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1、__construct():构造方法，当类被实例化new $class时被自动调用的方法，在类的继承中可以继承与覆盖该方法，例：
//__construct() class construct{ public function __construct(){ $this->var = "this is var"; } } class con2 extends construct{ public function __construct(){ $this->var = "this is var2"; } } $con2 = new con2; echo $con2->var;
3、__destruct():当对象销毁或者不再使用时(页面运行完)，自动调用这个方法，例：
class construct{ public function __construct(){ $this->var = "this is var"; } public function __destruct(){ echo ‘close‘; } } $con = new construct; //或者最常用的关闭资源 class destruct{ public function __construct(){ $this->logfile_handle = fopen(‘/tmp/log.txt‘,w); } public function __destruct(){ fclose($this->logfile_handle); } }
4、__toString():该方法用于一个类被当成字符串时应怎么样回应，也就是echo $class时返回的内容是什么，如果没有__toString()魔术方法时，将会返回一个E_RECOVERABLE_ERROR级别的致命错误。
例：
<?php class TestClass{ public $foo; public function __construct($foo){ $this->foo = $foo; } public function __toString(){ return $this->foo; } } $class = new TestClass(‘Hello‘); echo $class;//Hello ?>
5、__invoke():该魔术方法用于类被当作函数使用时，自动调用该方法，但是...__invoke()魔术方法只在PHP5.3.0以上才有效；例
//__invoke() PHP5.3.0以上版本有效 class CallableClass{ function __invoke($x){ var_dump($x); } } $obj = new CallableClass; $obj(5); var_dump(is_callable($obj));//true
6、__get()与__set():从一个难以访问的属性读取数据是自动调用__get()魔术方法，从一个难以访问的熟悉赋值的时候自动调用__set()魔术方法，难以访问包括（私有属性，未定义属性、没有初始化的属性）例：
//__get() __set() class demoClass{ private $a; private function __get($name){ return ‘this var not exist‘; } private function __set($name,$value){ echo ‘this var value not exist‘; } } $demo = new demoClass(); var_dump($demo->a);//调用__get()方法 $demo->a = 1;//调用__set()方法
7、__call():该方法在范围类中不存在的方法时自动调用的方法，参数有两个；例：
//__call() class funClass{ public function __call($name,$arg){ echo $name.‘function not exist‘; } } $fun = new funClass(); $fun->aa();//function not exist
8、__sleep()和__wakeup:这两个魔术方法是在对象序列化serialize()和解序列化unserialize()自动调用的方法：例
//__sleep __wakeup 简单实例 class sleepClass{ public $myContent; public function __construct($string){ $this->myContent = $string; } public function __sleep(){ $this->myContent = "this is mimi"; return array(‘myContent‘); } public function __wakeup(){ echo ‘aaa‘; } } $sleep = new sleepClass(‘i love bb‘); $ser = serialize($sleep);//this is mimi unserialize($ser);//aaa //或者 常用实例 class Connection { protected $link; private $server, $username, $password, $db; public function __construct($server, $username, $password, $db) { $this->server = $server; $this->username = $username; $this->password = $password; $this->db = $db; $this->connect(); } private function connect() { $this->link = mysql_connect($this->server, $this->username, $this->password); mysql_select_db($this->db, $this->link); } public function __sleep() { return array(‘server‘, ‘username‘, ‘password‘, ‘db‘); } public function __wakeup() { $this->connect(); } } $con = new Connection(‘127.0.0.1‘,‘root‘,‘‘,‘mythinkcom‘); echo serialize($con);
9、__clone():$obj2 = clone $obj1与$obj2 = $obj1的区别是前者有两块内存地址，而后者只有一块内存地址。
class cloneClass{ public $var = ‘aa‘; } $clone = new cloneClass; $clone2 = clone $clone; echo $clone->var; echo $clone2->var;
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原文地址：http://www.cnblogs.com/longfeiPHP/p/4987928.html
