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。
<?php
class 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();
$p1->age = 25;
?>
执行结果
My name is Tom,and my age is 23,sex is Male Fatal error: Call to private method Person::Walk() from context ‘‘ in C:\phpStudy\WWW\php\lei\FengZhuang.php on line 25 Fatal error: Cannot access private property Person::$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
<?php
class 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
