x;
    }
}

或者只是公共字段:

class MyClass {
    public $firstField;
    public $secondField;
}

当前回答

如果你喜欢使用__call函数,你可以使用这个方法。它适用于

GET => $this->属性() SET => $this->属性($value) getProperty() => $this-> SET => $this->setProperty($value)

kalsdas

public function __call($name, $arguments) {

    //Getting and setting with $this->property($optional);

    if (property_exists(get_class($this), $name)) {


        //Always set the value if a parameter is passed
        if (count($arguments) == 1) {
            /* set */
            $this->$name = $arguments[0];
        } else if (count($arguments) > 1) {
            throw new \Exception("Setter for $name only accepts one parameter.");
        }

        //Always return the value (Even on the set)
        return $this->$name;
    }

    //If it doesn't chech if its a normal old type setter ot getter
    //Getting and setting with $this->getProperty($optional);
    //Getting and setting with $this->setProperty($optional);
    $prefix = substr($name, 0, 3);
    $property = strtolower($name[3]) . substr($name, 4);
    switch ($prefix) {
        case 'get':
            return $this->$property;
            break;
        case 'set':
            //Always set the value if a parameter is passed
            if (count($arguments) != 1) {
                throw new \Exception("Setter for $name requires exactly one parameter.");
            }
            $this->$property = $arguments[0];
            //Always return the value (Even on the set)
            return $this->$name;
        default:
            throw new \Exception("Property $name doesn't exist.");
            break;
    }
}

其他回答

在阅读了其他建议后,我倾向于这样说:

作为GENERIC规则,你不会总是为所有属性定义setter,特别是“内部”属性(信号量、内部标志……)。只读属性显然没有setter,所以有些属性只有getter;这就是__get()缩小代码的地方:

define a __get() (magical global getters) for all those properties which are alike, group them in arrays so: they'll share common characteristics: monetary values will/may come up properly formatted, dates in an specific layout (ISO, US, Intl.), etc. the code itself can verify that only existing & allowed properties are being read using this magical method. whenever you need to create a new similar property, just declare it and add its name to the proper array and it's done. That's way FASTER than defining a new getter, perhaps with some lines of code REPEATED again and again all over the class code.

是的!我们也可以写一个私有方法来做到这一点,但话又说回来,我们将声明许多方法(++内存),最终调用另一个总是相同的方法。为什么不写一个单一的方法来管理它们呢?(是的!双关语!)):

Magic setter也可以只响应特定的属性,因此可以单独在一个方法中筛选所有日期类型属性的无效值。如果日期类型属性列在数组中,则可以轻松定义它们的setter。当然,这只是一个例子。有太多的情况。

About readability... Well... That's another debate: I don't like to be bound to the uses of an IDE (in fact, I don't use them, they tend to tell me (and force me) how to write... and I have my likes about coding "beauty"). I tend to be consistent about naming, so using ctags and a couple of other aids is sufficient to me... Anyway: once all this magic setters and getters are done, I write the other setters that are too specific or "special" to be generalized in a __set() method. And that covers all I need about getting and setting properties. Of course: there's not always a common ground, or there are such a few properties that is not worth the trouble of coding a magical method, and then there's still the old good traditional setter/getter pair.

编程语言就是人类的人工语言。因此,它们都有自己的语调或重音、语法和风格,所以我不会假装用与Java或c#相同的“重音”来编写Ruby或Python代码,也不会编写类似Perl或SQL的JavaScript或PHP……用他们该用的方式去使用他们。

为什么使用getter和setter ?

可伸缩性:重构getter比在项目代码中搜索所有的var赋值更容易。 调试:可以在setter和getter中设置断点。 更简洁:神奇的函数不是很好的解决方案,你的IDE不会建议代码。最好使用模板来快速编写getter。

这篇文章不是专门关于__get和__set,而是关于__call,除了方法调用之外,它们是相同的思想。作为一种规则,我远离任何类型的允许重载的魔法方法,原因概述在评论和帖子中,然而,我最近遇到了一个第三方API,我使用了一个服务和一个子服务,例如:

http://3rdparty.api.com?service=APIService.doActionOne&apikey=12341234

这里重要的部分是,这个API除了子操作(在本例中为doActionOne)之外,其他内容都是相同的。这个想法是开发人员(我自己和其他使用这个类的人)可以通过名称调用子服务,而不是像这样:

$myClass->doAction(array('service'=>'doActionOne','args'=>$args));

我可以这样做:

 $myClass->doActionOne($args);

对于硬编码来说,这只是大量的重复(这个例子非常类似于代码):

public function doActionOne($array)
    {
        $this->args     =   $array;
        $name           =   __FUNCTION__;
        $this->response =   $this->executeCoreCall("APIService.{$name}");
    }

public function doActionTwo($array)
    {
        $this->args     =   $array;
        $name           =   __FUNCTION__;
        $this->response =   $this->executeCoreCall("APIService.{$name}");
    }

public function doActionThree($array)
    {
        $this->args     =   $array;
        $name           =   __FUNCTION__;
        $this->response =   $this->executeCoreCall("APIService.{$name}");
    }

protected function executeCoreCall($service)
    {
        $cURL = new \cURL();
        return $cURL->('http://3rdparty.api.com?service='.$service.'&apikey='.$this->api.'&'.http_build_query($this->args))
                    ->getResponse();
    }

但是使用神奇的__call()方法,我能够使用动态方法访问所有服务:

public function __call($name, $arguments)
    {
        $this->args     =   $arguments;
        $this->response =   $this->executeCoreCall("APIService.{$name}");   
        return $this;
    }

这种动态调用数据返回的好处是,如果供应商添加了另一个子服务,我不必向类中添加另一个方法或创建扩展类等。我不确定这是否对任何人都有用,但我想我会展示一个例子,其中__set, __get, __call等可能是一个考虑的选项,因为主要函数是数据的返回。


编辑:

巧合的是,我在帖子发布几天后看到了这篇文章,它准确地概述了我的场景。这不是我指的API,但方法的应用是相同的:

我是否正确使用api ?

class MyClass {
    private $firstField;
    private $secondField;
    private $thirdField;

    public function __get( $name ) {
        if( method_exists( $this , $method = ( 'get' . ucfirst( $name  ) ) ) )
            return $this->$method();
        else
            throw new Exception( 'Can\'t get property ' . $name );
    }

    public function __set( $name , $value ) {
        if( method_exists( $this , $method = ( 'set' . ucfirst( $name  ) ) ) )
            return $this->$method( $value );
        else
            throw new Exception( 'Can\'t set property ' . $name );
    }

    public function __isset( $name )
    {
        return method_exists( $this , 'get' . ucfirst( $name  ) ) 
            || method_exists( $this , 'set' . ucfirst( $name  ) );
    }

    public function getFirstField() {
        return $this->firstField;
    }

    protected function setFirstField($x) {
        $this->firstField = $x;
    }

    private function getSecondField() {
        return $this->secondField;
    }
}

$obj = new MyClass();

echo $obj->firstField; // works
$obj->firstField = 'value'; // works

echo $obj->getFirstField(); // works
$obj->setFirstField( 'value' ); // not works, method is protected

echo $obj->secondField; // works
echo $obj->getSecondField(); // not works, method is private

$obj->secondField = 'value'; // not works, setter not exists

echo $obj->thirdField; // not works, property not exists

isset( $obj->firstField ); // returns true
isset( $obj->secondField ); // returns true
isset( $obj->thirdField ); // returns false

准备好了!

一般来说,第一种方法总体上更受欢迎,因为具有编程知识的人可以轻松地转换到PHP,并以面向对象的方式完成工作。第一种方法更为普遍。我的建议是坚持使用在许多语言中都行之有效的方法。然后,当你使用另一种语言时,你将准备好完成一些事情(而不是花时间重新发明轮子)。