设计模式-策略模式

定义一个策略接口

public interface PayStrategy {
    void pay(BigDecimal price);
}

具体策略的实现

public class WxPay implements PayStrategy {
    @Override
    public void pay(BigDecimal price) {
        System.out.println("微信支付" + price + "元");
    }
}

public class ZfbPay implements PayStrategy {
    @Override
    public void pay(BigDecimal price) {
        System.out.println("支付宝支付" + price + "元");
    }
}

策略的入口

public class Mall {

    private PayStrategy payStrategy;
    private BigDecimal price;

    public Mall factory(String payType) {
        if ("WX".equals(payType)) {
            this.payStrategy = new WxPay();
        } else if ("ZFB".equals(payType)) {
            this.payStrategy = new ZfbPay();
        }
        return this;
    }

    public Mall setPrice(BigDecimal price) {
        this.price = price;
        return this;
    }

    public void pay() {
        payStrategy.pay(price);
    }
}

测试

public class Demo {
    public static void main(String[] args) {
        new Mall().factory("WX").setPrice(new BigDecimal(1000)).pay();
        new Mall().factory("ZFB").setPrice(new BigDecimal(2000)).pay();
    }
}