观察者模式

来源：互联网发布：java 正态分布随机数编辑：程序博客网时间：2024/05/22 04:31

1.用js实现观察者模式

<!DOCTYPE html><html><head><title></title><style type="text/css">div{width: 100px;height: 100px;border: 1px #999 solid;margin-bottom: 5px;}</style></head><body><!-- 我们让div对象观察select的变化，selecte变化就会通知这个2个对象，并引起这2个对象的变化，实现观察者模式。 --> <h1>用观察者模式切换页面风格</h1> <select> <option value="male">男式风格</option> <option value="female">女士风格</option> </select> <button onclick="t1()">观察学习区</button>  <button onclick="t2()">不观察学习区</button> <div id="content">我是内容</div> <div id="ad">我是广告</div> <div id="study">学习</div></body><script type="text/javascript">var sel = document.getElementsByTagName('select')[0];sel.observers = {};sel.attach = function(key,obj){this.observers[key] = obj;}sel.detach = function(key){delete this.observers[key];}sel.onchange = sel.notify = function(){for(var key in this.observers){this.observers[key].update(this);}} //客户端var content = document.getElementById('content');var ad = document.getElementById('ad');content.update = function(ob){if (ob.value == 'male') {this.style.backgroundColor = 'gray';}else if(ob.value == 'female'){this.style.backgroundColor = 'pink';}}ad.update = function(ob){if (ob.value == 'male') {this.innerHTML = '汽车';}else if(ob.value == 'female'){this.innerHTML = '减肥';}}//让content观察select的变化sel.attach('content',content);sel.attach('ad',ad);//新增监听study区var study = document.getElementById('study');study.update = function(ob){if (ob.value == 'male') {this.innerHTML = '学习计算机';}else if(ob.value == 'female'){this.innerHTML = '学习美容';}}sel.attach('study',study);function t1(){sel.attach('study',study);}function t2(){sel.detach('study');}</script></html>

2.用php实现观察模式

<?php//php实现观察者//php5中提供观察者observer和被观察者subject的接口class User implements SplSubject{public $lognum;public $hobby;protected $observers = null;public function __construct($hobby){$this->lognum = rand(1,10);$this->hobby = $hobby;$this->observers = new SplObjectStorage();}public function login(){//操作session等$this->notify();}public function attach(SPLObserver $observer){$this->observers->attach($observer);}public function detach(SPLObserver $observer){$this->observers->detach($observer);}public function notify(){$this->observers->rewind();while ($this->observers->valid()) {$observer = $this->observers->current();$observer->update($this);$this->observers->next();}}}//用户安全登录模块class Safe implements SPLObserver{public function update(SplSubject $subject){if ($subject->lognum < 3) {echo '这是第' . $subject->lognum . '次安全登录<br>';}else{echo '这是第' . $subject->lognum . '次登录，异常<br>';}}}//广告模块class Ad implements SPLObserver{public function update(SplSubject $subject){if ($subject->hobby == 'sports') {echo '英超开始啦<br>';}else{echo '好好学习<br>';}}}//实施观察// $user = new User('sports');$user = new User('study');$user->attach(new Safe());$user->attach(new Ad());$user->login();//登录

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