- 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)
这些设计模式在常见的php框架:ThinkPHP, Yii2等都有用到.
/* ?* 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() { ???????$this->db->close(); ???}}single::getInstance();single::getInstance();//输出:/* ???mysql connect successful ???aaa ???bbb ???bbb*//** * 工厂模式 * 用工厂方法代替new操作的一种模式 */interface people{ ???public function say();}class man implements people{ ???public function say() { ???????echo "i am man \n"; ???}}class woman implements people{ ???public function say() { ???????echo "i am woman \n"; ???}}class factory{ ???public function createMan(){ ???????return new man(); ???} ???public function createWoman(){ ???????return new woman(); ???}}$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::working ???bicyle::working ???car::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::run e2::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‘);php常用设计模式
原文地址：https://www.cnblogs.com/kaykay012/p/9599355.html