PHP策略模式demo

<?php
//策略模式就是你有很多的方法,选择一种适合自己的,
//    单例模式就是只有一个实例对象,不需要每个文件都要加载,比如连接数据库,
//    工厂模式就是
//策略模式
interface chargeStrategy{//抽象策略类
    public function charge();
}
class Apicharge implements chargeStrategy{//具体策略类
    public function charge(){
        echo "支付宝支付";
    }
}
class Wxcharge implements chargeStrategy{
    public function charge(){
          echo "微信支付";
    }
}

class pzhang{
    private $charge;
//    public function __construct(ChargeStrategy $chargeStrategy){
//        $this->charge = $chargeStrategy;
//    }
    public function payment($channel){
        if($channel == 'Apicharge'){
            $this->charge = new Apicharge();
        }else if($channel == 'Wxcharge'){
            $this->charge = new Wxcharge();
        }else{
            $this->charge = null;
        }
    }
    public function charge(){
        if(is_null($this->charge)){
            exit('00');
        }
        $this->charge->charge();
    }
}
//$channel = trim($_GET['channel']);
$obj = new pzhang();
$obj->payment('Apicharge');
$obj->charge();
?>