做教育网站的er图/如何做网络营销

• 单例模式 (确保一个类只实例化一次并且可以自行实例化)
• 工厂模式 (替代了new操作)
• 策略模式 (使用不同的方法来达到同样的目的)
• 观察者模式 (一个对象发生变化时其他对象也会触发相应的操作)
• 适配器模式 (把不同的方法封装成统一的方法)
• 注册模式 (把实例放进一个数组以供调用)

/* * 单例模式* 确保此类只有一个实例并可以自行实例化* 用在: 数据库操作, 日志对象 等.*/class single{public $db = NULL;static $instance = null;public function __construct() {        $this->db = new mysqli('127.0.0.1', 'root', 'root', 'test');if($this->db->connect_error){die('connect error:' . $this->db->connect_error);}echo "mysql connect successful\n";}static public function  getInstance(){if(!(self::$instance instanceof self)){self::$instance = new self();echo "aaa\n";}echo "bbb\n";return self::$instance;}public function __destruct() {$this->db->close();}
}single::getInstance();
single::getInstance();//输出:
/*mysql connect successfulaaabbbbbb
*/

/*** 工厂模式* 用工厂方法代替new操作的一种模式*/
interface people{public function say();
}class man implements people{public function say() {echo "i am man \n";}
}class woman implements people{public function say() {echo "i am woman \n";}
}class factory{public function createMan(){return new man();}public function createWoman(){return new woman();}
}$f = new factory();
$f->createMan()->say();
$f->createWoman()->say();//输出
/*i am man i am woman */

/*** 策略模式 [使用不同的方式达到同一个目的]* 场景:乘坐不同交通工具去公司上班*/abstract class tools{abstract function working();
}class bicyle extends tools{public function working() {echo __METHOD__ . "\n";}
}class car extends tools{public function working() {echo __METHOD__ . "\n";}
}class transport{public function running($obj){$obj->working();}/*** 使用魔术方法也可以达到上述效果* @param type $name* @param type $arguments*/public function __call($name, $arguments) {$arguments[0]->$name();}
}$t = new transport();
$t->running(new car());
$t->running(new bicyle());$t->working(new car());//使用魔术方法也可以达到上述效果//输出
/*car::workingbicyle::workingcar::working */

/* * 观察者模式* 当一个对象状态发生变化时,依赖它的对象全部收到触发操作* 发生场景:yii2的behavior,event*/interface event{function run();
}class e1 implements event{public function run() {echo __METHOD__ . "\n";}
}class e2 implements event{public function run() {echo __METHOD__ . "\n";}
}class observer{static $obs;function addObs($name, $obj){self::$obs[$name] = $obj;}function trigger(){foreach (self::$obs as $val){$val->run();}}
}$o = new observer();
$o->addObs('e1', new e1());
$o->addObs('e2', new e2());
$o->trigger();//输出
/*e1::rune2::run */

/* * 适配器模式* 把不同的方法封装成统一的方法以供调用* 用在 数据库 mysql, mysqli, pdo 等*/interface db{public function connect();public function query();public function close();
}class mysqlA implements db{public $db;public function connect(){$this->db = mysqli_connect($host, $user, $password, $database, $port, $socket);}public function query(){}public function close(){mysqli_close($this->db);}
}class mysqlB implements db{public $db;public function connect() {$this->db = new PDO($dsn, $username, $password);}public function query(){}public function close(){$this->db = null;}
}

/* * 注册模式* 把已有对象放入一个数组里以供调用*/class register{static $objects;public static function set($name, $obj){self::$objects[$name] = $obj;}public static function get($name){return self::$objects[$name];}
}class log{};register::set('log', new log());
$log = register::get('log');