第三周实验

CAR/Car.java

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+package com.rental;
+
+/**
+ * 车辆管理系统的Car类，封装车辆属性和业务行为
+ */
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class Car {
+    // 私有属性
+    private final String licensePlate; // 车牌号不可变，加final
+    private String brand;
+    private String model;
+    private double dailyRent;
+    private boolean isRented;
+
+    // 静态变量：统计车辆总数（线程安全）
+    private static final AtomicInteger totalCars = new AtomicInteger(0);
+
+    // 全参构造方法：车牌号、品牌、型号、日租金
+    public Car(String licensePlate, String brand, String model, double dailyRent) {
+        if (licensePlate == null || licensePlate.trim().isEmpty()) {
+            throw new IllegalArgumentException("车牌号不能为空");
+        }
+        if (brand == null || brand.trim().isEmpty()) {
+            throw new IllegalArgumentException("品牌不能为空");
+        }
+        if (model == null || model.trim().isEmpty()) {
+            throw new IllegalArgumentException("型号不能为空");
+        }
+        this.licensePlate = licensePlate.trim();
+        this.brand = brand.trim();
+        this.model = model.trim();
+        this.dailyRent = validateDailyRent(dailyRent);
+        this.isRented = false;
+        totalCars.incrementAndGet();
+    }
+
+    // 三参构造方法：调用全参构造，日租金默认300
+    public Car(String licensePlate, String brand, String model) {
+        this(licensePlate, brand, model, 300.0); // this()必须是构造方法第一行
+    }
+
+    // Getter：车牌号（仅get，无set）
+    public String getLicensePlate() {
+        return licensePlate;
+    }
+
+    // 品牌：get+set
+    public String getBrand() {
+        return brand;
+    }
+    public void setBrand(String brand) {
+        this.brand = brand;
+    }
+
+    // 型号：get+set
+    public String getModel() {
+        return model;
+    }
+    public void setModel(String model) {
+        this.model = model;
+    }
+
+    // 日租金：get+set（含合法性校验）
+    public double getDailyRent() {
+        return dailyRent;
+    }
+    public void setDailyRent(double dailyRent) {
+        this.dailyRent = validateDailyRent(dailyRent);
+    }
+
+    // 私有方法：验证日租金合法性
+    private double validateDailyRent(double dailyRent) {
+        if (dailyRent > 0) {
+            return dailyRent;
+        } else {
+            System.out.println("日租金必须大于0，使用默认值300元/天");
+            return 300.0;
+        }
+    }
+
+    // 租出状态：仅查询（isXXX命名规范），无set
+    public boolean isRented() {
+        return isRented;
+    }
+
+    // 静态方法：获取车辆总数
+    public static int getTotalCars() {
+        return totalCars.get();
+    }
+
+    // 业务方法：租车
+    public boolean rentCar() {
+        if (isRented) {
+            System.out.println("车牌号【" + licensePlate + "】：车辆已租出，无法再次租用");
+            return false;
+        } else {
+            isRented = true;
+            System.out.println("车牌号【" + licensePlate + "】：租车成功，车辆已租出");
+            return true;
+        }
+    }
+
+    // 业务方法：还车
+    public boolean returnCar() {
+        if (!isRented) {
+            System.out.println("车牌号【" + licensePlate + "】：车辆未被租用，无需归还");
+            return false;
+        } else {
+            isRented = false;
+            System.out.println("车牌号【" + licensePlate + "】：还车成功，车辆已归还");
+            return true;
+        }
+    }
+
+    // 业务方法：计算总租金（日租金×天数）
+    public double calculateRent(int days) {
+        if (days <= 0) {
+            throw new IllegalArgumentException("租车天数必须大于0");
+        }
+        return dailyRent * days;
+    }
+
+    // 自定义方法：展示车辆完整信息（方便测试）
+    public void displayInfo() {
+        System.out.println("=====================");
+        System.out.println("车牌号：" + licensePlate);
+        System.out.println("品牌型号：" + brand + "-" + model);
+        System.out.println("日租金：" + dailyRent + "元/天");
+        System.out.println("车辆状态：" + (isRented ? "已租出" : "可租用"));
+        System.out.println("=====================\n");
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        Car car = (Car) o;
+        return Objects.equals(licensePlate, car.licensePlate);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(licensePlate);
+    }
+
+    @Override
+    public String toString() {
+        return "Car{" +
+                "licensePlate='" + licensePlate + '\'' +
+                ", brand='" + brand + '\'' +
+                ", model='" + model + '\'' +
+                ", dailyRent=" + dailyRent +
+                ", isRented=" + isRented +
+                '}';
+    }
+}

CAR/TestCar.java

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+import com.rental.Car;
+
+public class TestCar {
+    public static void main(String[] args) {
+        try {
+            // 测试1：创建车辆对象
+            System.out.println("=== 测试1：创建车辆对象 ===");
+            Car car1 = new Car("沪A12345", "奥迪", "A6", 500.0);
+            Car car2 = new Car("沪B67890", "宝马", "5系"); // 使用默认日租金
+            
+            // 测试2：展示车辆信息
+            System.out.println("=== 测试2：展示车辆信息 ===");
+            car1.displayInfo();
+            car2.displayInfo();
+            
+            // 测试3：租车操作
+            System.out.println("=== 测试3：租车操作 ===");
+            boolean rentResult1 = car1.rentCar();
+            System.out.println("租车结果: " + (rentResult1 ? "成功" : "失败"));
+            
+            // 测试4：重复租车
+            System.out.println("=== 测试4：重复租车 ===");
+            boolean rentResult2 = car1.rentCar();
+            System.out.println("重复租车结果: " + (rentResult2 ? "成功" : "失败"));
+            
+            // 测试5：还车操作
+            System.out.println("=== 测试5：还车操作 ===");
+            boolean returnResult = car1.returnCar();
+            System.out.println("还车结果: " + (returnResult ? "成功" : "失败"));
+            
+            // 测试6：计算租金
+            System.out.println("=== 测试6：计算租金 ===");
+            double rent = car1.calculateRent(7);
+            System.out.println("7天租金: " + rent + "元");
+            
+            // 测试7：获取车辆总数
+            System.out.println("=== 测试7：获取车辆总数 ===");
+            System.out.println("车辆总数: " + Car.getTotalCars());
+            
+            // 测试8：测试toString方法
+            System.out.println("=== 测试8：测试toString方法 ===");
+            System.out.println(car1.toString());
+            System.out.println(car2.toString());
+            
+            // 测试9：测试参数验证
+            System.out.println("=== 测试9：测试参数验证 ===");
+            try {
+                new Car(null, "奔驰", "C级");
+            } catch (IllegalArgumentException e) {
+                System.out.println("空车牌号测试: " + e.getMessage());
+            }
+            
+            try {
+                car1.calculateRent(0);
+            } catch (IllegalArgumentException e) {
+                System.out.println("天数为0测试: " + e.getMessage());
+            }
+            
+            System.out.println("\n=== 所有测试完成 ===");
+            
+        } catch (Exception e) {
+            System.out.println("测试过程中出现错误: " + e.getMessage());
+            e.printStackTrace();
+        }
+    }
+}