Java超详细教你写一个网络购书系统案例

public class Book {
    private int id;
    private String name;
    private double price;
    private int stock;
    //无参构造
    public Book() {
    }
    //带四个参数的构造
    public Book(int id, String name, double price, int stock) {
        this.id = id;
        this.name = name;
        this.price = price;
        this.stock = stock;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public double getPrice() {
        return price;
    }

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

    public int getStock() {
        return stock;
    }

    public void setStock(int stock) {
        this.stock = stock;
    }
}

public class OrderItem {
    private Book book;
    private int num;

    public OrderItem() {
    }
    public OrderItem(Book book, int num) {
        this.book = book;
        this.num = num;
    }

    public Book getBook() {
        return book;
    }

    public void setBook(Book book) {
        this.book = book;
    }

    public int getNum() {
        return num;
    }

    public void setNum(int num) {
        this.num = num;
    }
}

public class Order {
    private String orderID;
    private OrderItem[] items = new OrderItem[3];
    private double totalMoney;

    public Order() {
    }

    public Order(String orderID) {
        this.orderID = orderID;
    }

    public String getOrderID() {
        return orderID;
    }

    public void setOrderID(String orderID) {
        this.orderID = orderID;
    }

    public OrderItem[] getItems() {
        return items;
    }

    public void setItems(int i,OrderItem item) {
        items[i]=item;
    }

    public double getTotalMoney() {
        for (int i = 0; i < items.length; i++) {
            totalMoney += items[i].getNum()*items[i].getBook().getPrice();
        }
        return totalMoney;
    }
}

    private static void printBooks(Book[] books) {
        books[0]=new Book(1,"Java2实用教程",10,20);
        books[1]=new Book(2,"计算机网络原理",20,20);
        books[2]=new Book(3,"概率论数理统计",30,20);

        System.out.println("图书编号\t图书名称\t\t\t图书单价\t图书库存");
        for (int i = 0; i < books.length; i++) {
            Book b=books[i];
            System.out.println("\t"+b.getId() +"\t\t"+b.getName()+"\t\t"+b.getPrice()+"\t\t"+b.getStock());
        }
    }

    private static Order buy(Book[] books) {
        Order order = new Order("001");
        Scanner sc=new Scanner(System.in);
        for (int i = 0; i < books.length; i++) {
            System.out.println("请输入图书的编号：");
            int id = sc.nextInt();
            System.out.println("请输入购买的数量：");
            int num = sc.nextInt();
            OrderItem item = new OrderItem(books[id-1],num);
            order.setItems(i,item);
        }
        return order;
    }

    private static void printInfo(Order order) {
        System.out.println("订单编号："+order.getOrderID());
        System.out.println("图书名称\t\t图书单价\t购买的数量");
        OrderItem[] items = order.getItems();
        for (int i = 0; i < items.length; i++) {
            System.out.println(items[i].getBook().getName()+"\t"+items[i].getBook().getPrice()+"\t\t"+items[i].getNum());
        }
        System.out.println("----------------------------------");
        System.out.println("总金额："+order.getTotalMoney());
    }

    public static void main(String[] args) {
        Book[] books = new Book[3];

        //调用打印图书信息的方法
        printBooks(books);

        //调用购买图书的方法
        Order order = buy(books);

        //调用打印订单信息方法
        printInfo(order);
    }