PHP Magic Method Use Example _php instance

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

When you access an object property that does not exist:

index.php

Copy Code code as follows:

<?php
Define (' BASEDIR ', __dir__); Defining Root Constants
Include BASEDIR. ' /common/loader.php ';
Spl_autoload_register (' \\common\\loader::autoload ');

$obj = new \common\object ();

When you access a nonexistent 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

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

object.php

Copy Code code as follows:

<?php
namespace Common;

Class object{
function __set ($key, $value) {
}

function __get ($key) {
}
}

Again executes index.php, no more error.

Modify common/object.php again

Copy Code code as follows:

<?php
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

Copy Code code as follows:

<?php
Define (' BASEDIR ', __dir__); Defining Root Constants
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:

Copy Code code as follows:

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

Copy Code code as follows:

<?php
Define (' BASEDIR ', __dir__); Defining Root Constants
Include BASEDIR. ' /common/loader.php ';
Spl_autoload_register (' \\common\\loader::autoload ');

$obj = new \common\object ();

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 common\object::test () in D:\practise\php\design\psr0\ index.php on line 9

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

Copy Code code as follows:

<?php
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

Copy Code code as follows:

<?php
Define (' BASEDIR ', __dir__); Defining Root Constants
Include BASEDIR. ' /common/loader.php ';
Spl_autoload_register (' \\common\\loader::autoload ');

$obj = new \common\object ();

When you execute a PHP method that does not exist
echo $obj->test (' Hello ', 123);

Page output:

Copy Code code 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

Copy Code code as follows:

<?php
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

Copy Code code as follows:

<?php
Define (' BASEDIR ', __dir__); Defining Root Constants
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:

Copy Code code 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

Copy Code code as follows:

<?php
Define (' BASEDIR ', __dir__); Defining Root Constants
Include BASEDIR. ' /common/loader.php ';
Spl_autoload_register (' \\common\\loader::autoload ');

$obj = new \common\object ();

Echo $obj;

Error: Catchable fatal error:object of class Common\object could not is converted to string in D:\PRACTISE\PHP\DESIGN\PSR 0\index.php on line 8

Add __tostring method to object.php

Copy Code code as follows:

<?php
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

Copy Code code as follows:

<?php
Define (' BASEDIR ', __dir__); Defining Root Constants
Include BASEDIR. ' /common/loader.php ';
Spl_autoload_register (' \\common\\loader::autoload ');

$obj = new \common\object ();

echo $obj ("test");

object.php

Copy Code code as follows:

<?php
namespace Common;

Class object{
function __invoke ($param) {
Var_dump ($param);
Return ' Invoke ';
}
}

Page output:

Copy Code code as follows:

String ' Test ' (length=4)
Invoke