感觉写了好多代码，很多地方都可以优化，但是我刚学，不知道怎么修改， 希望各位可以提供点思路，感谢！以下是代码：

//父类：
package Dada;

public abstract class Vehicle {

    public int price;
    public int people;
    public String name;
    public double load;
    abstract void info();

}

子类：奥迪

package Dada;

public class Audi extends Vehicle {
    public final int price = 500;
    public final int people = 4;
    public final int id =1;
    public final String name = "奥迪A4";
    @Override
    void info() {
        System.out.println(id+"."+" "+name+" "+price+"/天"+" "+"载人:"+people+"人");
    }
}

子类：马自达

package Dada;

public class Mazda extends Vehicle {
    public final int price = 400;
    public final int people = 4;
    public final int id =2;
    public final String name = "马自达6";
    @Override
    void info() {
        System.out.println(id+"."+" "+name+" "+price+"/天"+" "+"载人:"+people+"人");
    }
}

子类：皮卡雪6

package Dada;

public class Pika extends Vehicle {
    public final int price = 450;
    public final int people = 4;
    public final int id =3;
    public final String name = "皮卡雪6";
    public final double load = 2;
    @Override
    void info() {
        System.out.println(id+"."+" "+name+" "+price+"/天"+" "+"载人:"+people+"人"+"载货"+load+"吨");
    }
}

子类：金龙

package Dada;

public class Jinlong extends Vehicle {
    public final int price = 800;
    public final int people = 20;
    public final int id =4;
    public final String name = "金龙";
    @Override
    void info() {
        System.out.println(id+"."+" "+name+" "+price+"/天"+" "+"载人:"+people+"人");
    }
}

子类：松花江

package Dada;

public class Songhuajiang extends Vehicle {
    public final int price = 400;
    public final double load = 4;
    public final int id =5;
    public final String name = "松花江";
    @Override
    void info() {
        System.out.println(id+"."+" "+name+" "+price+"/天"+" "+"载货:"+load+"吨");
    }
}

子类：依维柯

package Dada;

public class Yiweike extends Vehicle {
    public final int price = 1000;
    public final double load = 20;
    public final int id =6;
    public final String name = "依维柯";
    @Override
    void info() {
        System.out.println(id+"."+" "+name+" "+price+"/天"+" "+"载货:"+load+"吨");
    }
}

测试类：

package Dada;

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class test {


    public static void main(String[] args){

        List<Integer> data;
        List<String> passengerVehicleName=new ArrayList<>();
        List<String> goodsVehicleName=new ArrayList<>();
        System.out.println("欢迎使用答答租车系统：");
        System.out.println("您是否要租车？ 1 是， 0 否");
        Scanner select = new Scanner(System.in);
        int answer = select.nextInt();
        int dayNum;
        int money =0;
        int people=0;
        double goods =0;

        switch (answer){
            case 1:
                info();
                break;
            case 0:
                System.out.println("不租车你点进来干嘛，别闹！");
                break;
            default:
                System.out.println("你好调皮，再见。");

        }

        data = rentNumber();
        dayNum = data.get(data.size()-1);
        data.remove(data.size()-1);

        for (int i: data){
            switch (i){
                case 1:
                    Audi  audi = new Audi();
                    money= money+audi.price*dayNum;
                    people= people+audi.people;
                    passengerVehicleName.add(audi.name);
                    break;
                case 2:
                    Mazda mazda = new Mazda();
                    money = money+mazda.price*dayNum;
                    people = people+mazda.people;
                    passengerVehicleName.add(mazda.name);
                    break;
                case 3:
                    Pika piKa = new Pika();
                    money=money+piKa.price*dayNum;
                    people=people+piKa.people;
                    goods=goods+piKa.load;
                    passengerVehicleName.add(piKa.name);
                    goodsVehicleName.add(piKa.name);
                    break;
                case 4:
                    Jinlong jinLong = new Jinlong();
                    money = money + jinLong.price*dayNum;
                    people = people+jinLong.people;
                    passengerVehicleName.add(jinLong.name);
                    break;
                case 5:
                    Songhuajiang songHuaJiang = new Songhuajiang();
                    money = money+songHuaJiang.price*dayNum;
                    goods = goods+songHuaJiang.load;
                    goodsVehicleName.add(songHuaJiang.name);
                    break;
                case 6:
                    Yiweike yiWeiKe = new Yiweike();
                    money = money + yiWeiKe.price*dayNum;
                    goods = goods + yiWeiKe.load;
                    goodsVehicleName.add(yiWeiKe.name);
                    break;
            }
        }

        System.out.println("您的账单：");
        if (people!=0){
            System.out.println("***可载人的车有:");
            for (String i:passengerVehicleName
            ) {
                System.out.print(i+" ");
            }
            System.out.println("共载人："+people+"人");
            System.out.println();
        }

        if (goods!=0){
            System.out.println("***可载货的车有:");
            for (String i:goodsVehicleName
            ) {
                System.out.print(i+" ");
            }
            System.out.println("共载货："+goods+"吨");
            System.out.println();
        }

        System.out.println("***租车总价格为"+money+"元");
    }

    static void info(){
        System.out.println("您可租车的类型及价目表如下：");
        System.out.println("序号 汽车名称 租金   容量");
        Vehicle Audi = new Audi();
        Audi.info();
        Vehicle Mazda = new Mazda();
        Mazda.info();
        Vehicle Pika = new Pika();
        Pika.info();
        Vehicle Jinlong = new Jinlong();
        Jinlong.info();
        Vehicle Songhuajiang = new Songhuajiang();
        Songhuajiang.info();
        Vehicle Yiweike = new Yiweike();
        Yiweike.info();
    }

    public static List rentNumber(){
        List<Integer> selection = new ArrayList<>();
        System.out.println("请输入您要租车的数量：");
        Scanner rn = new Scanner(System.in);
        int number = rn.nextInt();

        for (int i = 1; i<= number; i++){
            System.out.println("请输入第"+i+"辆车的序号：");
            Scanner num = new Scanner(System.in);
            int a = num.nextInt();
            selection.add(a);
        }
        System.out.println("请输入租车天数：");
        Scanner data = new Scanner(System.in);
        int dayNum = data.nextInt();
        selection.add(dayNum);
        return selection;
    }
}