根据自己的理解写的，还不完善，错误的地方还请不吝赐教，谢谢！
cars父类：

public abstract class Car {

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public double getGoods() {
        return goods;
    }

    public void setGoods(double goods) {
        this.goods = goods;
    }

    public int getPeople() {
        return people;
    }

    public void setPeople(int people) {
        this.people = people;
    }

    public double price;
    public String title;
    public int people;
    public double goods;

    @Override
    public String toString() {
        return  title + " t " + price + "/天t 载人:" + people + "/人";
    }
}

货车，客车，皮卡车子类：

public class Trunck extends Car {
    /**
     * Override construct function.
     */
    public Trunck(String title, double price, int goods){
        this.price = price;
        this.title = title;
        this.goods = goods;
    }
    /**
     * Override toString function.
     */
    @Override
    public String toString() {
        return  title + "t " + price + "/天t 载货:" + goods + "吨";
    }
}

public class Bus extends Car{
    /**
     * Override construct function.
     */
    public Bus(String title, double price, int people){
        this.price = price;
        this.title = title;
        this.people = people;
    }
}

public class Pickup extends Car{
    /**
     * Override construct function.
     */
    public Pickup(String title, double price, int people, double goods){

        this.price = price;
        this.title = title;
        this.people = people;
        this.goods = goods;
    }
    /**
     * Override toString function.
     */
    @Override
    public String toString() {
        return  title + "t " + price + "/天t 载人:" + people + "/人t 载货:" + goods + "吨";
    }
}

用户选项类：

public class SelectInformation {

    public double getDays() {
        return days;
    }

    public void setDays(double days) {
        this.days = days;
    }

    public double getSumPrice() {
        return sumPrice;
    }

    public void setSumPrice(double sumPrice) {
        this.sumPrice += sumPrice;
    }

    public int getSumPeople() {
        return sumPeople;
    }

    public void setSumPeople(int sumPeople) {
        this.sumPeople += sumPeople;
    }

    public double getSumTrunk() {
        return sumTrunk;
    }

    public void setSumTrunk(double sumTrunk) {
        this.sumTrunk += sumTrunk;
    }

    public double getTotalPrice() {
        return totalPrice;
    }

    public void setTotalPrice(double days, double price) {
        this.totalPrice = days * price;
    }

    public int getCarRental() {
        return carRental;
    }

    public void setCarRental(int carRental) {
        this.carRental = carRental;
    }

    public ArrayList getPcarsList() {
        return pcarsList;
    }

    public void setPcarsList(ArrayList pcarsList) {
        this.pcarsList = pcarsList;
    }

    public ArrayList getTcarsList() {
        return tcarsList;
    }

    public void setTcarsList(ArrayList tcarsList) {
        this.tcarsList = tcarsList;
    }

    public double days;
    public int carRental;
    public double sumPrice;
    public int sumPeople;
    public double sumTrunk;
    public double totalPrice;
    public ArrayList pcarsList;
    public ArrayList tcarsList;
}

main测试类：

public class Main {
    /**
     * Print car rental information.
     */
    public static void printInfo(Car[] cars) {
        System.out.println("您可租车的类型及其价目表:");
        System.out.println("序号  汽车名称  租金     容量");
        for (int i = 0; i  cars.length) {
            System.out.println("对不起,您输入的数量有误,请重新输入:");
            System.out.println("请输入您要租用的汽车数量:");
            num = input.nextInt();
        }
        selInfo.setCarRental(num);
        if (0  tmpPlist = new ArrayList();
            ArrayList tmpTlist = new ArrayList();
            for (int i = 0; i