php教程

预定义类

本节列出标准的预定义类。各种扩展库定义了其它类，其说明在各自的参考文档中。

标准类

这些类由一些内建在 PHP 中的标准函数定义。

Directory
由dir()创建.
stdClass
Created by typecasting to object.
__PHP_Incomplete_Class
Possibly created by unserialize().

自 PHP 5 起预定义的类

这些额外的预定义类是 PHP 5.0.0 引进的。

exception
ErrorException
Available since PHP 5.1.0.
php_user_filter

Closure

PHP5.3.0中引入了一个预定义的final类Closure，它可以用于实现 匿名函数

关于更多信息，可以查看匿名函数.

Generator

The predefined final class Generator was introduced in PHP 5.5.0. It is used for representing generators.

For more information, see its class page.

从PHP 7开始预定义的类和接口

这些预定义的类和接口是在PHP 7.0.0 中开始引入的。

ArithmeticError
AssertionError
DivisionByZeroError
Error
Throwable
ParseError
TypeError

特殊的类

以下这些标识符由于它们有特殊的用处，因此不可作为类名

self
Current class.
static
Current class in runtime.
parent
Parent class.

User Contributed Notes

xzero at elite7hackers dot net 08-Sep-2017 08:37
There comes improved version of amazing snippet posted by (spark at limao dot com dot br)  which allows dynamic methods generations and works as versatile extension of StdClass:

This one is faster, optimised for closures, and will work only with closures. Compatible: >= PHP 5.6
<?php

class Dynamic extends \stdClass
{
    public function __call($key, $params)
    {
        if ( ! isset($this->{$key})) {
            throw new Exception("Call to undefined method " . __CLASS__ . "::" . $key . "()");
        }

        return $this->{$key}->__invoke(... $params);
    }
}

?>

Usage examples:

<?php
$dynamic                = new Dynamic();
$dynamic->anotherMethod = function () {
    echo "Hey there";
};
$dynamic->randomInt     = function ($min, $max) {
    return mt_rand($min, $max); // random_int($min, $max); // <-- PHP7+
};

var_dump(
    $dynamic->randomInt(1, 11),
    $dynamic->anotherMethod()
);
?>

This will accept arrays, strings and Closures but is a bit slower due to call_user_func_array
<?php

class Dynamic extends \stdClass
{
    public function __call($key, $params)
    {
        if ( ! isset($this->{$key})) {
            throw new Exception("Call to undefined method " . __CLASS__ . "::" . $key . "()");
        }

        return call_user_func_array($this->{$key}, $params);
    }
}

?>

Usage examples:
<?php
$dynamic                = new Dynamic();
$dynamic->myMethod      = "thatFunction";
$dynamic->hisMethod     = array($dynamic, "randomInt");
$dynamic->newMethod     = array(SomeClass, "staticMethod");
$dynamic->anotherMethod = function () {
    echo "Hey there";
};
$dynamic->randomInt     = function ($min, $max) {
    return mt_rand($min, $max); // random_int($min, $max); // <-- PHP7+
};

var_dump(
    $dynamic->randomInt(1, 11),
    $dynamic->anotherMethod(),
    $dynamic->hisMethod()
);

?>
xzero at elite7hackers dot net 08-Sep-2017 08:32
There comes improved version of amazing snippet posted by which allows dynamic methods generations and works as versatile extension of StdClass:

This one is faster, optimised for closures, and will work only with closures. Compatible: >= PHP 5.6
<?php

class Dynamic extends \stdClass
{
    public function __call($key, $params)
    {
        if ( ! isset($this->{$key})) {
            throw new Exception("Call to undefined method " . __CLASS__ . "::" . $key . "()");
        }

        return $this->{$key}->__invoke(... $params);
    }
}

?>

Usage examples:

<?php
$dynamic                = new Dynamic();
$dynamic->anotherMethod = function () {
    echo "Hey there";
};
$dynamic->randomInt     = function ($min, $max) {
    return mt_rand($min, $max); // random_int($min, $max); // <-- PHP7+
};

var_dump(
    $dynamic->randomInt(1, 11),
    $dynamic->anotherMethod()
);
?>

This will accept arrays, strings and Closures but is a bit slower due to call_user_func_array
<?php

class Dynamic extends \stdClass
{
    public function __call($key, $params)
    {
        if ( ! isset($this->{$key})) {
            throw new Exception("Call to undefined method " . __CLASS__ . "::" . $key . "()");
        }

        return call_user_func_array($this->{$key}, $params);
    }
}

?>

Usage examples:
<?php
$dynamic                = new Dynamic();
$dynamic->myMethod      = "thatFunction";
$dynamic->hisMethod     = array($dynamic, "randomInt");
$dynamic->newMethod     = array(SomeClass, "staticMethod");
$dynamic->anotherMethod = function () {
    echo "Hey there";
};
$dynamic->randomInt     = function ($min, $max) {
    return mt_rand($min, $max); // random_int($min, $max); // <-- PHP7+
};

var_dump(
    $dynamic->randomInt(1, 11),
    $dynamic->anotherMethod(),
    $dynamic->hisMethod()
);

?>
Ashley Dambra 19-Feb-2014 06:43
Here a simple class that allow to set anonymous function. It's an optimised class of stdClass.

<?php
class stdObject {
    public function __construct(array $arguments = array()) {
        if (!empty($arguments)) {
            foreach ($arguments as $property => $argument) {
                if ($argument instanceOf Closure) {
                    $this->{$property} = $argument;
                } else {
                    $this->{$property} = $argument;
                }
            }
        }
    }

    public function __call($method, $arguments) {
        if (isset($this->{$method}) && is_callable($this->{$method})) {
            return call_user_func_array($this->{$method}, $arguments);
        } else {
            throw new Exception("Fatal error: Call to undefined method stdObject::{$method}()");
        }
    }
}

$person = new stdObject(array(
    "name" => "nick",
    "age" => 23,
    "friends" => array("frank", "sally", "aaron"),
    "sayHi" => function() {
        return "Hello there";
    }
));

$person->sayHi2 = function() {
    return "Hello there 2";
};

$person->test = function() {
    return "test";
};

var_dump($person->name, $person->test(), $person->sayHi2());
?>
wyattstorch42 at outlook dot com 24-Dec-2013 01:15
If you call var_export() on an instance of stdClass, it attempts to export it using ::__set_state(), which, for some reason, is not implemented in stdClass.

However, casting an associative array to an object usually produces the same effect (at least, it does in my case). So I wrote an improved_var_export() function to convert instances of stdClass to (object) array () calls. If you choose to export objects of any other class, I'd advise you to implement ::__set_state().

<?php
/**
 * An implementation of var_export() that is compatible with instances
 * of stdClass.
 * @param mixed $variable The variable you want to export
 * @param bool $return If used and set to true, improved_var_export()
 *     will return the variable representation instead of outputting it.
 * @return mixed|null Returns the variable representation when the
 *     return parameter is used and evaluates to TRUE. Otherwise, this
 *     function will return NULL.
 */
function improved_var_export ($variable, $return = false) {
    if ($variable instanceof stdClass) {
        $result = '(object) '.improved_var_export(get_object_vars($variable), true);
    } else if (is_array($variable)) {
        $array = array ();
        foreach ($variable as $key => $value) {
            $array[] = var_export($key, true).' => '.improved_var_export($value, true);
        }
        $result = 'array ('.implode(', ', $array).')';
    } else {
        $result = var_export($variable, true);
    }

    if (!$return) {
        print $result;
        return null;
    } else {
        return $result;
    }
}

// Example usage:
$obj = new stdClass;
$obj->test = 'abc';
$obj->other = 6.2;
$obj->arr = array (1, 2, 3);

improved_var_export((object) array (
    'prop1' => true,
    'prop2' => $obj,
    'assocArray' => array (
        'apple' => 'good',
        'orange' => 'great'
    )
));

/* Output:
(object) array ('prop1' => true, 'prop2' => (object) array ('test' => 'abc', 'other' => 6.2, 'arr' => array (0 => 1, 1 => 2, 2 => 3)), 'assocArray' => array ('apple' => 'good', 'orange' => 'great'))
*/
?>

Note: This function spits out a single line of code, which is useful to save in a cache file to include/eval. It isn't formatted for readability. If you want to print a readable version for debugging purposes, then I would suggest print_r() or var_dump().
spark at limao dot com dot br 15-Aug-2011 02:21
if you want a Dynamic class you can extend from, add atributes AND methods on the fly you can use this:
<?php
    class Dynamic extends stdClass{
        public function __call($key,$params){
            if(!isset($this->{$key})) throw new Exception("Call to undefined method ".get_class($this)."::".$key."()");
            $subject = $this->{$key};
            call_user_func_array($subject,$params);
        }
    }
?>

this will accept both arrays, strings and Closures:
<?php
    $dynamic->myMethod = "thatFunction";
    $dynamic->hisMethod = array($instance,"aMethod");
    $dynamic->newMethod = array(SomeClass,"staticMethod");
    $dynamic->anotherMethod = function(){
        echo "Hey there";
    };
?>

then call them away =D
Typer85 at gmail dot com 17-Feb-2007 08:58
In response to the note below mine,

This list is not incomplete. Read the Manual folks, its listed there plain and simple:

"This section lists standard predefined classes. Miscellaneous extensions define other classes which are described in their reference."

Depending on what extensions you have, they might define their own classes. This list is just the standard classes as defined by PHP with no regards to extensions.
unknown 23-Jul-2002 10:29
It's handy to have a array of the reserved classes.....
var_dump (get_declared_classes ());

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