整体思路

1. 创建名为Car的抽象类，声明共有属性（名字，载客量busLoad，载货量trunkLoad，租金）;
2. 分别创建卡车类Trunk，小轿车类Bus，皮卡类PickUp，均继承于Car类;
3. 在主方法中分别创建各种车的对象，并用一个数组存放这些对象，最后对用户输入的序号对应的租车价格计算；

/**
 * 抽象类
 * Created by haivo on 2016/3/24.
 */
public abstract class Car {
    public String name = "";
    public  int trunkLoad = 0;
    public int busLoad = 0;
    public  int price = 0;
}

/**
 * 卡车（东风，解放）
 * Created by haivo on 2016/3/24.
 */
public class Trunk extends Car{
    public Trunk(String name,int trunkLoad,int price){
        this.name = name;
        this.trunkLoad = trunkLoad;
        this.price = price;
    }

    @Override
    public String toString() {
        return String.format("%s\t\t%s\t\t%d%s\t\t%d%s", name,"-",trunkLoad,"吨",price,"元/天");
    }
}

/**
 * 小轿车（奔驰，雪佛兰）
 * Created by haivo on 2016/3/24.
 */
public class Bus extends Car {
    public Bus(String name,int busLoad,int price){
        this.name = name;
        this.busLoad = busLoad;
        this.price = price;
    }

    @Override
    public String toString() {
        return String.format("%3s\t%d%s\t\t%s\t\t%d%s", name,busLoad,"人","-",price,"元/天");
    }
}

/**
 * 皮卡（风骏，拓路者）
 * Created by haivo on 2016/3/24.
 */
public class PickUp extends Car {
    public PickUp(String name,int busLoad,int trunkLoad,int price){
        this.name = name;
        this.busLoad = busLoad;
        this.trunkLoad = trunkLoad;
        this.price = price;
    }
    @Override
    public String toString() {
        return String.format("%3s\t%d%s\t\t%d%s\t\t%d%s", name,busLoad,"人",trunkLoad,"吨",price,"元/天");
    }
}

/**
 * 程序入口
 * Created by haivo on 2016/3/24.
 */
public class SystemSurface {
    public static void main(String[] args) {

        Trunk donfFeng = new Trunk("东风", 10, 400);
        Trunk jieFang = new Trunk("解放", 15, 500);
        Bus xueFuLan = new Bus("雪佛兰", 6, 200);
        Bus benz = new Bus("奔驰", 4, 300);
        PickUp fengJun = new PickUp("风骏", 4, 3, 200);
        PickUp tuoLuZhe = new PickUp("拓路者", 4, 5, 260);
        Car car[] = new Car[]{donfFeng,jieFang,xueFuLan,benz,fengJun,tuoLuZhe};
        String[] carInfo = new String[]{
                donfFeng.toString(),
                jieFang.toString(),
                xueFuLan.toString(),
                benz.toString(),
                fengJun.toString(),
                tuoLuZhe.toString()
        };

        System.out.println("欢迎使用达达租车系统.");
        System.out.println("以下是价目表：\n");
        System.out.println("序号\t\t汽车名称\t载客量\t载货量\t租金\t");
        for(int num =0;num<=carInfo.length-1;num++) {
            System.out.println(" "+(num+1)+"\t\t"+carInfo[num]);
        }
        System.out.println("您要租几辆车？");
        Scanner scanner = new Scanner(System.in);
        int carNumber = scanner.nextInt();//租车数量carNum
        int chooseNo[] = new int[20]; //要租的车的序号chooseNo数组保存
        for(int i=1;i<=carNumber;i++){
            System.out.print("请输入第"+i+"辆车的序号：");
            chooseNo[i] = scanner.nextInt();
        }
        int subPrice = 0;
        for(int i=1;i<=carNumber;i++){
            subPrice = subPrice + car[(chooseNo[i])-1].price;
        }
        System.out.println("您需要支付的金额是："+subPrice);
    }
}