责任链模式实现规则校验

1、项目中责任链模式实战
我们使用责任链模式实现对订单中参数的校验，首先校验订单id是否为空，然后校验下单人是否为空，最后检验收获地址是否为空。业务的流程图如下所示：
在这里插入图片描述
针对上述的业务，我们使用责任链的模式来实现这个功能：
（1）定义一个责任链的接口

java">public interface OrderCheckHandler {
	/**
	 * 当前的订单检测实现逻辑
	 * @param orderCheckParam
	 */
	void check(OrderCheckParam orderCheckParam);

	/**
	 * 设置下一个检测的实现逻辑
	 * @param nextOrderCheckHandler
	 * @return
	 */
	OrderCheckHandler setNext(OrderCheckHandler nextOrderCheckHandler);
}

（2）责任链中的公共逻辑的抽取

java">public abstract class BaseCheckOrderHandler implements OrderCheckHandler {
    private OrderCheckHandler nextOrderCheckHandler;
    @Override
    public void check(OrderCheckParam orderCheckParam) {
        this.currentCheck(orderCheckParam);
        if(Objects.nonNull(nextOrderCheckHandler)){
            nextOrderCheckHandler.check(orderCheckParam);
        }
    }
    /**
     * 具体的实现逻辑
     *
     */
    protected abstract void currentCheck(OrderCheckParam orderCheckParam);
    @Override
    public OrderCheckHandler setNext(OrderCheckHandler nextOrderCheckHandler) {
        this.nextOrderCheckHandler = nextOrderCheckHandler;
        return this.nextOrderCheckHandler;
    }
}

（3）具体的检验逻辑（继承公共逻辑）

java">-- 订单id校验
public class OrderIdCheckHandler extends BaseCheckOrderHandler {
	@Override
	protected void currentCheck(OrderCheckParam orderCheckParam) {
        if(orderCheckParam.getOrderId() == null){
            throw new RuntimeException("订单id为空");
        }
	}
}
-- 用户校验
public class BuyerCheckHandler extends BaseCheckOrderHandler {
	@Override
	protected void currentCheck(OrderCheckParam orderCheckParam) {
        if(orderCheckParam.getBuyer() == null){
            throw new RuntimeException("用户不可以为空");
        }
	}
}
-- 地址校验
public class AddressCheckHandler extends BaseCheckOrderHandler {
	@Override
	protected void currentCheck(OrderCheckParam orderCheckParam) {
        if(orderCheckParam.getAddress() == null){
            throw new RuntimeException("用户地址不可以为空");
        }
	}
}

（4）使用spring将业务逻辑串联起来

java">@Configuration
public class OrderCheckConfig {
	@Bean
    public BuyerCheckHandler buyerCheckHandler(){
        return new BuyerCheckHandler();
    }

    @Bean
    public OrderIdCheckHandler checkOrderIdHandler(){
        return new OrderIdCheckHandler();
    }

    @Bean
    public AddressCheckHandler addressCheckHandler(){
        return new AddressCheckHandler();
    }

    //设置责任链得执行链路顺序
    @Bean
    public OrderCheckHandler orderCheckHandler(){
        OrderIdCheckHandler orderIdCheckHandler = this.checkOrderIdHandler();
        orderIdCheckHandler.setNext(this.buyerCheckHandler()).setNext(this.addressCheckHandler());
        return orderIdCheckHandler;
    }
}

（5）service调用责任链的

java">@Service
public class OrderService {

    @Resource
    private OrderCheckHandler orderCheckHandler;

    public String checkOrderParam(OrderCheckParam param){
        orderCheckHandler.check(param);
        return "success";
    }
}

（6）controller逻辑

java">@RestController
@RequestMapping("/test")
public class ZeRenLianTestController {

    @Resource
    private OrderService orderService;

    @GetMapping("/checkOrder")
    public String checkOrder(){
        OrderCheckParam orderCheckParam = new OrderCheckParam();
        orderCheckParam.setAddress("123");
        orderCheckParam.setOrderId("1235689");
        return orderService.checkOrderParam(orderCheckParam);
    }
}