对象方法PHP中魔术方法的用法对象方法
新手发帖，很多方面都是刚入门，有错误的地方请大家见谅，欢迎批评指正
/** PHP把全部以__（两个下划线）头开的类方法成当术魔方法。所以你义定自己的类方法时，不要以 __为前缀。 * */
// __toString、__set、__get__isset()、__unset()
/*
The __toString method allows a class to decide how it will react when it is converted to a string.
__set() is run when writing data to inaccessible members.
__get() is utilized for reading data from inaccessible members.
__isset() is triggered by calling isset() or empty() on inaccessible members.
__unset() is invoked when unset() is used on inaccessible members.
*/
class TestClass {
private $data = array();
public $foo;
public function __construct($foo) {
$this->foo = $foo;
}
public function __toString() {
return $this->foo;
}
public function __set($name, $value) {
echo "__set, Setting '$name' to '$value'\n";
$this->data[$name] = $value;
}
public function __get($name) {
echo "__get, Getting '$name'\n";
if (array_key_exists($name, $this->data)) {
return $this->data[$name];
}
}
/** As of PHP 5.1.0 */
public function __isset($name) {
echo "__isset, Is '$name' set?\n";
return isset($this->data[$name]);
}
/** As of PHP 5.1.0 */
public function __unset($name) {
echo "__unset, Unsetting '$name'\n";
unset($this->data[$name]);
}
}
$obj = new TestClass('Hello');
echo "__toString, $obj\n";
$obj->a = 1;
echo $obj->a . "\n\n";
var_dump(isset($obj->a));
unset($obj->a);
var_dump(isset($obj->a));
echo "\n\n";
/**
输出结果如下：
__toString, Hello
__set, Setting 'a' to '1'
__get, Getting 'a'
__isset, Is 'a' set?
bool(true)
__unset, Unsetting 'a'
__isset, Is 'a' set?
bool(false)
**/
// __call __callStatic
/*
mixed __call ( string $name , array $arguments )
mixed __callStatic ( string $name , array $arguments )
__call() is triggered when invoking inaccessible methods in an object context.
__callStatic() is triggered when invoking inaccessible methods in a static context.
The $name argument is the name of the method being called.
The $arguments argument is an enumerated array containing the parameters passed to the $name'ed method.
*/
class MethodTest {
public function __call($name, $arguments) {
// Note: value of $name is case sensitive.
echo "__call, Calling object method '$name' " . implode(', ', $arguments) . "\n";
}
/** As of PHP 5.3.0 */
public static function __callStatic($name, $arguments) {
// Note: value of $name is case sensitive.
echo "__callStatic, Calling static method '$name' " . implode(', ', $arguments) . "\n";
}
}
$obj = new MethodTest;
$obj->runTest('in object context', 'param2', 'param3');
//MethodTest::runTest('in static context'); // As of PHP 5.3.0
echo "\n\n";
/**
输出结果如下：
__call, Calling object method 'runTest' in object context, param2, param3
string(10) "__invoke: "
*/
// __invoke
/*
The __invoke method is called when a script tries to call an object as a function.
Note: This feature is available since PHP 5.3.0.
*/
class CallableClass {
function __invoke($x) {
var_dump($x);
}
}
$obj = new CallableClass;
//$obj(5);
var_dump('__invoke: ' . is_callable($obj));
echo "\n\n";
// __sleep __wakeup
/*
串行化serialize可以把量变括包对象,转化成连续bytes数据. 你可以将串行化后的量变存在一个文件里或在网络上传输.
然后再反串行化还原为来原的数据. 你在反串行化类的对象之前义定的类,PHP可以成功地存储其对象的性属和方法.
时有你可能须要一个对象在反串行化后当即执行. 为了这样的目标,PHP会动自寻觅__sleep和__wakeup方法.
当一个对象被串行化,PHP会调用__sleep方法(如果存在的话). 在反串行化一个对象后,PHP 会调用__wakeup方法.
这两个方法都不受接参数. __sleep方法必须返回一个数组,含包须要串行化的性属. PHP会摈弃其它性属的值.
如果没有__sleep方法,PHP将存保全部性属.上面的例子示显了如何用__sleep和__wakeup方法来串行化一个对象.
Id性属是一个不算打保留在对象中的临时性属. __sleep方法保障在串行化的对象中不含包id性属.
当反串行化一个User对象,__wakeup方法建立id性属的新值. 这个例子被计设成自我坚持.
在现实开辟中,你可能发明含包源资(如像图或数据流)的对象须要这些方法
*/
class User {
public $name;
public $id;
function __construct() {
//give user a unique ID 予赋一个别差 的ID
$this->id = uniqid();
}
//__sleep返回值的类型是数组，数组中的值是不须要串型化的段字id
function __sleep() {
//do not serialize this->id 不串行化id
return(array("name"));
}
function __wakeup() {
//give user a unique ID
$this->id = uniqid();
}
}
//create object 立成一个东西
$u = new User;
$u->name = "Leon"; //serialize it 串行化 留心不串行化id性属,id的值被遗弃
$s = serialize($u);
echo "__sleep, __wakeup, s: $s"; //unserialize it 反串行化 id被从新赋值
$u2 = unserialize($s); //$u and $u2 have different IDs $u和$u2有别差 的ID
print_r($u);
print_r($u2);
echo "\n\n";
/**
输出结果如下：
__sleep, __wakeup, s: O:4:"User":1:{s:4:"name";s:4:"Leon";}
User Object
(
[name] => Leon
[id] => 4db1b17640da1
)
User Object
(
[name] => Leon
[id] => 4db1b17640dbc
)
*/
// __set_state
/*
This static method is called for classes exported by var_export() since PHP 5.1.0.
The only parameter of this method is an array containing exported properties in the form array('property' => value, ...).
*/
class A {
public $var1;
public $var2;
public static function __set_state($an_array) { // As of PHP 5.1.0
//$an_array打印出来是数组，而不是调用时递传的对象
print_r($an_array);
$obj = new A;
$obj->var1 = $an_array['var1'];
$obj->var2 = $an_array['var2'];
return $obj;
}
}
$a = new A;
$a->var1 = 5;
$a->var2 = 'foo';
echo "__set_state:\n";
eval('$b = ' . var_export($a, true) . ';');
// $b = A::__set_state(array(
// 'var1' => 5,
// 'var2' => 'foo',
// ));
var_dump($b);
echo "\n\n";
/**
输出结果如下：
__set_state:
Array
(
[var1] => 5
[var2] => foo
)
object(A)#5 (2) {
["var1"]=>
int(5)
["var2"]=>
string(3) "foo"
}
*/
// __clone
class SubObject {
static $instances = 0;
public $instance;
public function __construct() {
$this->instance = ++self::$instances;
}
public function __clone() {
$this->instance = ++self::$instances;
}
}
class MyCloneable {
public $object1;
public $object2;
function __clone() {
// Force a copy of this->object, otherwise
// it will point to same object.
$this->object1 = clone $this->object1;
}
}
$obj = new MyCloneable();
$obj->object1 = new SubObject();
$obj->object2 = new SubObject();
$obj2 = clone $obj;
print("__clone, Original Object:\n");
print_r($obj);
print("__clone, Cloned Object:\n");
print_r($obj2);
echo "\n\n";
/**
输出结果如下：
__clone, Original Object:
MyCloneable Object
(
[object1] => SubObject Object
(
[instance] => 1
) [object2] => SubObject Object
(
[instance] => 2
))
__clone, Cloned Object:
MyCloneable Object
(
[object1] => SubObject Object
(
[instance] => 3
) [object2] => SubObject Object
(
[instance] => 2
))
*/
文章结束给大家分享下程序员的一些笑话语录： 火车
一个年轻的程序员和一个项目经理登上了一列在山里行驶的火车，他们发现 列车上几乎都坐满了，只有两个在一起的空位，这个空位的对面是一个老奶 奶和一个年轻漂亮的姑娘。两个上前坐了下来。程序员和那个姑娘他们比较 暧昧地相互看对方。这时，火车进入山洞，车厢里一片漆黑。此时，只听见 一个亲嘴的声音，随后就听到一个响亮的巴掌声。很快火车出了山洞，他们 四个人都不说话。
那个老奶奶在喃喃道， “这个年轻小伙怎么这么无礼， 不过我很高兴我的孙女 扇了一个巴掌”。
项目经理在想，“没想到这个程序员居然这么大胆，敢去亲那姑娘，只可惜那 姑娘打错了人，居然给打了我。”
漂亮的姑娘想，“他亲了我真好，希望我的祖母没有打疼他”。
程序员坐在那里露出了笑容， “生活真好啊。 这一辈子能有几次机会可以在亲 一个美女的同时打项目经理一巴掌啊”
