PHP面向对象程序设计类的定义与用法简单示例

<?phpclass Person {  private $name;  private $sex;  private $age;  function __construct($name = "", $sex = "男", $age = 22) {    $this->name = $name;    $this->sex = $sex;    $this->age = $age;  }  // 直接为私有属性赋值时自动调用，可以屏蔽一些非法赋值  // 之前有版本可以设置方法为private function __set()  // The magic method __set() must have public visibility  // 因为5.35对魔术方法限制的严格了  public function __set($propertyName, $propertyValue) {    if ($propertyName == "sex") {      if (! ($propertyValue == "男" || $propertyValue == "女")) {        return;      }      if ($propertyValue > 150 || $propertyValue < 0) {        return;      }    }    // 根据传入的成员属性名,赋上相应的值    $this->$propertyName = $propertyValue;  }  // 用来获取私有属性  public function __get($propertyName) {    if (isset ( $this->$propertyName )) {      return ($this->$propertyName);    } else {      return (NULL);    }  }  public function __isset($propertyName) {    if ($propertyName == "name") {      return false; // 返回假，不允许在对象外部测定这个属性    }    return isset ( $this->$propertyName );  }  public function __unset($propertyName) {    if($propertyName=="name") {      return; //不允许删除name属性    }    unset($this->$propertyName);  }  function say() {    echo $this->name . "在说话<br/>";  }  function run() {    echo "在走路·<br/>";  }  function __destruct() {    echo "goodbye" . $this->name . "<br/>";  }}$person1 = new Person ();$person2 = new Person ( "2" );$person3 = new Person ( "3" );// 自动调用了__set()$person1->name = "张三";echo $person1->name;echo "<br/>";echo $person1->say ();// 自动调用了__get()echo $person1->age;echo "<br/>";var_dump ( isset ( $person1->name ) );echo "<br/>";unset($person1->name);echo "unset------------>".$person1->name;//name 没有被unset()echo "<br/>";$person2 = null;?>

张三张三在说话22bool(false)unset------------>张三goodbye2goodbye3goodbye张三