php 给对象私有及受保护的成员变量赋值的几种方法

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1.构造方法赋值

<?phpclass City{private $_cityName;private $_population;//function city($_cityName,$_population){}  php5.3.3起在有命名空间的类中，类同名方法不再视为构造方法而是常规方法，无命名空间类中不影响public function __construct($_cityName,$_population){$this->_cityName = $_cityName;$this->_population = $_population;}public function getCityName(){return $this->_cityName;}public function getPopulation(){return $this->_population;}}$nanjing = new City('南京',10000000);echo '城市：'.$nanjing->getCityName(),'<br/>';//城市：南京echo '人口：'.$nanjing->getPopulation(),'<br/>';//人口：10000000

2.魔术方式赋值和调用：__set()、__get()

<?phpclass City{private $_cityName;private $_population;//magic method: __set()  /**当给一个无访问权限或不存在的属性赋值时，__set()魔术方法会自动调用，并传入两个参数：属性和属性值$suzhou->_cityName='苏州' ---无权访问权限--> __set('_cityName','苏州');**/public function __set($property_name,$property_value){$this->$property_name = $property_value;}//magic method: __get()/**当我们调用一个权限上不允许访问的属性或者是不存在的属性时，__get()魔术方法会自动调用，并且自动传参，参数名是属性名$suzhou->_cityName ---无访问权限--> __get(_cityName);**/public function __get($property_name){if(isset($this->$property_name)){return $this->$property_name;}else{return null;}}}//设置__set()和__get()方法，可以在类外部像给public修饰的成员变量一样赋值和调用$suzhou = new City();$suzhou->_cityName = '苏州';  $suzhou->_population = 7000000;echo '城市：'.$suzhou->_cityName,'<br/>';//城市：苏州echo '人口：'.$suzhou->_population,'<br/>';//人口：7000000

3.调用类常规方法传参赋值

<?phpclass City{private $_cityName;private $_population;private $_factory;function setCityName($_cityName){$this->_cityName = $_cityName; }function setPopulation($_population){$this->_population = $_population;}function getCityName(){return $this->_cityName;}function getPopulation(){return $this->_population;}//function set($name,$value){$this->_factory[$name] = $value;//以数组的形式存储变量赋值}function get($name){return $this->_factory[$name];}}$shanghai = new City();//通过函数传参的形式给对象指定私有变量赋值，通过指定函数获取指定私有变量值$shanghai->setCityName('上海'); $shanghai->setPopulation(30000000);echo '城市：'.$shanghai->getCityName(),'<br/>';  //城市：上海echo '人口：'.$shanghai->getPopulation(),'<br/>';//人口：30000000$shanghai->set('totalArea','6340平方公里');$shanghai->set('areaCode','017');$shanghai->set('zipCode',200000);echo '面积：'.$shanghai->get('totalArea'),'<br/>';//面积：6340平方公里echo '区号：'.$shanghai->get('areaCode'),'<br/>';//区号：017echo '邮编：'.$shanghai->get('zipCode'),'<br/>';//邮编：200000

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