Examples of using PHP magic methods

This article mainly introduces the use of PHP magic methods, this article explains the __get, __set, __call, __callstatic, __tostring, __invoke, such as the use of magic methods, the need for friends can refer to the

①__get/__set: Takes over the properties of an object

When you access an object property that does not exist:

index.php

The code is as follows:

　　

Define (' BASEDIR ', __dir__); Defining Root Constants

Include BASEDIR. ' /common/loader.php ';

Spl_autoload_register (' commonloader::autoload ');

$obj = new Commonobject ();

When you access a nonexistent object property in PHP

Echo $obj->title;

Throws an error: notice:undefined property:commonobject:: $title in d:practisephpdesignpsr0index.php on line 9

When the __set and __get methods are added to the common/object.php

object.php

The code is as follows:

　　

namespace Common;

Class object{

function __set ($key, $value) {

}

function __get ($key) {

}

}

Again executes index.php, no more error.

Modify common/object.php again

The code is as follows:

　　

namespace Common;

Class object{

Protected $array = Array ();

function __set ($key, $value) {

Var_dump (__method__);

$this->array[$key] = $value;

}

function __get ($key) {

Var_dump (__method__);

return $this->array[$key];

}

}

index.php

The code is as follows:

　　

Define (' BASEDIR ', __dir__); Defining Root Constants

Include BASEDIR. ' /common/loader.php ';

Spl_autoload_register (' commonloader::autoload ');

$obj = new Commonobject ();

$obj->title = ' Hello ';

Echo $obj->title;

Execute index.php, page output:

The code is as follows:

String ' Commonobject::__set ' (length=20)

String ' Commonobject::__get ' (length=20)

Hello

②__call/__callstatic: Controls the invocation of the PHP object method (__callstatic to control the static method of the Class)

When you execute a PHP method that does not exist

index.php:

The code is as follows:

　　

Define (' BASEDIR ', __dir__); Defining Root Constants

Include BASEDIR. ' /common/loader.php ';

Spl_autoload_register (' commonloader::autoload ');

$obj = new Commonobject ();

When you execute a PHP method that does not exist

$obj->test (' Hello ', 123);

Execution index.php will report a fatal error: Fatal error:call to undefined method commonobject::test () into d:practisephpdesignpsr0index.php on Li NE 9

If a __call method is defined in Common/object, it is automatically recalled when the method does not exist:

The code is as follows:

　　

namespace Common;

Class object{

function __call ($func, $param) {//$func method name $param parameter

Var_dump ($func, $param);

Return "Magic Functionn"; Returns a string as the return value

}

}

index.php

The code is as follows:

　　

Define (' BASEDIR ', __dir__); Defining Root Constants

Include BASEDIR. ' /common/loader.php ';

Spl_autoload_register (' commonloader::autoload ');

$obj = new Commonobject ();

When you execute a PHP method that does not exist

echo $obj->test (' Hello ', 123);

Page output:

The code is as follows:

String ' Test ' (length=4)

Array

0 => string ' Hello ' (length=5)

1 => int 123

Magic function

When you call a static method that does not exist

common/object.php

The code is as follows:

　　

namespace Common;

Class object{

static function __callstatic ($name, $arguments) {

Var_dump ($name, $arguments);

Return "Magic Functionn"; Returns a string as the return value

}

}

Note: The __callstatic method is also declared as a static method

index.php

The code is as follows:

　　

Define (' BASEDIR ', __dir__); Defining Root Constants

Include BASEDIR. ' /common/loader.php ';

Spl_autoload_register (' commonloader::autoload ');

Executes a static method that does not exist

echo commonobject::test ("Hello", 1234);

Execute index.php, page output:

The code is as follows:

String ' Test ' (length=4)

Array

0 => string ' Hello ' (length=5)

1 => int 1234

Magic function

③__tostring: Converts a PHP object into a string

index.php

The code is as follows:

　　

Define (' BASEDIR ', __dir__); Defining Root Constants

Include BASEDIR. ' /common/loader.php ';

Spl_autoload_register (' commonloader::autoload ');

$obj = new Commonobject ();

Echo $obj;

Error: Catchable fatal error:object of class Commonobject could not is converted to string in D:practisephpdesignpsr0inde X.php on line 8

Add __tostring method to object.php

The code is as follows:

　　

namespace Common;

Class object{

function __tostring () {

return __class__;

}

}

④__invoke: When a PHP object is executed as a function, the Magic method is recalled

index.php

The code is as follows:

　　

Define (' BASEDIR ', __dir__); Defining Root Constants

Include BASEDIR. ' /common/loader.php ';

Spl_autoload_register (' commonloader::autoload ');

$obj = new Commonobject ();

echo $obj ("test");

object.php

The code is as follows:

　　

namespace Common;

Class object{

function __invoke ($param) {

Var_dump ($param);

Return ' Invoke ';

}

}

Page output:

The code is as follows:

String ' Test ' (length=4)

Invoke