通过java实现根据封装的知识，编写程序，题目要求： 某汽车销售公司，销售各种小车，有品牌，型号，座位数，颜色，单价，上个月销售量等属性，及计算月销售金额方法。 要求：（1）创建 Car 类封装上述属性与方法。 （2）创建测试类，实例化多部小车，键盘输入数据如图数据，输出相应内容

回答：非常感谢您的问题，以下是针对您提供的题目所编写的Java代码：

public class Car {
    private String brand;
    private String model;
    private int seats;
    private String color;
    private double price;
    private int lastMonthSales;

    public Car(String brand, String model, int seats, String color, double price, int lastMonthSales) {
        this.brand = brand;
        this.model = model;
        this.seats = seats;
        this.color = color;
        this.price = price;
        this.lastMonthSales = lastMonthSales;
    }

    public double calculateMonthlySales() {
        return price * lastMonthSales;
    }

    public String toString() {
        return "Brand: " + brand + "\nModel: " + model + "\nSeats: " + seats
            + "\nColor: " + color + "\nPrice: " + price + "\nLast month sales: " + lastMonthSales;
    }
}

import java.util.Scanner;

public class CarTest {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.print("Enter the number of cars to add: ");
        int numCars = scanner.nextInt();
        scanner.nextLine();

        Car[] cars = new Car[numCars];

        for (int i = 0; i < numCars; i++) {
            System.out.println("*** Enter car #" + (i + 1) + " details ***");
            System.out.print("Brand: ");
            String brand = scanner.nextLine();
            System.out.print("Model: ");
            String model = scanner.nextLine();
            System.out.print("Seats: ");
            int seats = scanner.nextInt();
            scanner.nextLine(); // consume newline left-over
            System.out.print("Color: ");
            String color = scanner.nextLine();
            System.out.print("Price: ");
            double price = scanner.nextDouble();
            scanner.nextLine(); // consume newline left-over
            System.out.print("Last month sales: ");
            int lastMonthSales = scanner.nextInt();
            scanner.nextLine(); // consume newline left-over

            cars[i] = new Car(brand, model, seats, color, price, lastMonthSales);
            System.out.println("*** Car added! ***");
        }

        for (int i = 0; i < numCars; i++) {
            System.out.println("\n*** Car #" + (i + 1) + " details ***");
            System.out.println(cars[i].toString());
            System.out.println("Monthly sales: " + cars[i].calculateMonthlySales());
        }
    }
}

您可以在控制台输入不同的汽车信息，程序会按要求求出每辆汽车的月销售额并输出。请注意代码中的注释以获得更好的理解。