以下是使用 Spring Boot 构建电商订单系统 API 的详细实践步骤：
1. 项目初始化
首先，你可以使用 Spring Initializr（start.spring.io/ ）来创建一个新的 Spring Boot 项目。在创建项目时，选择以下依赖：
- Spring Web：用于构建 RESTful API。
- Spring Data JPA：用于与数据库交互。
- H2 Database（开发环境使用）：一个轻量级的嵌入式数据库。
2. 数据库设计
订单系统通常涉及几个关键实体：用户、商品、订单和订单项。以下是使用 JPA 注解定义的实体类示例：
用户实体类（User.java）
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
@Entity
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String username;
private String email;
// 构造函数、Getter 和 Setter 方法
public User() {}
public User(String username, String email) {
this.username = username;
this.email = email;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
商品实体类（Product.java）
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import java.math.BigDecimal;
@Entity
public class Product {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
private BigDecimal price;
// 构造函数、Getter 和 Setter 方法
public Product() {}
public Product(String name, BigDecimal price) {
this.name = name;
this.price = price;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public BigDecimal getPrice() {
return price;
}
public void setPrice(BigDecimal price) {
this.price = price;
}
}
订单实体类（Order.java）
import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;
@Entity
public class Order {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@ManyToOne
private User user;
@OneToMany(mappedBy = "order", cascade = CascadeType.ALL)
private List<OrderItem> orderItems = new ArrayList<>();
// 构造函数、Getter 和 Setter 方法
public Order() {}
public Order(User user) {
this.user = user;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public List<OrderItem> getOrderItems() {
return orderItems;
}
public void setOrderItems(List<OrderItem> orderItems) {
this.orderItems = orderItems;
}
}
订单项实体类（OrderItem.java）
import javax.persistence.*;
import java.math.BigDecimal;
@Entity
public class OrderItem {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@ManyToOne
private Product product;
private int quantity;
private BigDecimal totalPrice;
@ManyToOne
private Order order;
// 构造函数、Getter 和 Setter 方法
public OrderItem() {}
public OrderItem(Product product, int quantity, Order order) {
this.product = product;
this.quantity = quantity;
this.totalPrice = product.getPrice().multiply(BigDecimal.valueOf(quantity));
this.order = order;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public Product getProduct() {
return product;
}
public void setProduct(Product product) {
this.product = product;
}
public int getQuantity() {
return quantity;
}
public void setQuantity(int quantity) {
this.quantity = quantity;
}
public BigDecimal getTotalPrice() {
return totalPrice;
}
public void setTotalPrice(BigDecimal totalPrice) {
this.totalPrice = totalPrice;
}
public Order getOrder() {
return order;
}
public void setOrder(Order order) {
this.order = order;
}
}
3. 创建 Repository 接口
为每个实体类创建对应的 Repository 接口，用于与数据库进行交互。
UserRepository.java
import org.springframework.data.jpa.repository.JpaRepository;
public interface ProductRepository extends JpaRepository<Product, Long> {
}
ProductRepository.java
import org.springframework.data.jpa.repository.JpaRepository;
public interface ProductRepository extends JpaRepository<Product, Long> {
}
OrderRepository.java
import org.springframework.data.jpa.repository.JpaRepository;
public interface OrderRepository extends JpaRepository<Order, Long> {
}
4. 创建 Service 层
Service 层负责处理业务逻辑。以下是一个简单的订单服务示例：
OrderService.java
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class OrderService {
@Autowired
private OrderRepository orderRepository;
public Order createOrder(Order order) {
return orderRepository.save(order);
}
public Order getOrderById(Long id) {
return orderRepository.findById(id).orElse(null);
}
public List<Order> getAllOrders() {
return orderRepository.findAll();
}
}
5. 创建 Controller 层
Controller 层负责处理 HTTP 请求，并调用 Service 层的方法。
OrderController.java
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import java.util.List;
@RestController
@RequestMapping("/orders")
public class OrderController {
@Autowired
private OrderService orderService;
@PostMapping
public ResponseEntity<Order> createOrder(@RequestBody Order order) {
Order createdOrder = orderService.createOrder(order);
return new ResponseEntity<>(createdOrder, HttpStatus.CREATED);
}
@GetMapping("/{id}")
public ResponseEntity<Order> getOrderById(@PathVariable Long id) {
Order order = orderService.getOrderById(id);
if (order != null) {
return new ResponseEntity<>(order, HttpStatus.OK);
} else {
return new ResponseEntity<>(HttpStatus.NOT_FOUND);
}
}
@GetMapping
public ResponseEntity<List<Order>> getAllOrders() {
List<Order> orders = orderService.getAllOrders();
return new ResponseEntity<>(orders, HttpStatus.OK);
}
}
6. 配置数据库
在 application.properties 中配置 H2 数据库：
展开
7. 运行项目并测试 API
启动 Spring Boot 应用程序，你可以使用 Postman 或其他 API 测试工具来测试以下 API 端点：
通过以上步骤，你就可以使用 Spring Boot 构建一个简单的电商订单系统 API。在实际项目中，你可能还需要添加更多的功能，如订单状态管理、支付集成、错误处理等。
-
创建订单：
POST http://localhost:8080/orders
请求体示例： -
{ "user": { "id": 1, "username": "john_doe", "email": "john@example.com" }, "orderItems": [ { "product": { "id": 1, "name": "iPhone", "price": 999.99 }, "quantity": 1 } ] } -
获取单个订单：
GET http://localhost:8080/orders/1 -
获取所有订单：
GET http://localhost:8080/orders
