php閉包使用例子

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一.依據閉包實現一個容器

class Di{    private $factory;    public function set($id, $value)    {        $this->factory[$id] = $value;    }    public function get($id)    {        $val = $this->factory[$id];        return $val();//如果不加括弧,僅僅返回的是閉包類,並不是User執行個體    }}class User{    private $username;    public function __construct($username = ‘‘)    {        $this->username = $username;    }    public function getUserName()    {        return $this->username;    }}$di = new Di();// 在此使用了閉包,所以實際上並不會執行個體化User類,只有在後面get的時候才會執行個體化$di->set(‘a‘, function(){    return new User(‘張三‘);});var_dump($di->get(‘a‘)->getUserName());

　　

二.使用閉包作為回調

class Cart{    CONST PRICE_BUTTER = 1.0;    CONST PRICE_MILK = 5.05;    protected $products = [];    public function add($product, $quantity)    {        $this->products[$product] = $quantity;    }    public function getQuantity($product)    {        return isset($this->products[$product]) ? $this->products[$product]: false;    }    public function getTotal($tax)    {        $total = 0.00;        $callback = function($quantity, $product) use ($tax, &$total) {            $priceItem = constant(__CLASS__ . ‘::PRICE_‘ . strtoupper($product));            $total += ($priceItem * $quantity) * ($tax + 1.0);        };        array_walk($this->products, $callback);        return round($total, 2);    }}$cart = new Cart();$cart->add(‘butter‘, 1);$cart->add(‘milk‘, 5);echo $cart->getTotal(0.05);

　　

 

php閉包使用例子