《Head First 设计模式》代码之PHP版(面向对象学习)_php技巧

《Head First 设计模式》是本不错的讲解设计模式的书，不像F4写的那么枯燥，应该算是比较容易理解的好书。

书中的例子都比较浅显易懂，不过由于是外国佬写的，所以例子的习惯不是很附合中国特色，可能偶尔看起来有些别扭，还有语言习惯也不是中国风。当然��看过这本书之后，你才能深刻理解设计模式到底能为你解决哪些问题，不能为你解决哪些问题（比如不能代替你的编码）。
　　我将书中部分代码改成PHP，看下代码再配合概念应该是比较容易理解了。

策略模式

代码如下:

<?php /** * 策略模式 * 定义了算法族，分别封装起来，让它们之间可以互相替换， * 此模式让算法的变化独立于使用算法的客户。 */ //飞行行为接口 interface FlyBehavior { public function fly(); } //呱呱叫行为接口 interface QuackBehavior { public function quack(); } //翅膀飞行 class FlyWithWings implements FlyBehavior { public function fly() { echo "I'm flying!!\n"; } } //不会飞 class FlyNoWay implements FlyBehavior { public function fly() { echo "I can't fly!\n"; } } class FlyRocketPowered implements FlyBehavior { public function fly() { echo "I'm flying with a rocket!\n"; } } class Qquack implements QuackBehavior { public function quack() { echo "Quack\n"; } } class Squeak implements QuackBehavior { public function quack() { echo "Squeak\n"; } } class MuteQuack implements QuackBehavior { public function quack() { echo "<< Silence >>\n"; } } abstract class Duck { protected $quack_obj; protected $fly_obj; public abstract function display(); public function performQuack() { $this->quack_obj->quack(); } public function performFly() { $this->fly_obj->fly(); } public function swim() { echo "All ducks float, even decoys!\n"; } public function setFlyBehavior(FlyBehavior $fb) { $this->fly_obj = $fb; } public function setQuackBehavior(QuackBehavior $qb) { $this->quack_obj = $qb; } } class ModelDuck extends Duck { public function __construct() { $this->fly_obj = new FlyNoWay(); $this->quack_obj = new MuteQuack(); } public function display() { echo "I'm a model duck!\n"; } } $model = new ModelDuck(); $model->performFly(); $model->performQuack(); //提供新的能力 $model->setFlyBehavior(new FlyRocketPowered()); $model->setQuackBehavior(new Squeak()); $model->performFly(); $model->performQuack(); ?>

单件模式

代码如下:

<?php /** * 单件模式 * 确保一个类只有一个实例，并提供一个全局访问点。 */ class MyClass { private static $uniqueInstance; private function __construct() { } public static function getInstance() { if (self::$uniqueInstance == null) { self::$uniqueInstance = new MyClass(); } return self::$uniqueInstance; } } $myClass = MyClass::getInstance(); var_dump($myClass); $myClass = MyClass::getInstance(); var_dump($myClass); ?>

工厂方法模式

代码如下:

<?php abstract class PizzaStore { public function orderPizza($type) { $pizza = $this->createPizza($type); $pizza->prepare(); $pizza->bake(); $pizza->cut(); $pizza->box(); return $pizza; } public abstract function createPizza($type); } class NYPizzaStore extends PizzaStore { public function createPizza($type) { if ($type == "cheese") { return new NYStyleCheesePizza(); } elseif ($type == "veggie") { return new NYStyleVeggiePizza(); } elseif ($type == "clam") { return new NYStyleClamPizza(); } elseif ($type == "papperoni") { return new NYStylePapperoniPizza(); } else { return null; } } } class ChicagoPizzaStore extends PizzaStore { public function createPizza($type) { if ($type == "cheese") { return new ChicagoStyleCheesePizza(); } elseif ($type == "veggie") { return new ChicagoStyleVeggiePizza(); } elseif ($type == "clam") { return new ChicagoStyleClamPizza(); } elseif ($type == "papperoni") { return new ChicagoStylePapperoniPizza(); } else { return null; } } } abstract class Pizza { public $name; public $dough; public $sauce; public $toppings = array(); public function prepare() { echo "Preparing " . $this->name . "\n"; echo "Yossing dough...\n"; echo "Adding sauce...\n"; echo "Adding toppings: \n"; for ($i = 0; $i < count($this->toppings); $i++) { echo " " . $this->toppings[$i] . "\n"; } } public function bake() { echo "Bake for 25 minutes at 350\n"; } public function cut() { echo "Cutting the pizza into diagonal slices\n"; } public function box() { echo "Place pizza in official PizzaStore box\n"; } public function getName() { return $this->name; } } class NYStyleCheesePizza extends Pizza { public function __construct() { $this->name = "NY Style Sauce and cheese Pizza"; $this->dough = "Thin Crust Dough"; $this->sauce = "Marinara Sauce"; $this->toppings[] = "Grated Reggiano Cheese"; } } class NYStyleVeggiePizza extends Pizza { public function __construct() { $this->name = "NY Style Sauce and veggie Pizza"; $this->dough = "Thin Crust Dough"; $this->sauce = "Marinara Sauce"; $this->toppings[] = "Grated Reggiano veggie"; } } class NYStyleClamPizza extends Pizza { public function __construct() { $this->name = "NY Style Sauce and clam Pizza"; $this->dough = "Thin Crust Dough"; $this->sauce = "Marinara Sauce"; $this->toppings[] = "Grated Reggiano clam"; } } class NYStylePapperoniPizza extends Pizza { public function __construct() { $this->name = "NY S<i style="color:transparent">本文来源gaodai$ma#com搞$$代**码)网8</i><strong>搞代gaodaima码</strong>tyle Sauce and papperoni Pizza"; $this->dough = "Thin Crust Dough"; $this->sauce = "Marinara Sauce"; $this->toppings[] = "Grated Reggiano papperoni"; } } class ChicagoStyleCheesePizza extends Pizza { public function __construct() { $this->name = "Chicago Style Deep Dish Cheese Pizza"; $this->dough = "Extra Thick Crust Dough"; $this->sauce = "Plum Tomato Sauce"; $this->toppings[] = "Shredded Mozzarella Cheese"; } public function cut() { echo "Cutting the pizza into square slices\n"; } } $myStore = new NYPizzaStore(); $chicagoStore = new ChicagoPizzaStore(); $pizza = $myStore->orderPizza("cheese"); echo "Ethan ordered a " . $pizza->getName() . "\n"; $pizza = $chicagoStore->orderPizza("cheese"); echo "Ethan ordered a " . $pizza->getName() . "\n"; ?>

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