Map里遇到的小坑,掉进去两次

Posted 2021-08-27 醉酒的小男人

这是最近遇到的开发需求,调用了两个RPC,一个是查询订单商品的接口,一个是查询佣金的接口(支持批量),先查询订单商品,再按订单编号查询佣金,存在分页的情况。为了优化代码提高查询效率,先批量按订单号查询了佣金存入了Map<订单号,Map<SKU编号,佣金>>。一个SKU商品存在多个佣金,因为商品存在不同状态。比如买了以后发生退货、换货等。

package utils;
import java.math.BigDecimal;
import java.util.*;
import java.util.stream.Collectors;

public class MapTest {
    public static void main(String[] args) {

        List<Order> orderList = getOrderList();
        Map<Integer,Map<Integer,Optional<BigDecimal>>> orderMap  = new HashMap<>();
        for (Order order : orderList){
            Map<Integer,Optional<BigDecimal>> skuMap = order.getOrderSkuList().stream().collect(Collectors.groupingBy(OrderSku::getSkuId,Collectors.mapping(OrderSku::getCommission,Collectors.reducing(BigDecimal::add))));
            orderMap.put(order.getOrderId(),skuMap);
        }

        String orderId = "1";
        Map<Integer,Optional<BigDecimal>> sku = orderMap.get(orderId);


    }

    public static List<Order> getOrderList(){
        List<Order> orderList = new ArrayList<>();
        Order order1 = new Order(1,new BigDecimal("1.0"));
        List<OrderSku> orderSkuList1 = new ArrayList<>();
        OrderSku orderSku1 = new OrderSku(1001,1,new BigDecimal(1.2));
        OrderSku orderSku2 = new OrderSku(1001,1,new BigDecimal(-1));
        orderSkuList1.add(orderSku1);
        orderSkuList1.add(orderSku2);
        order1.setOrderSkuList(orderSkuList1);

        Order order2 = new Order(2,new BigDecimal("2.0"));
        List<OrderSku> orderSkuList2 = new ArrayList<>();
        OrderSku orderSku3 = new OrderSku(2001,1,new BigDecimal(1.2));
        OrderSku orderSku4 = new OrderSku(2002,1,new BigDecimal(-1));
        orderSkuList2.add(orderSku3);
        orderSkuList2.add(orderSku4);
        order2.setOrderSkuList(orderSkuList2);

        Order order3 = new Order(3,new BigDecimal("3.0"));
        List<OrderSku> orderSkuList3 = new ArrayList<>();
        OrderSku orderSku5 = new OrderSku(3001,1,new BigDecimal(1.2));
        OrderSku orderSku6 = new OrderSku(3002,1,new BigDecimal(-1));
        orderSkuList3.add(orderSku5);
        orderSkuList3.add(orderSku6);
        order3.setOrderSkuList(orderSkuList3);
        orderList.add(order1);
        orderList.add(order2);
        orderList.add(order3);
        return orderList;
    }
}

坑在这里

这里面什么类型都可以往里面放,往往不小心就会掉坑里了

BigDecimal四舍五入看这里