The Magic method in object-oriented oop in PHP

One, what is the Magic method:

PHP provides us with a series of functions that begin with __, which do not need to be called manually, and are called automatically at the right time, such functions as magic functions.
For example:

1	function__construct(){} 在new一个新对象时自动调用此函数

In PHP, there are magic methods and their effects:
1.__construct (): constructor, automatically called when new object

eg

Class person{public        $name;        public $age;                function __construct ($name, $age) {            $this->name= $name;            $this->age= $age;        }}

The __construct () function is automatically called when the new Person object is newly, assigning the passed arguments to $name, $age.

2.__destruct (): destructor, called automatically before an object is destroyed

Class person{public        $name;        public $age;               function __destruct () {        echo "This object has been destroyed";    }}

As mentioned above, this magic method is executed when the object is destroyed

3.__get (): automatically called when accessing private properties in a class, passing read property names, returning $this-> property names

Class person{        private $name;        public $age;                function __get ($name) {          return $this, $name;        }}

As in the code, the $name is set as a private property and cannot be read directly by $this->name;, so the __get () Magic method needs to be set to read.

4.__set (): Automatically called when assigning a value to a private property of a class, passing property names to be set, property values

Class person{        private $name;        public $age;                function __set ($key, $value) {            $this, $key = $value;        }}

With the __get () method, the private property cannot be set directly by $this->name= "AAA", the __set () method needs to be set, and the parameters passed in are the property name and the attribute value, respectively.

5.__isset (): Called when detecting private properties of an object using Isset, passing the detected property name, returning Isset ($this property name)

Class person{        private $name;        public $age;                function __isset ($name) {        return isset ($this, $name);}    }

Called when using Isset to detect the private properties of an object, as in the other.

6.__unset (): Called when the object private property is deleted using the unset () function, passing the deleted property name, executing the unset ($this-property name) in the method

Class person{        private $name;        public $age;                function __unset ($name) {
Unset ($this, $name);
}}

Ditto, called when a private property is removed with the unset () function.

7.__tostring (): Called When using echo to print an object, returns the content to be displayed when the object is printed, and returns a string

Class person{public        $name;        public $age;               function __tostring () {            $str = <<<str            The content you want to print is:<br>            \ $name =>{$this->name};< Br>            \ $age =>{$this->age};<br>str;            return $str;        }}

Called when you print an object with Echo, and returns what you want to display when you print the object.

8.__call (): called automatically when calling a method that is not defined or exposed in a class, passing the called function name and argument list

Class person{public        $name;        public $age;               function __call ($funcName, $funcParams) {            echo) {$funcName}, parameter list "you have called";            Print_r ($funcParams);            echo "does not exist/is not public";        }}
$zhangsan =new person ();
$zhangsan->say (a);

As shown in the code, the call does not exist for say (.

You call the function of the method, the parameter list array ([0] = 123) does not exist

9.__clone (): When cloning an object using the Clone keyword, it is called automatically to initialize the value of the newly cloned object

Class person{public        $name;        public $age;               function __clone () {        $this->name= "Lisi";        }}    $zhangsan =new person ("Zhangsan"), $lisi =clone $zhangsan, Echo $lisi->name;

The printed result is "Lisi", not "Zhangsan".

10.__sleep (): Automatically called when the object is serialized, returns an array where the values in the array are the properties that can be serialized

Class person{public        $name;        public $age;              function __sleep () {        return Array ("name", "Age");}    }

As in the above code, only "name" is used when serializing an object with serialize (), and the "age" property is serialized.

11.__wakeup (): Automatic invocation of object deserialization, initialization assignment for deserialization of newly generated objects

Class person{public        $name;        public $age;              function __wakeup () {        $this, name = "Lisi";    }}

Serializes the object and then deserializes it, assigning an initial value of "Lisi" to the object's Name property.

12.__autolode (): You need to declare a function outside the class, automatically call when an undeclared class is instantiated, pass the instantiated class name, and automatically load the corresponding class file using the class name.

function __autoload ($className) {    include "class/". Strtolower ($className). ". Class.php ";}    $zhangsan =new person (); $zhangsan->say ();

As the above code, the person class does not exist when calling the __autolode () method, loading a class written outside the file, "class/". Strtolower ($className). Class.php "; Is the relative path to the class file, $className is

The class name of the class that is not in this file, so the naming method must be a lowercase class name when creating an external class file. class.php. The __autolode () method is also the only one by one magic methods that are not written in the class.

The above is the Magic method in PHP, reasonable use of these methods can easily achieve the various operations of the object.

The Magic method in object-oriented oop in PHP