PHP编程：PHP之十六个魔术方法详细介绍

PHP学习
function __constrct([参数列表]){
  方法体 //通常用来对成员属性进行初始化赋值
}

PHP学习
<?php
  class Person
  {                                   
      public $name;    
      public $age;    
      public $sex;    
                                 
    /**
     * 显示声明一个构造方法且带参数
     */                                            
    public function __construct($name="", $sex="男", $age=22)
    {   
      $this->name = $name;
      $this->sex = $sex;
      $this->age = $age;
    }
    
    /**
     * say 方法
     */
    public function say()
    { 
      echo "我叫：" . $this->name . ",性别：" . $this->sex . ",年龄：" . $this->age;
    }  
                                              
  }

PHP学习
$Person1 = new Person();
echo $Person1->say(); //输出:我叫：,性别：男,年龄：27

PHP学习
$Person2 = new Person("小明");
echo $Person2->say(); //输出：我叫：张三,性别：男,年龄：27

PHP学习
$Person3 = new Person("李四","男",25);
echo $Person3->say(); //输出：我叫：李四,性别：男,年龄：25

PHP学习
function __destruct()
{
 //方法体
}

PHP学习
<?php
class Person{   
                            
  public $name;     
  public $age;     
  public $sex;     
                                  
  public function __construct($name="", $sex="男", $age=22)
  {  
    $this->name = $name;
    $this->sex = $sex;
    $this->age = $age;
  }
  
  /**
   * say 说话方法
   */
  public function say()
  { 
    echo "我叫：".$this->name.",性别：".$this->sex.",年龄：".$this->age;
  }  
  
  /**
   * 声明一个析构方法
   */
  public function __destruct()
  {
      echo "我觉得我还可以再抢救一下,我的名字叫".$this->name;
  }
}
$Person = new Person("小明");
unset($Person); //销毁上面创建的对象$Person

PHP学习
function __call(string $function_name, array $arguments)
{
  // 方法体
}

PHP学习
<?php
class Person
{               
  function say()
  { 
               
      echo "Hello, world!<br>"; 
  }   
    
  /**
   * 声明此方法用来处理调用对象中不存在的方法
   */
  function __call($funName, $arguments)
  { 
     echo "你所调用的函数：" . $funName . "(参数：" ; // 输出调用不存在的方法名
     print_r($arguments); // 输出调用不存在的方法时的参数列表
     echo ")不存在!<br>\n"; // 结束换行           
  }                     
}
$Person = new Person();      
$Person->run("teacher"); // 调用对象中不存在的方法,则自动调用了对象中的__call()方法
$Person->eat("小明", "苹果");       
$Person->say();  

PHP学习
<?php
class Person
{
  function say()
  {
    echo "Hello, world!<br>";
  }
  /**
   * 声明此方法用来处理调用对象中不存在的方法
   */
  public static function __callStatic($funName, $arguments)
  {
    echo "你所调用的静态方法：" . $funName . "(参数：" ; // 输出调用不存在的方法名
    print_r($arguments); // 输出调用不存在的方法时的参数列表
    echo ")不存在!<br>\n"; // 结束换行
  }
}
$Person = new Person();
$Person::run("teacher"); // 调用对象中不存在的方法,则自动调用了对象中的__call()方法
$Person::eat("小明", "苹果");
$Person->say();

PHP学习
<?php
class Person
{
  private $name;
  private $age;
  function __construct($name="", $age=1)
  {
    $this->name = $name;
    $this->age = $age;
  }
  /**
   * 在类中添加__get()方法,在直接获取属性值时自动调用一次,以属性名作为参数传入并处理
   * @param $propertyName
   *
   * @return int
   */
  public function __get($propertyName)
  {  
    if ($propertyName == "age") {
      if ($this->age > 30) {
        return $this->age - 10;
      } else {
        return $this->$propertyName;
      }
    } else {
      return $this->$propertyName;
    }
  }
}
$Person = new Person("小明", 60);  // 通过Person类实例化的对象,并通过构造方法为属性赋初值
echo "姓名：" . $Person->name . "<br>";  // 直接访问私有属性name,自动调用了__get()方法可以间接获取
echo "年龄：" . $Person->age . "<br>";  // 自动调用了__get()方法,根据对象本身的情况会返回不同的值

PHP学习
<?php
class Person
{
  private $name;
  private $age;
  public function __construct($name="", $age=25)
  {
    $this->name = $name;
    $this->age = $age;
  }
  /**
   * 声明魔术方法需要两个参数,真接为私有属性赋值时自动调用,并可以屏蔽一些非法赋值
   * @param $property
   * @param $value
   */
  public function __set($property, $value) {
    if ($property=="age")
    {
      if ($value > 150 || $value < 0) {
        return;
      }
    }
    $this->$property = $value;
  }
  /**
   * 在类中声明说话的方法,将所有的私有属性说出
   */
  public function say(){
    echo "我叫".$this->name.",今年".$this->age."岁了";
  }
}
$Person=new Person("小明", 25); //注意,初始值将被下面所改变
//自动调用了__set()函数,将属性名name传给第一个参数,将属性值”李四”传给第二个参数
$Person->name = "小红";   //赋值成功.如果没有__set(),则出错.
//自动调用了__set()函数,将属性名age传给第一个参数,将属性值26传给第二个参数
$Person->age = 16; //赋值成功
$Person->age = 160; //160是一个非法值,赋值失效
$Person->say(); //输出：我叫小红,今年16岁了

PHP学习
<?php
class Person
{
  public $sex;
  private $name;
  private $age;
  public function __construct($name="", $age=25, $sex='男')
  {
    $this->name = $name;
    $this->age = $age;
    $this->sex = $sex;
  }
  /**
   * @param $content
   *
   * @return bool
   */
  public function __isset($content) {
    echo "当在类外部使用isset()函数测定私有成员{$content}时,自动调用<br>";
    echo isset($this->$content);
  }
}
$person = new Person("小明", 25); // 初始赋值
echo isset($person->sex),"<br>";
echo isset($person->name),"<br>";
echo isset($person->age),"<br>";

PHP学习
<?php
class Person
{
  public $sex;
  private $name;
  private $age;
  public function __construct($name="", $age=25, $sex='男')
  {
    $this->name = $name;
    $this->age = $age;
    $this->sex = $sex;
  }
  /**
   * @param $content
   *
   * @return bool
   */
  public function __unset($content) {
    echo "当在类外部使用unset()函数来删除私有成员时自动调用的<br>";
    echo isset($this->$content);
  }
}
$person = new Person("小明", 25); // 初始赋值
unset($person->sex);
unset($person->name);
unset($person->age);

PHP学习
<?php
class Person
{
  public $sex;
  public $name;
  public $age;
  public function __construct($name="", $age=25, $sex='男')
  {
    $this->name = $name;
    $this->age = $age;
    $this->sex = $sex;
  }
  /**
   * @return array
   */
  public function __sleep() {
    echo "当在类外部使用serialize()时会调用这里的__sleep()方法<br>";
    $this->name = base64_encode($this->name);
    return array('name', 'age'); // 这里必须返回一个数值,里边的元素表示返回的属性名称
  }
}
$person = new Person('小明'); // 初始赋值
echo serialize($person);
echo '<br/>';

PHP学习
<?php
class Person
{
  public $sex;
  public $name;
  public $age;
  public function __construct($name="", $age=25, $sex='男')
  {
    $this->name = $name;
    $this->age = $age;
    $this->sex = $sex;
  }
  /**
   * @return array
   */
  public function __sleep() {
    echo "当在类外部使用serialize()时会调用这里的__sleep()方法<br>";
    $this->name = base64_encode($this->name);
    return array('name', 'age'); // 这里必须返回一个数值,里边的元素表示返回的属性名称
  }
  /**
   * __wakeup
   */
  public function __wakeup() {
    echo "当在类外部使用unserialize()时会调用这里的__wakeup()方法<br>";
    $this->name = 2;
    $this->sex = '男';
    // 这里不需要返回数组
  }
}
$person = new Person('小明'); // 初始赋值
var_dump(serialize($person));
var_dump(unserialize(serialize($person)));

PHP学习
<?php
class Person
{
  public $sex;
  public $name;
  public $age;
  public function __construct($name="", $age=25, $sex='男')
  {
    $this->name = $name;
    $this->age = $age;
    $this->sex = $sex;
  }
  public function __toString()
  {
    return 'go go go';
  }
}
$person = new Person('小明'); // 初始赋值
echo $person;

PHP学习
<?php
class Person
{
  public $sex;
  public $name;
  public $age;
  public function __construct($name="", $age=25, $sex='男')
  {
    $this->name = $name;
    $this->age = $age;
    $this->sex = $sex;
  }
  
}
$person = new Person('小明'); // 初始赋值
echo $person;

PHP学习
<?php
class Person
{
  public $sex;
  public $name;
  public $age;
  public function __construct($name="", $age=25, $sex='男')
  {
    $this->name = $name;
    $this->age = $age;
    $this->sex = $sex;
  }
  public function __invoke() {
    echo '这可是一个对象哦';
  }
}
$person = new Person('小明'); // 初始赋值
$person();

PHP学习
<?php
class Person
{
  public $sex;
  public $name;
  public $age;
  public function __construct($name="", $age=25, $sex='男')
  {
    $this->name = $name;
    $this->age = $age;
    $this->sex = $sex;
  }
}
$person = new Person('小明'); // 初始赋值
var_export($person);

PHP学习
<?php
class Person
{
  public $sex;
  public $name;
  public $age;
  public function __construct($name="", $age=25, $sex='男')
  {
    $this->name = $name;
    $this->age = $age;
    $this->sex = $sex;
  }
  public static function __set_state($an_array)
  {
    $a = new Person();
    $a->name = $an_array['name'];
    return $a;
  }
}
$person = new Person('小明'); // 初始赋值
$person->name = '小红';
var_export($person);

PHP学习
<?php
class Person
{
  public $sex;
  public $name;
  public $age;
  public function __construct($name="", $age=25, $sex='男')
  {
    $this->name = $name;
    $this->age = $age;
    $this->sex = $sex;
  }
  public function __clone()
  {
    echo __METHOD__."你正在克隆对象<br>";
  }
}
$person = new Person('小明'); // 初始赋值
$person2 = clone $person;
var_dump('persion1:');
var_dump($person);
echo '<br>';
var_dump('persion2:');
var_dump($person2);

PHP学习
/** 
 * 文件non_autoload.php 
 */ 
  
require_once('project/class/A.php'); 
require_once('project/class/B.php'); 
require_once('project/class/C.php'); 
  
if (条件A) { 
  $a = new A(); 
  $b = new B(); 
  $c = new C(); 
  // … 业务逻辑 
} else if (条件B) { 
  $a = newA(); 
  $b = new B(); 
  // … 业务逻辑 
}

PHP学习
/** 
 * 文件autoload_demo.php 
 */ 
function __autoload($className) { 
  $filePath = “project/class/{$className}.php”; 
  if (is_readable($filePath)) { 
    require($filePath); 
  } 
} 
  
if (条件A) { 
  $a = new A(); 
  $b = new B(); 
  $c = new C(); 
  // … 业务逻辑 
} else if (条件B) { 
  $a = newA(); 
  $b = new B(); 
  // … 业务逻辑 
}

PHP学习
<?php
class C {
  private $prop;
  public function __construct($val) {
    $this->prop = $val;
  }
  /**
   * @return array
   */
  public function __debugInfo() {
    return [
      'propSquared' => $this->prop ** 2,
    ];
  }
}
var_dump(new C(42));