本文实例讲述了PHP设计模式之观察者模式定义与用法。分享给大家供大家参考，具体如下：

<?php/** * Interface Observable * define a observable interface * @author jichao.wang */interface Observable{ function attach(Observer $observer); function detach(Observer $observer); function notify();}/** * Class Login * @author jichao.wang */class Login implements Observable{ private $observers; public $status; public $ip; const LOGIN_ACCESS = 1; const LOGIN_WRONG_PASS = 2; const LOGIN_USER_UNKNOWN = 3; function __construct() { $this->observers = array(); } /** * @param Observer $observer * @author jichao.wang * attach a observer */ function attach(Observer $observer) { $this->observers[] = $observer; } /** * @param Observer $observer * @author jichao.wang * detach a observer */ function detach(Observer $observer) { $newObservers = array(); foreach ($this->observers as $key => $obs) { if ($obs !== $observer) { $newObservers[] = $obs; } } $this->observers = $newObservers; } /** * @author jichao.wang * handle observer notify */ function notify() { foreach ($this->observers as $obs) { $obs->update($this); } } /** * @author jichao.wang * 执行登陆 */ function handleLogin() { $ip = rand(1,100); switch (rand(1, 3)) { case 1: $this->setStatus(self::LOGIN_ACCESS, $ip); $ret = true; break; case 2: $this->setStatus(self::LOGIN_WRONG_PASS, $ip); $ret = false; break; case 3: $this->setStatus(self::LOGIN_USER_UNKNOWN, $ip); $ret = false; break; } /** * handle event */ $this->notify(); return $ret; } /** * @param $status * @author jichao.wang * set login status */ function setStatus($status,$ip) { $this->status = $status; $this->ip = $ip; } /** * @return mixed * @author jichao.wang * get login status */ function getStatus() { return $this->status; }}/** * Interface Observer * @author jichao.wang */interface Observer { function update(Observable $observable);}/** * Class EmailObserver * @author jichao.wang */class EmailObserver implements Observer { function update (Observable $observable) { $status = $observable->getStatus(); if($status == Login::LOGIN_ACCESS){// $this->sendMail('用户ip:'.$observable->ip.'登陆成功!'); echo __CLASS__.'用户ip:'.$observable->ip.'登陆成功!'.'------------------'; } if($status == Login::LOGIN_WRONG_PASS){// $this->sendMail('用户ip:'.$observable->ip.'登陆失败，密码错误!'); echo __CLASS__.'用户ip:'.$observable->ip.'登陆失败，密码错误!'.'------------------'; } if($status == Login::LOGIN_USER_UNKNOWN){// $this->sendMail('用户ip:'.$observable->ip.'登陆失败，无此用户!'); echo __CLASS__.'用户ip:'.$observable->ip.'登陆失败，无此用户!'.'------------------'; } }}/** * Class PhoneObserver * @author jichao.wang */class PhoneObserver implements Observer { function update (Observable $observable) { $status = $observable->getStatus(); if($status == Login::LOGIN_ACCESS){// $this->sendMail('用户ip:'.$observable->ip.'登陆成功!'); echo __CLASS__.'用户ip:'.$observable->ip.'登陆成功!'.'------------------'; } if($status == Login::LOGIN_WRONG_PASS){// $this->sendMail('用户ip:'.$observable->ip.'登陆失败，密码错误!'); echo __CLASS__.'用户ip:'.$observable->ip.'登陆失败，密码错误!'.'------------------'; } if($status == Login::LOGIN_USER_UNKNOWN){// $this->sendMail('用户ip:'.$observable->ip.'登陆失败，无此用户!'); echo __CLASS__.'用户ip:'.$observable->ip.'登陆失败，无此用户!'.'------------------'; } }}class AbcObserver implements Observer { function update (Observable $observable) { $status = $observable->getStatus(); if($status == Login::LOGIN_ACCESS){// $this->sendMail('用户ip:'.$observable->ip.'登陆成功!'); echo __CLASS__.'用户ip:'.$observable->ip.'登陆成功!'.'------------------'; } if($status == Login::LOGIN_WRONG_PASS){// $this->sendMail('用户ip:'.$observable->ip.'登陆失败，密码错误!'); echo __CLASS__.'用户ip:'.$observable->ip.'登陆失败，密码错误!'.'------------------'; } if($status == Login::LOGIN_USER_UNKNOWN){// $this->sendMail('用户ip:'.$observable->ip.'登陆失败，无此用户!'); echo __CLASS__.'用户ip:'.$observable->ip.'登陆失败，无此用户!'.'------------------'; } }}//实例化登陆信息$login = new Login();//实现发邮件观察者$login->attach(new EmailObserver());//实现发验证码观察者$login->attach(new PhoneObserver());//实现其他观察者$login->attach(new AbcObserver());//开始登陆$login->handleLogin();?>

运行结果：

EmailObserver用户ip:41登陆失败，无此用户!------------------PhoneObserver用户ip:41登陆失败，无此用户!------------------AbcObserver用户ip:41登陆失败，无此用户!------------------

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希望本文所述对大家PHP程序设计有所帮助。