java/W3/TestCar.java

package com.rental;

public class TestCar {
    public static void main(String[] args) {
        // 创建3辆车
        Car car1 = new Car("京A12345", "丰田", "凯美瑞", 500.0);
        Car car2 = new Car("沪B67890", "大众", "帕萨特");
        Car car3 = new Car("粤C54321", "宝马", "3系", 800.0);

        // 输出车辆信息
        System.out.println("=====车辆信息=====");
        car1.displayInfo();
        car2.displayInfo();
        car3.displayInfo();

        // 测试租车还车
        System.out.println("=====租赁测试=====");
        car1.rentCar();
        car1.rentCar();
        car1.returnCar();
        car1.returnCar();

        // 计算5天租金
        System.out.println("\n=====5天租金=====");
        double money = car3.calculateRent(5);
        System.out.println("5天总租金：" + money);

        // 测试非法租金
        System.out.println("\n=====测试非法日租金=====");
        car2.setDailyRent(-100);

        // 车辆总数
        System.out.println("\n=====总车辆数=====");
        System.out.println("总车辆数：" + Car.getTotalCars());
    }
}

// Car 类写在同一个文件里
class Car {
    private final String licensePlate;
    private String brand;
    private String model;
    private double dailyRent;
    private boolean isRented;

    private static int totalCars = 0;

    // 全参构造
    public Car(String licensePlate, String brand, String model, double dailyRent) {
        this.licensePlate = licensePlate;
        this.brand = brand;
        this.model = model;
        if (dailyRent > 0) {
            this.dailyRent = dailyRent;
        } else {
            this.dailyRent = 300;
            System.out.println("日租金非法，使用默认300元");
        }
        this.isRented = false;
        totalCars++;
    }

    // 三参构造
    public Car(String licensePlate, String brand, String model) {
        this(licensePlate, brand, model, 300.0);
    }

    public String getLicensePlate() {
        return licensePlate;
    }

    public String getBrand() {
        return brand;
    }

    public void setBrand(String brand) {
        this.brand = brand;
    }

    public String getModel() {
        return model;
    }

    public void setModel(String model) {
        this.model = model;
    }

    public double getDailyRent() {
        return dailyRent;
    }

    public void setDailyRent(double dailyRent) {
        if (dailyRent > 0) {
            this.dailyRent = dailyRent;
        } else {
            System.out.println("设置失败：日租金必须大于0");
        }
    }

    public boolean isRented() {
        return isRented;
    }

    public void rentCar() {
        if (isRented) {
            System.out.println("车辆已租出，无法再次租用");
        } else {
            isRented = true;
            System.out.println("租车成功");
        }
    }

    public void returnCar() {
        if (!isRented) {
            System.out.println("车辆未被租用，无需归还");
        } else {
            isRented = false;
            System.out.println("还车成功");
        }
    }

    public double calculateRent(int days) {
        return dailyRent * days;
    }

    public void displayInfo() {
        System.out.println("车牌号：" + licensePlate);
        System.out.println("品牌：" + brand);
        System.out.println("型号：" + model);
        System.out.println("日租金：" + dailyRent);
        System.out.println("状态：" + (isRented ? "已租出" : "可租"));
        System.out.println("-------------------");
    }

    public static int getTotalCars() {
        return totalCars;
    }
}