主程序：client.java

package views;

import java.util.Scanner;

public class Client {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        System.out.println("欢迎使用滴滴租车系统：");
        System.out.println("您是否要租车：1是0否");
        Scanner input = new Scanner(System.in);
        int Num;
        if (input.nextInt() == 1) {
            System.out.println("您可租用的车型及价目表：");
            System.out.println("序号         汽车名称           租金                         容量");
            System.out.println("1.    奥迪A4    500元/天             载人：4人");
            System.out.println("2.    马自达               400元/天            载人：4人");
            System.out.println("3.    皮卡雪6    450元/天            载人：4人    载货：2吨");
            System.out.println("4.    金龙                   800元/天            载人：20人");
            System.out.println("5.    松花江               400元/天            载货：40吨");
            System.out.println("6.    依维柯               1000元/天         载货：20吨");
            System.out.println("请输入您要租汽车的数量：");
            Num = input.nextInt();
            AVehicle[] vehicle = new AVehicle[Num];
            for (int i = 0; i < vehicle.length; i++) {
                System.out.println("请输入第" + (i + 1) + "车的序号：");
                switch (input.nextInt()) {
                case 1:
                    vehicle[i] = new Vehicle1();
                    break;
                case 2:
                    vehicle[i] = new Vehicle2();
                    break;
                case 3:
                    vehicle[i] = new Vehicle3();
                    break;
                case 4:
                    vehicle[i] = new Vehicle4();
                    break;
                case 5:
                    vehicle[i] = new Vehicle5();
                    break;
                case 6:
                    vehicle[i] = new Vehicle6();
                    break;
                default:
                    System.out.println("无此序号车辆");
                    input.close();
                }
            }
            System.out.println("请输入租车天数：");
            int Days = input.nextInt();
            int manAvailableCount = 0;
            int goodsAvailableCount = 0;
            String manAvailableVehicle = "";
            String goodsAvailableVehicle = "";
            int capacityAll = 0;
            float burdenAll = 0f;
            float price = 0;
            System.out.println("您的账单：");
            for (int i = 0; i < vehicle.length; i++) {
                if (vehicle[i].capacity != 0) {
                    manAvailableCount++;
                    manAvailableVehicle = manAvailableVehicle + vehicle[i].name + "    ";
                    capacityAll = capacityAll + vehicle[i].capacity;
                }
                if (vehicle[i].burden != 0) {
                    goodsAvailableCount++;
                    goodsAvailableVehicle = goodsAvailableVehicle + vehicle[i].name + "    ";
                    burdenAll = burdenAll + vehicle[i].burden;
                }
                price = price + vehicle[i].rent * Days;
            }
            System.out.println("*****可载人车有" + manAvailableCount + "辆：");
            System.out.println(manAvailableVehicle.toString() + "共可载" + capacityAll + "人");
            System.out.println("*****可载货车有" + goodsAvailableCount + "辆：");
            System.out.println(goodsAvailableVehicle.toString() + "共可载" + burdenAll + "吨");
            System.out.println("*****租车总价格：" + price + "元");
            input.close();
        } else {
            input.close();
            System.out.println("谢谢使用");
        }
    }

}

一个父类AVehicle.java

package views;

public class AVehicle {
    public int NO;
    public String name;
    public float rent; // 租金
    public int capacity; // 载人数
    public float burden; // 载货量
    public AVehicle(){
        this.NO = 0;
        this.name = "";
        this.rent = 0f;
        this.capacity = 0;
        this.burden = 0f;
    }
}

6个子类Vehicle1.java ...... Vehicle6.java类似。
Vehicle1.java

package views;

public class Vehicle1 extends AVehicle {
    public Vehicle1() {
        this.name = "奥迪A4";
        this.NO = 1;
        this.rent = 500f;
        this.capacity = 4;
    }
}

Vehicle2.java

package views;

public class Vehicle2 extends AVehicle {
    public Vehicle2() {
        this.NO = 2;
        this.name = "马自达6";
        this.rent = 400f; // 租金
        this.capacity = 4; // 载人数

    }
}

Vehicle3.java

package views;

public class Vehicle3 extends AVehicle {
    public Vehicle3() {
        this.NO = 3;
        this.name = "皮卡雪6";
        this.rent = 450f; // 租金
        this.capacity = 4; // 载人数
        this.burden = 2; // 载货量
    }
}

Vehicle4.java

package views;

public class Vehicle4 extends AVehicle {
    public Vehicle4() {
        this.NO = 4;
        this.name = "金龙";
        this.rent = 800f; // 租金
        this.capacity = 20; // 载人数

    }
}

Vehicle5.java

package views;

public class Vehicle5 extends AVehicle {
    public Vehicle5() {
        this.NO = 5;
        this.name = "松花江";
        this.rent = 400f; // 租金
        this.burden = 4f; // 载货量
    }
}

Vehicle6.java

package views;

public class Vehicle6 extends AVehicle {
    public Vehicle6() {
        this.NO = 6;
        this.name = "依维柯";
        this.rent = 1000f; // 租金
        this.burden = 20f; // 载货量
    }
}

实际运行图：