设置私有成员
使用private关键字来设置私有成员，完成对成员的封装，封装后的成员在对象的外部不能被访问，如果访问会出现错误，在对象的内部能访问被封装的成员属性和方法。
<?phpclass Person{//封装属性private $name;private $age;private $sex;function __construct($name="Tom",$age=23,$sex="Male"){$this->name = $name;$this->age = $age;$this->sex = $sex;}function Say(){echo "My name is ".$this->name.",and my age is ".$this->age.",sex is ".$this->sex;}private function Walk(){echo $this->name." is Walk.";}}$p1 = new Person();$p1->Say();$p1->Walk();$p1->age = 25;?>执行结果
My name is Tom,and my age is 23,sex is MaleFatal error: Call to private method Person::Walk() from context ‘‘ in C:\phpStudy\WWW\php\lei\FengZhuang.php on line 25Fatal error: Cannot access private property Person::$age in C:\phpStudy\WWW\php\lei\FengZhuang.php on line 26
私有成员的访问
在对象外如果想获取私有属性的值，或者想给私有属性赋值，可以使用public关键字或者在对象内部声明一些操作私有属性的方法
类中的构造方法默认为公有方法，构造方法不要设置成私有的
<?phpclass Person{private $name;private $age;private $sex;function __construct($name="Tom",$age=23,$sex="Male"){$this->name = $name;$this->age = $age;$this->sex = $sex;}function Say(){echo "My name is ".$this->name.",and my age is ".$this->age.",sex is ".$this->sex;echo "<br>";}public function Walk(){echo $this->name." is Walk.";echo "<br>";}public function SetAge($age){if($age >100 || $age <0)return;else$this->age = $age;return $this->age;}}$p1 = new Person();$p1->Say();$p1->Walk();$p1->SetAge(53);?>运行结果
PHP类(三)-类的封装
原文地址：https://www.cnblogs.com/sch01ar/p/8146699.html