创建了两个接口IPeopleCapacity（具有载客容量）、ICargoCapacity（具有载货容量）；一个父类Vehicle代表车辆具有序号、名字、租用价钱属性，三个子类Car汽车（只载人）、Truck货车（只载货）、Pickup皮卡（能载人也能载货）。程序做了部分注释。希望可以多多交流。请多指教！

IPeopleCapacity.java

package com.imooc;
//创建接口IPeopleCapacity，具有载人容量
public interface IPeopleCapacity {
    public int getPeopleCapacity();
}

ICargoCapacity.java

package com.imooc;
//创建接口ICargoCapacity，具有载货容量
public interface ICargoCapacity {
    public int getCargoCapacity();
}

Vehicle.java

package com.imooc;
//创建父类Vehicle，子类将拥有父类所有的方法和属性
public class Vehicle {
    public int id;
    public String name;
    public int rentPrice;
}

Car.java

package com.imooc;
//创建子类Car汽车，继承父类Vehicle，且遵守接口IPeopleCapacity具有载人容量
public class Car extends Vehicle implements IPeopleCapacity{
    public int peopleNum;
    public Car(int id,String name,int rentPrice,int peopleNum) {
        this.id=id;
        this.name=name;
        this.rentPrice=rentPrice;
        this.peopleNum=peopleNum;
    }
    public String toString() {
        return id+"t"+name+"t"+rentPrice+"元/天t"+peopleNum+"人";
    }
    @Override
    public int getPeopleCapacity() {
        // TODO Auto-generated method stub
        return peopleNum;
    }
}

Truck.java

package com.imooc;
//创建子类Truck货车，继承父类Vehicle，且遵守接口ICargoCapacity具有载货容量
public class Truck extends Vehicle implements ICargoCapacity{
    public int cargoWeight;
    public Truck(int id,String name,int rentPrice,int cargoWeight) {
        this.id=id;
        this.name=name;
        this.rentPrice=rentPrice;
        this.cargoWeight=cargoWeight;
    }
    public String toString() {
        return id+"t"+name+"t"+rentPrice+"元/天t"+cargoWeight+"吨";
    }
    @Override
    public int getCargoCapacity() {
        // TODO Auto-generated method stub
        return cargoWeight;
    }
}

Pickup.java

package com.imooc;
//创建子类Pickup皮卡，继承父类Vehicle，且遵守接口IPeopleCapacity和ICargoCapacity具，有载人容量和载货容量
public class Pickup extends Vehicle implements ICargoCapacity,IPeopleCapacity{
    public int peopleNum;
    public int cargoWeight;
    public Pickup(int id,String name,int rentPrice,int peopleNum,int cargoWeight) {
        this.id=id;
        this.name=name;
        this.rentPrice=rentPrice;
        this.peopleNum=peopleNum;
        this.cargoWeight=cargoWeight;
    }
    public String toString() {
        return id+"t"+name+"t"+rentPrice+"元/天t"+peopleNum+"人,"+cargoWeight+"吨";
    }
    @Override
    public int getPeopleCapacity() {
        // TODO Auto-generated method stub
        return peopleNum;
    }
    @Override
    public int getCargoCapacity() {
        // TODO Auto-generated method stub
        return cargoWeight;
    }
}

Test.java

package com.imooc;
import java.util.Scanner;
public class Test {
    int rentSum=0;//总租金
    int peopleSum=0;//总载客数
    int cargoSum=0;//总载货数
    String peopleVehicle="",cargoVehicle="";//所租用的载人车型和载客车型
    public void method() {
        // TODO Auto-generated method stub
        //通过父类Vehicle的引用指向子类Car、Pickup、Truck的对象，存放在Vehicles[]数组中
        Vehicle[] Vehicles= {new Car(1,"奥迪A4",500,4),
                            new Car(2,"马自达6",400,4),
                            new Pickup(3,"皮卡雪6",450,4,2),
                            new Car(4,"金龙",800,20),
                            new Truck(5,"松花江",400,4),
                            new Truck(6,"依维柯",1000,20)};

        System.out.println("欢迎使用嗒嗒租车系统：");
        System.out.println("您是否要租车：1.是;2.否");
        Scanner input1=new Scanner(System.in);
        switch(input1.nextInt()){
        case 1:{
            System.out.println("您可租用的类型及其价目表："+"n"+"序号t"+"车型t"+"租金t"+"容量");
            for(int i=0;i0) {
                for(int j=1;j0) {
                rentSum=rentSum*day; 
                System.out.println("****您的账单：n****您租用的可载人的车："+peopleVehicle+"n****共可载客："+peopleSum+"人");
                System.out.println("****您租用的可载货的车："+cargoVehicle+"n****共可载货："+cargoSum+"吨");
                System.out.println("****租车总价格："+rentSum+"元");
                System.out.println("n******感谢使用嗒嗒租车系统,祝您生活愉快！******");
                System.exit(0);
                } else{
                System.out.println("输入的租车天数有误，系统无法验证！");
                System.exit(0);}
            }else {
                System.out.println("输入的租车数量有误，系统无法验证！");
                System.exit(0);
            }
            break;
        }
        case 2: {
            System.out.println("******感谢使用嗒嗒租车系统,祝您生活愉快！******");
            System.exit(0);
            break;}
        default:{
            System.out.println("您输入的数字有误，系统无法验证！");
            System.out.println("n******感谢使用嗒嗒租车系统,祝您生活愉快！******");
            System.exit(0);}
            }
        }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Test service=new Test();
        service.method();
    }
}