Examples of using PHP Magic methods _php Tutorial

Examples of using the PHP magic method

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

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

When accessing a non-existent object property:

index.php

The code is as follows:

　　

Define (' BASEDIR ', __dir__); Defining a root directory constant

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

Spl_autoload_register (' \\common\\loader::autoload ');

$obj = new \common\object ();

When accessing a non-existent object property in PHP

Echo $obj->title;

Throws an error: notice:undefined property:common\object:: $title in D:\practise\php\design\psr0\index.php on line 9

After you add the __set and __get methods in common/object.php

object.php

The code is as follows:

　　

namespace Common;

Class object{

function __set ($key, $value) {

}

function __get ($key) {

}

}

Execute index.php again, 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 a root directory constant

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

Spl_autoload_register (' \\common\\loader::autoload ');

$obj = new \common\object ();

$obj->title = ' Hello ';

Echo $obj->title;

Execute index.php, page output:

The code is as follows:

String ' Common\object::__set ' (length=20)

String ' Common\object::__get ' (length=20)

Hello

②__call/__callstatic: A call to control the PHP object method (__callstatic is used to control the static method of the Class)

When executing a non-existent PHP method

index.php:

The code is as follows:

　　

Define (' BASEDIR ', __dir__); Defining a root directory constant

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

Spl_autoload_register (' \\common\\loader::autoload ');

$obj = new \common\object ();

When executing a non-existent PHP method

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

Execution index.php will report a fatal error: Fatal error:call to undefined method common\object::test () in D:\practise\php\design\psr0\ index.php on line 9

If you define a __call method in Common/object, the callback is automatically 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 function\n"; Returns a string as the return value

}

}

index.php

The code is as follows:

　　

Define (' BASEDIR ', __dir__); Defining a root directory constant

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

Spl_autoload_register (' \\common\\loader::autoload ');

$obj = new \common\object ();

When executing a non-existent PHP method

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 a static method that does not exist is called

common/object.php

The code is as follows:

　　

namespace Common;

Class object{

static function __callstatic ($name, $arguments) {

Var_dump ($name, $arguments);

Return "Magic function\n"; 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 a root directory constant

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

Spl_autoload_register (' \\common\\loader::autoload ');

Executes a static method that does not exist

echo common\object::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 a root directory constant

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

Spl_autoload_register (' \\common\\loader::autoload ');

$obj = new \common\object ();

Echo $obj;

This will cause an error: Catchable fatal error:object of class Common\object could not being converted to string in D:\PRACTISE\PHP\DESIGN\PSR 0\index.php on line 8

Adding __tostring methods in 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, this magic method is recalled

index.php

The code is as follows:

　　

Define (' BASEDIR ', __dir__); Defining a root directory constant

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

Spl_autoload_register (' \\common\\loader::autoload ');

$obj = new \common\object ();

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

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