java/w3/Car.java

package com.rental;
public class Car{
	//私有属性
	private String licensePlate;
	private String brand;
	private String model;
	private double dailyRent;
	private boolean isRented;
	//静态变量
	private static int totalCars = 0;
	//构造方法
	public Car(String licensePlate,String brand,String model,double dailyRent){
		this.licensePlate =	licensePlate;
		this.brand = brand;
		this.model = brand;
		setDailyRent(dailyRent);
		this.isRented = false;
		totalCars++;
	}
	public Car(String licensePlate,String brand,String model){
		this(licensePlate,brand,model,300.0);
	}
	//Getter/Setter规则
	public String getLicensePlate(){
		return licensePlate;
	}
	public String getBrand(){
		return brand;
	}
	public String getModel(){
		return model;
	}
	public double getDailyRent(){
		return this.dailyRent;
	}
	public boolean isRented(){
		return isRented;
	}
	public void setBrand(String brand){
		this.brand=brand;
	}
	public void setModel(String model){
		this.model=model;
	}
	public void setDailyRent(double dailyRent){
		if (dailyRent>0){
			this.dailyRent=dailyRent;
		}else{
			System.out.println("日租金必须大于0，设置失败，保持原值。");
		}
	}
	//业务方法
	public void rentCar() {
        if (this.isRented) {
            System.out.println("车辆已租出，无法再次租用。");
        } else {
            this.isRented = true;
            System.out.println("车辆" + this.licensePlate + "租用成功。");
        }
    }
    public void returnCar() {
        if (!this.isRented) {
            System.out.println("车辆未被租用，无需归还。");
        } else {
            this.isRented = false;
            System.out.println("车辆" + this.licensePlate + "归还成功。");
        }
    }
    public double calculateRent(int days) {
        return this.dailyRent * days;
    }
    //静态方法
    public static int getTotalCars() {
        return totalCars;
    }
    //displayInfo方法
    public void displayInfo() {
        String status = this.isRented ? "已租出" : "可租";
        System.out.println("车牌: " + this.licensePlate + ", 品牌: " + this.brand + 
                           ", 型号: " + this.model + ", 日租金: " + this.dailyRent + 
                           "元/天, 状态: " + status);
    }
}