javaweb购物商城系统订单代码

### Java Web 购物商城系统订单管理源码实现

#### 订单实体类定义
为了表示订单信息，创建 `Order` 类作为订单的数据模型。

public class Order {
    private int orderId;
    private String orderNumber;
    private double totalAmount;
    private Date createTime;
    private int userId;

    // Getters and Setters
}

#### 数据访问层 (DAO)

通过 DAO 层与数据库交互，执行增删改查操作。这里展示如何获取所有订单以及根据 ID 获取特定订单的方法。

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

public class OrderDao {

    public List<Order> getAllOrders() throws Exception {
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        try {
            conn = DBUtil.getConnection();
            String sql = "SELECT * FROM orders";
            ps = conn.prepareStatement(sql);
            rs = ps.executeQuery();

            ArrayList<Order> list = new ArrayList<>();
            while(rs.next()){
                Order o = new Order();
                o.setOrderId(rs.getInt("order_id"));
                o.setOrderNumber(rs.getString("order_number"));
                o.setTotalAmount(rs.getDouble("total_amount"));
                o.setCreateTime(rs.getTimestamp("create_time"));
                o.setUserId(rs.getInt("user_id"));

                list.add(o);
            }
            return list;
        } finally {
            close(conn,ps,rs);
        }
    }

    public Order getOrderById(int id) throws Exception{
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        try {
            conn = DBUtil.getConnection();
            String sql = "select * from orders where order_id=?";
            ps = conn.prepareStatement(sql);
            ps.setInt(1,id);

            rs=ps.executeQuery();
            if(rs.next()) {
                Order o = new Order();
                o.setOrderId(id);
                o.setOrderNumber(rs.getString("order_number"));
                o.setTotalAmount(rs.getDouble("total_amount"));
                o.setCreateTime(rs.getDate("create_time"));
                o.setUserId(rs.getInt("user_id"));
                return o;
            }
            return null;
        }finally {
            close(conn,ps,rs);
        }
    }
    
    private void close(Connection c, PreparedStatement p, ResultSet r){
        try {if(r!=null)r.close();} catch(Exception e){e.printStackTrace();}
        try {if(p!=null)p.close();} catch(Exception e){e.printStackTrace();}
        try {if(c!=null)c.close();} catch(Exception e){e.printStackTrace();}
    }
}

#### 业务逻辑层 (Service Layer)
服务层负责处理业务逻辑并调用相应的 DAO 方法完成具体功能。

public class OrderService {
    private final OrderDao dao = new OrderDao();

    /**
     * 查询全部订单
     */
    public List<Order> findAll(){
        try {
            return dao.getAllOrders();
        }catch (Exception ex){
            throw new RuntimeException(ex.getMessage());
        }
    }

    /**
     * 根据ID查询单个订单详情
     */
    public Order findById(Integer id){
        try {
            return dao.getOrderById(id);
        }catch (Exception ex){
            throw new RuntimeException(ex.getMessage());
        }
    }
}

#### 控制器层 (Controller Layer)
控制器接收来自前端页面的请求参数，并返回响应给客户端浏览器。

@WebServlet("/orders")
public class OrderServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException,IOException {
        String action=request.getParameter("action");
        switch(action){
            case "list":
                showAll(request,response);
                break;
            case "detail":
                detail(request,response);
                break;
            default:
                break;
        }
    }

    private void showAll(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{
        OrderService service=new OrderService();
        List<Order> all=service.findAll();
        request.setAttribute("all",all);
        request.getRequestDispatcher("/WEB-INF/jsp/order_list.jsp").forward(request,response);
    }

    private void detail(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{
        Integer id=Integer.parseInt(request.getParameter("id"));
        OrderService service=new OrderService();
        Order one=service.findById(id);
        request.setAttribute("one",one);
        request.getRequestDispatcher("/WEB-INF/jsp/order_detail.jsp").forward(request,response);
    }
}