Java停车罚单模拟器 - 类聚合/复制构造函数

以下是一个使用Java实现的停车罚单模拟器的示例代码，其中使用了类聚合和复制构造函数：

// 定义车辆类
class Vehicle {
    private String licensePlate;
    private String vehicleType;

    // 复制构造函数
    public Vehicle(Vehicle vehicle) {
        this.licensePlate = vehicle.getLicensePlate();
        this.vehicleType = vehicle.getVehicleType();
    }

    public Vehicle(String licensePlate, String vehicleType) {
        this.licensePlate = licensePlate;
        this.vehicleType = vehicleType;
    }

    public String getLicensePlate() {
        return licensePlate;
    }

    public String getVehicleType() {
        return vehicleType;
    }
}

// 定义停车罚单类
class ParkingTicket {
    private Vehicle vehicle;
    private String ticketNumber;

    public ParkingTicket(Vehicle vehicle, String ticketNumber) {
        this.vehicle = new Vehicle(vehicle); // 类聚合，通过复制构造函数创建新的Vehicle对象
        this.ticketNumber = ticketNumber;
    }

    public Vehicle getVehicle() {
        return vehicle;
    }

    public String getTicketNumber() {
        return ticketNumber;
    }
}

// 测试代码
public class ParkingTicketSimulator {
    public static void main(String[] args) {
        // 创建车辆对象
        Vehicle vehicle = new Vehicle("ABC123", "Car");

        // 创建停车罚单对象
        ParkingTicket ticket1 = new ParkingTicket(vehicle, "T001");
        System.out.println("Ticket 1 - License Plate: " + ticket1.getVehicle().getLicensePlate());
        System.out.println("Ticket 1 - Vehicle Type: " + ticket1.getVehicle().getVehicleType());
        System.out.println("Ticket 1 - Ticket Number: " + ticket1.getTicketNumber());

        // 修改原始车辆对象
        vehicle.setLicensePlate("XYZ789");
        vehicle.setVehicleType("Truck");

        // 创建另一个停车罚单对象
        ParkingTicket ticket2 = new ParkingTicket(vehicle, "T002");
        System.out.println("Ticket 2 - License Plate: " + ticket2.getVehicle().getLicensePlate());
        System.out.println("Ticket 2 - Vehicle Type: " + ticket2.getVehicle().getVehicleType());
        System.out.println("Ticket 2 - Ticket Number: " + ticket2.getTicketNumber());
    }
}

上述代码中，Vehicle类表示车辆，拥有车牌号码和车辆类型两个属性。在ParkingTicket类中，使用类聚合的方式将Vehicle对象作为属性，并通过复制构造函数创建一个新的Vehicle对象，从而避免在创建停车罚单时引用同一个车辆对象。在测试代码中，创建了两个停车罚单对象，分别对应不同的车辆信息。