面向初学者的 Java 购物系统代码124

对于有志于学习 Java 编程的开发人员来说，创建一个功能齐全的购物系统是一个绝佳的项目。它涵盖了广泛的编程概念，包括对象导向编程、数据库交互和用户界面设计。本文将指导您逐步创建自己的 Java 购物系统，该系统将具备浏览商品、添加商品到购物车以及结账等基本功能。

数据库结构

在开始编码之前，我们需要设计一个数据库来存储商品、客户和订单数据。以下是一个示例数据库结构：```
CREATE TABLE Products (
id INT NOT NULL AUTO_INCREMENT,
name VARCHAR(255) NOT NULL,
price DECIMAL(10, 2) NOT NULL,
PRIMARY KEY (id)
);
CREATE TABLE Customers (
id INT NOT NULL AUTO_INCREMENT,
name VARCHAR(255) NOT NULL,
email VARCHAR(255) NOT NULL,
PRIMARY KEY (id)
);
CREATE TABLE Orders (
id INT NOT NULL AUTO_INCREMENT,
customer_id INT NOT NULL,
total_price DECIMAL(10, 2) NOT NULL,
created_at TIMESTAMP NOT NULL,
PRIMARY KEY (id),
FOREIGN KEY (customer_id) REFERENCES Customers (id)
);
CREATE TABLE Order_Items (
order_id INT NOT NULL,
product_id INT NOT NULL,
quantity INT NOT NULL,
PRIMARY KEY (order_id, product_id),
FOREIGN KEY (order_id) REFERENCES Orders (id),
FOREIGN KEY (product_id) REFERENCES Products (id)
);
```

Java 代码

有了数据库结构后，我们可以编写 Java 代码来与之交互。以下是购物系统的主要代码段：```java
// 实体类
public class Product {
private int id;
private String name;
private double price;
// 省略 getter 和 setter 方法
}
public class Customer {
private int id;
private String name;
private String email;
// 省略 getter 和 setter 方法
}
public class Order {
private int id;
private Customer customer;
private double totalPrice;
private Date createdAt;
// 省略 getter 和 setter 方法
}
public class OrderItem {
private Order order;
private Product product;
private int quantity;
// 省略 getter 和 setter 方法
}
// DAO 类
public interface ProductDao {
List getAllProducts();
Product getProductById(int id);
void addProduct(Product product);
void updateProduct(Product product);
void deleteProduct(int id);
}
public interface CustomerDao {
List getAllCustomers();
Customer getCustomerById(int id);
void addCustomer(Customer customer);
void updateCustomer(Customer customer);
void deleteCustomer(int id);
}
public interface OrderDao {
List getAllOrders();
Order getOrderById(int id);
void addOrder(Order order);
void updateOrder(Order order);
void deleteOrder(int id);
}
// 服务类
public class ProductService {
private ProductDao productDao;
public ProductService(ProductDao productDao) {
= productDao;
}
public List getAllProducts() {
return ();
}
// 省略其他方法
}
public class CustomerService {
private CustomerDao customerDao;
public CustomerService(CustomerDao customerDao) {
= customerDao;
}
public List getAllCustomers() {
return ();
}
// 省略其他方法
}
public class OrderService {
private OrderDao orderDao;
public OrderService(OrderDao orderDao) {
= orderDao;
}
public List getAllOrders() {
return ();
}
// 省略其他方法
}
// 控制器类
public class ShoppingController {
private ProductService productService;
private CustomerService customerService;
private OrderService orderService;
public ShoppingController(ProductService productService, CustomerService customerService, OrderService orderService) {
= productService;
= customerService;
= orderService;
}
@GetMapping("/products")
public List getAllProducts() {
return ();
}
// 省略其他方法
}
```