代码过程：
复制代码
package com.sy.homework4;
public class Item {
private String name; // 商品名称
private double price; // 商品价格
private int count; // 商品数量
// 计算总价
public double total(){
return price * count;
}
public Item() {
}
public Item(String name, double price, int count) {
this.name = name;
this.price = price;
this.count = count;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
public int getCount() {
return count;
}
public void setCount(int count) {
this.count = count;
}
@Override
public String toString() {
return "Item{" +
", name='" + name + '\'' +
", price=" + price +
", count=" + count +
'}';
}
}
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package com.sy.homework4;
import java.util.List;
public class Order {
private String orderId; //订单编号
private String userId; //用户ID
private List<Item> items; // 订单中的商品列表
public double amount(){
double total = 0;
for (Item item : items) {
total += item.total();
}
return total;
}
public Order(String o001, String u001, Item 手机, Item 电脑) {
}
public Order(String orderId, String userId, List<Item> items) {
this.orderId = orderId;
this.userId = userId;
this.items = items;
}
public String getOrderId() {
return orderId;
}
public void setOrderId(String orderId) {
this.orderId = orderId;
}
public String getUserId() {
return userId;
}
public void setUserId(String userId) {
this.userId = userId;
}
public List<Item> getItems() {
return items;
}
public void setItems(List<Item> items) {
this.items = items;
}
@Override
public String toString() {
return "Order{" +
"orderId='" + orderId + '\'' +
", userId='" + userId + '\'' +
", items=" + items +
'}';
}
}
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package com.sy.homework4;
import java.util.*;
public class Test {
public static void main(String[] args) {
List<Order> list = new ArrayList<>();
//订单U001
list.add(new Order("O001", "U001", Arrays.asList(
new Item("手机", 5999, 1),
new Item("电脑", 9999, 1))));
list.add(new Order("O002", "U002", Arrays.asList(
new Item("耳机", 199, 1))));
//订单U002
list.add(new Order("O003", "U002", Arrays.asList(
new Item("鼠标", 199, 1),
new Item("键盘", 288, 1))));
list.add(new Order("O004", "U001", Arrays.asList(
new Item("鼠标垫", 59, 1))));
Map<String, List<Order>> map = new HashMap<>();
//遍历所有订单
for (Object o : list) {
Order order = (Order) o;
String userId = order.getUserId();
if (!map.containsKey(userId)) {
map.put(userId, new ArrayList<>());
}
map.get(userId).add(order);
}
System.out.println("========用户消费统计========");
HashMap<String, Double> hashMap = new HashMap<>();
for (Map.Entry<String, List<Order>> entry : map.entrySet()) {
String userId = entry.getKey();
List<Order> orders = entry.getValue();
double total = 0;
for (Order order : orders) {
total += order.amount();
}
hashMap.put(userId, total);
System.out.println("用户" + userId + " 总消费了" + total);
}
//统计总消费
double totals = 0;
for (double s : hashMap.values()) {
totals += s;
}
System.out.println("全平台总营业额：" + totals);
//统计销量最高的商品
Map<String, Integer> map1 = new HashMap<>();
for (Order order : list) {
for (Item item : order.getItems()) {
String name = item.getName();
int count = item.getCount();
if (map1.containsKey(name)){
map1.put(name,map1.get(name) + count);
}else {
map1.put(name,count);
}
}
}
//找出销量最高的商品
String maxName = null;
int maxCount = 0;
for (Map.Entry<String, Integer> entry : map1.entrySet()) {
if (entry.getValue() > maxCount){
maxName = entry.getKey();
maxCount = entry.getValue();
}
}
System.out.println("销量最高的商品是：" + maxName + " 数量是：" + maxCount);
}
}
代码过程：
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package com.sy.homework5;
import java.util.Objects;
public abstract class Vehicle {
private String license; //车牌
private String brand; // 品牌
public abstract String getType();
public Vehicle() {
}
public Vehicle(String license, String brand) {
if (license == null || license.isBlank()) {
throw new IllegalArgumentException("车牌号不能为空！");
}
this.license = license;
this.brand = brand;
}
public String getLicense() {
return license;
}
public void setLicense(String license) {
this.license = license;
}
public String getBrand() {
return brand;
}
public void setBrand(String brand) {
this.brand = brand;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Vehicle vehicle = (Vehicle) o;
return Objects.equals(license, vehicle.license) && Objects.equals(brand, vehicle.brand);
}
@Override
public int hashCode() {
return Objects.hash(license, brand);
}
@Override
public String toString() {
return "Vehicle{" +
"license='" + license + '\'' +
", brand='" + brand + '\'' +
'}';
}
}
复制代码
package com.sy.homework5;
public class Bus extends Vehicle{
public Bus(String license, String brand) {
super(license, brand);
}
@Override
public String getType() {
System.out.println("公交");
return null;
}
}
复制代码
package com.sy.homework5;
public class Car extends Vehicle{
public Car(String license, String brand) {
super(license, brand);
}
@Override
public String getType() {
System.out.println("轿车");
return null;
}
}
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package com.sy.homework5;
public class Truck extends Vehicle{
public Truck(String license, String brand) {
super(license, brand);
}
@Override
public String getType() {
System.out.println("卡车");
return null;
}
}
复制代码
package com.sy.homework5;
import java.util.*;
public class Test {
public static void main(String[] args) {
ArrayList<Vehicle> list = new ArrayList<>();
list.add(new Car("京C00001", "特斯拉"));
list.add(new Car("京A12345", "比亚迪"));
list.add(new Bus("京B67890", "宇通"));
list.add(new Truck("京D54321", "福田"));
list.add(new Car("京C00001", "特斯拉"));
list.add(new Car("", "比亚迪"));
Set<Vehicle> vehicleSet = new LinkedHashSet<>(list);
List<Vehicle> vehicles = new ArrayList<>(vehicleSet);
Map<String, List<Vehicle>> typeMap = new HashMap<>();
for (Vehicle v : list) {
String type = v.getType();
if (!typeMap.containsKey(type)) {
typeMap.put(type, new ArrayList<>());
}
typeMap.get(type).add(v);
}
// 打印按车型分组结果
System.out.println("=====按车型分组=====");
for (Map.Entry<String, List<Vehicle>> entry : typeMap.entrySet()) {
System.out.println(entry.getKey() + ": " + entry.getValue());
}
// 5. 筛选品牌为"比亚迪"的车辆
System.out.println("=====比亚迪车辆=====");
List<Vehicle> bydVehicles = new ArrayList<>();
for (Vehicle v : vehicles) {
if ("比亚迪".equals(v.getBrand())) {
bydVehicles.add(v);
}
}
for (Vehicle v : bydVehicles) {
System.out.println(v);
}
}
}