java - array List 重复和排序方法

Question

此类捕获订单详细信息。

public class OrderDetails {
private int priceEach = 0;
private int quantityOrdered = 0;
private String productCode = null;

public OrderDetails(int priceEach, int quantityOrdered, String productCode) {
    super();
    this.priceEach = priceEach;
    this.quantityOrdered = quantityOrdered;
    this.productCode = productCode;
}

public int getPriceEach() {
    return this.priceEach;
}

public int getQuantityOrdered() {
    return this.quantityOrdered;
}

public String getProductCode() {
    return this.productCode;
}

此类捕获产品

public class Products {
private String productName = null;
private String productCode = null;

public Products(String productName, String productCode) {
    super();
    this.productName = productName;
    this.productCode = productCode;
}

public String getProductName() {
    return this.productName;
}

public String getProductCode() {
    return this.productCode;
}

}

我需要一种方法来计算按产品名称排序的每个产品产生的收入。请记住，该方法中的数组列表将有重复项，并且以不同的价格定价。该方法的输出应该没有重复项，并且经过排序，每个产品名称都有与其对应的收入。

这是我尝试过的方法，但没有给出正确的输出。该方法位于 Products 类中。

public int calaculateTotalCost(List<OrderDetails> orderDetails, List<Products> products, String productCode,
        String productName) {
    int sum = 0;

    for (OrderDetails o : orderDetails) {
        for (Products p : products)
            if ((o.getProductCode() == productCode) && p.getProductName() == productName) {
                sum += (o.getPriceEach() * o.getQuantityOrdered());
            }

    }

    return sum;
}

Answer 1

你可以尝试这样的事情:

    public Map calaculateTotalCost(List<OrderDetails> orderDetails, List<Products> products) {
        Map<String, Products> map = new LinkedHashMap<>();
        Map<Products, Integer> revenue = new HashMap<>();

        for (Products p : products) {
            map.put(p.getProductCode(), p);
        }

        for (OrderDetails order : orderDetails) {
            if (map.containsKey(order.getProductCode())) {
                Products p = map.get(order.getProductCode());
                revenue.put(p, revenue.getOrDefault(p, 0) + (order.getPriceEach() * order.getQuantityOrdered()));
            }
        }

        return revenue.entrySet().stream().sorted(Entry.<Products, Integer>comparingByValue().reversed())
                .sorted(Entry
                        .<Products, Integer>comparingByKey((p1, p2) -> p1.getProductName().compareTo(p2.productName)))
                .collect(Collectors.toMap(k -> k, v -> v));
    }