• 父类

package gakki;

public abstract class Car {
    public String name;
    public int price;
    public int people;
    public int weight;
}

• 子类1（只载人）

package gakki;

public class Bus extends Car {
    public Bus(String name,int price,int people){
        this.name=name;
        this.price=price;
        this.people=people;
    }

    @Override
    public String toString() {
        return (name+"t"+price+"t"+people+"人");
    } 
}

• 子类2（只载货）

package gakki;

public class KaCar extends Car {
    public KaCar(String name,int price,int weight){
        this.name=name;
        this.price=price;
        this.weight=weight;
    }

    @Override
    public String toString() {
        return (name+"t"+price+"t"+weight+"吨");
    }
}

• 子类3（既载人又载货）

package gakki;

public class PiCar extends Car {
    public PiCar(String name,int  price,int people,int weight){
        this.name=name;
        this.price=price;
        this.people=people;
        this.weight=weight;
    }

    @Override
    public String toString() {
        return (name+"t"+price+"t"+people+"人,"+weight+"吨");
    }
}

• 主代码

package gakki;

import java.util.Scanner;

public class Initial5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int totalPeople=0,totalPrice=0,totalWeight=0;
        String ZaiKe="",ZaiHuo="";
        Car[] cars={new Bus("玛莎拉蒂", 500,4),
                new Bus("大黄蜂",700,4),
                new KaCar("擎天柱", 1000, 20),
                new KaCar("威震天",900,30),
                new PiCar("福特", 800, 2, 3),
                new PiCar("雷诺",600,2,10)
        };
        System.out.println("欢迎使用gakki租车系统");
        System.out.println("您是否要租车：1是 0否");
        Scanner scanner=new Scanner(System.in);
        int a = scanner.nextInt();
        if(a==1){
            System.out.println("你可租车的类型及其价目表");
            System.out.println("序号t汽车名称t租金t容量t");
            for(int i=0;i

• 运行结果
  
  我也是初学者，如果有不理解的地方，可以一起交流。