Java基础100 把购物车中的商品购买支付、生成订单（Servlet技术，简单演示，支付功能省略，只是演示整个流程而已）

1、效果图示  

2、相关代码  

注：这里只是简单演示，很多代码并不是那么完善，且 没有写支付功能，只是简单演示整个流程而已

  2.1、数据库相关表

CREATE TABLE orders( -- 订单表
  id VARCHAR(100) PRIMARY KEY,
  orderId VARCHAR(100) NOT NULL UNIQUE,
  num INT,
  price FLOAT(8,2),
state INT,
  user_id VARCHAR(100),
  CONSTRAINT user_id_fk FOREIGN KEY(user_id) REFERENCES Users(id)
);

CREATE TABLE ordersitem( -- 订单项表
  id VARCHAR(100) PRIMARY KEY,
  num INT,
  price FLOAT(8,2),
  orders_id VARCHAR(100),
  book_id VARCHAR(100),
  CONSTRAINT orders_id_fk FOREIGN KEY(orders_id) REFERENCES orders(id),
  CONSTRAINT book_id_fk FOREIGN KEY(book_id) REFERENCES book(id)
);

2.2、实体类

package com.shore.entity;

import java.util.ArrayList;
import java.util.List;

/**
 * @author DSHORE/2019-4-26
 *
 */
//订单信息：对应的就是购物车的基本信息
public class Orders{  
    private String id;//订单:用户+订单项     数据库中:只有用户的id   只有订单项的id 
    private String orderId;//订单号。not null  unique
    private int num;//数量
    private float price;//付款金额
    private int state;//0表示未发货  1表示已发货
    private List<OrdersItem> items = new ArrayList<OrdersItem>();//订单中的订单项 //id
    private User user;//id //该订单是属于哪个用户

    public String getId() {
        return id;
    }

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

    public String getOrderId() {
        return orderId;
    }

    public void setOrderId(String orderId) {
        this.orderId = orderId;
    }

    public int getNum() {
        return num;
    }

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

    public float getPrice() {
        return price;
    }

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

    public int getState() {
        return state;
    }

    public void setState(int state) {
        this.state = state;
    }

    public List<OrdersItem> getItems() {
        return items;
    }

    public void setItems(List<OrdersItem> items) {
        this.items = items;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }
}

OrdersItem 订单项 实体类

package com.shore.entity;

/**
 * @author DSHORE/2019-4-26
 *
 */
//对应购物车中的购物项
public class OrdersItem {
    private String id;
    private int num;
    private float price;
    private Book book;
    
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public int getNum() {
        return num;
    }
    public void setNum(int num) {
        this.num = num;
    }
    public float getPrice() {
        return price;
    }
    public void setPrice(float price) {
        this.price = price;
    }
    public Book getBook() {
        return book;
    }
    public void setBook(Book book) {
        this.book = book;
    }
}

2.3、接口和实现类

OrderDao接口

package com.shore.dao;

import java.util.List;

import com.shore.entity.Orders;
import com.shore.entity.User;

/**
 * @author DSHORE/2019-4-26
 *
 */
public interface OrderDao {
    //前台内容
    void addOrders(Orders orders, User user);//添加订单信息（即：用户付款后，将该信息添加到我的订单中）
    List<Orders> findOrdersByUsersId(String id);//根据用户的id查询属于自己的订单
    Orders findOrdersById(String ordersId);//根据id查看订单的详细信息

    //后台订单发货处理
    List<Orders> findOrdersByState(int i);//显示所有未发货的订单,还要查询出是哪个用户的
    void sureOrders(String ordersId);//把已寄出的商品，改成已发货状态
}

OrderDaoImpl 接口的实现类

package com.shore.dao.impl;

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

import com.shore.dao.OrderDao;
import com.shore.entity.Book;
import com.shore.entity.Orders;
import com.shore.entity.OrdersItem;
import com.shore.entity.User;
import com.shore.util.IdGeneratorKey;
import com.shore.util.JdbcUtil;

/**
 * @author DSHORE/2019-4-26
 *
 */
public class OrderDaoImpl implements OrderDao {
    Connection connection = null;
    PreparedStatement pStatement = null;
    ResultSet resultSet = null;
    
    //添加订单信息（即：用户付款后，将该信息添加到我的订单中。即 ：保存到数据库的订单表中）
    public void addOrders(Orders orders, User user) {
        connection = JdbcUtil.getConnection();
        try {
            String sql = "insert into orders (id,orderId,num,price,state,user_id) values(?,?,?,?,?,?);";
            pStatement = connection.prepareStatement(sql);
            //String orderId = IdGeneratorKey.genOrdersId();
            //String ids = IdGeneratorKey.getPrimaryKey();//这两个都不需要，直接从实体类中获取（servlet获取页面中的值，已经存到实体类中了）
            pStatement.setString(1,orders.getId());
            pStatement.setString(2,orders.getOrderId());
            pStatement.setInt(3,orders.getNum());
            pStatement.setFloat(4,orders.getPrice());
            pStatement.setInt(5,orders.getState());
            pStatement.setString(6,user.getId());
            pStatement.executeUpdate();
            //订单中的订单项
            List<OrdersItem> items = orders.getItems();
            if(items != null && items.size() > 0){//订单项中 有东西，才添加进数据库中的订单项表
                String sql2 = "insert into ordersitem (id,num,price,orders_id,book_id) values(?,?,?,?,?)";
                pStatement = connection.prepareStatement(sql2);
                Object pps[][] = new Object[items.size()][];
                for(int i = 0; i < items.size(); i++){
                    String id = IdGeneratorKey.getPrimaryKey();
                    OrdersItem item = items.get(i);
                    pStatement.setString(1,id);
                    pStatement.setInt(2,item.getNum());
                    pStatement.setFloat(3,item.getPrice());
                    pStatement.setString(4,orders.getId());
                    pStatement.setString(5,item.getBook().getId());
                    pStatement.executeUpdate();
                }
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }finally{
            JdbcUtil.close(connection, pStatement, resultSet);
        }
    }

    //根据用户的id查询属于自己的订单
    public List<Orders> findOrdersByUsersId(String id) {
        connection = JdbcUtil.getConnection();
        try {
            pStatement = connection.prepareStatement("select * from orders where user_id=? order by orderId desc;");
            pStatement.setString(1,id);
            resultSet = pStatement.executeQuery();
            List<Orders> list=new ArrayList<Orders>();
            Orders order = null;
            while(resultSet.next()){
                //创建Orders对象
                order = new Orders();
                order.setId(resultSet.getString("id"));
                order.setOrderId(resultSet.getString("orderId"));
                order.setNum(resultSet.getInt("num"));
                order.setState(resultSet.getInt("state"));
                order.setPrice(resultSet.getFloat("price"));
                //order.setUser(rs.getString("user_id"));
                list.add(order);
            }
            return list;
        } catch (SQLException e) {
            e.printStackTrace();
            throw new RuntimeException();
        }finally{
            JdbcUtil.close(connection, pStatement, resultSet);
        }
    }

    //根据id查看订单的详细信息（订单明细、图书明细、当前用户，都要查询出来）
    public Orders findOrdersById(String ordersId) {
        connection = JdbcUtil.getConnection();
        try {
            pStatement = connection.prepareStatement("select * from orders where id=?");
            pStatement.setString(1,ordersId);
            resultSet = pStatement.executeQuery();
            Orders orders = null;
            while(resultSet.next()){
                //创建Orders对象
                orders = new Orders();
                orders.setId(resultSet.getString("id"));
                orders.setOrderId(resultSet.getString("orderId"));
                orders.setNum(resultSet.getInt("num"));
                orders.setState(resultSet.getInt("state"));
                orders.setPrice(resultSet.getFloat("price"));
                //orders.setUser(rs.getString("user_id"));
            }
            if(orders != null){
                //查询用户信息:少的一方，不管有没有需求，默认都是查出来的
                pStatement = connection.prepareStatement("select * from Users where id=(select user_id from orders where id=?)");
                pStatement.setString(1,ordersId);
                resultSet = pStatement.executeQuery();
                User user = null;
                while(resultSet.next()){
                    //创建User对象
                    user = new User();
                    user.setId(resultSet.getString("id"));
                    user.setUserName(resultSet.getString("userName"));
                    user.setPassWord(resultSet.getString("passWord"));
                    user.setCellPhone(resultSet.getString("cellPhone"));
                    user.setMobilePhone(resultSet.getString("mobilePhone"));
                    user.setAddress(resultSet.getString("address"));
                    user.setEmail(resultSet.getString("email"));
                }
                orders.setUser(user);
                //订单明细
                pStatement = connection.prepareStatement("select * from ordersitem where orders_id=?");
                pStatement.setString(1,ordersId);
                resultSet = pStatement.executeQuery();
                List<OrdersItem> items=new ArrayList<OrdersItem>();
                OrdersItem or=null;
                while(resultSet.next()){
                    or=new OrdersItem();
                    or.setId(resultSet.getString("id"));
                    or.setNum(resultSet.getInt("num"));
                    or.setPrice(resultSet.getFloat("price"));
                    items.add(or);
                }
                //查询图书的信息
                if(items != null && items.size() > 0){
                    pStatement = connection.prepareStatement(("select * from Book where id=(select book_id from ordersitem where id=?)"));
                    for(OrdersItem item:items){
                        pStatement.setString(1,item.getId());
                        resultSet = pStatement.executeQuery();
                        Book book = null;
                        while(resultSet.next()){
                            book = new Book();
                            book.setId(resultSet.getString("id"));
                            book.setName(resultSet.getString("name"));
                            book.setAuthor(resultSet.getString("author"));
                            book.setPrice(resultSet.getFloat("price"));
                            book.setImage(resultSet.getString("image"));
                            book.setDescription(resultSet.getString("description"));
                            book.setCategory_id(resultSet.getString("category_id"));
                            item.setBook(book);
                        }
                    }
                }
                orders.setItems(items);
            }
            return orders;
        }catch (SQLException e) {
            e.printStackTrace();
            throw new RuntimeException();
        }finally{
            JdbcUtil.close(connection, pStatement, resultSet);
        }
    }

    //下面几个方法 都是  后台内容   订单发货处理
    //显示所有未发货的订单,还要查询出是哪个用户的
    public List<Orders> findOrdersByState(int i) {
        connection = JdbcUtil.getConnection();
        try {
            pStatement = connection.prepareStatement("select * from orders where state=? order by orderId desc");
            pStatement.setInt(1,i);
            resultSet = pStatement.executeQuery();
            List<Orders> lo = new ArrayList<Orders>();
            Orders order = null;
            while(resultSet.next()){
                order = new Orders();
                order.setId(resultSet.getString("id"));
                order.setOrderId(resultSet.getString("orderId"));
                order.setNum(resultSet.getInt("num"));
                order.setState(resultSet.getInt("state"));
                order.setPrice(resultSet.getFloat("price"));
                //order.setUser(rs.getString("user_id"));
                lo.add(order);
            }
            if(lo != null && lo.size() > 0){
                //查询用户信息:少的一方，不管有没有需求，默认都是查出来的
                pStatement = connection.prepareStatement("select * from Users where id=(select user_id from orders where id=?)");
                for(Orders ord:lo){
                    pStatement.setString(1,ord.getId());
                    resultSet = pStatement.executeQuery();
                    while(resultSet.next()){
                        User user = new User();
                        user.setId(resultSet.getString("id"));
                        user.setUserName(resultSet.getString("userName"));
                        user.setPassWord(resultSet.getString("passWord"));
                        user.setCellPhone(resultSet.getString("cellPhone"));
                        user.setMobilePhone(resultSet.getString("mobilePhone"));
                        user.setAddress(resultSet.getString("address"));
                        user.setEmail(resultSet.getString("email"));
                        ord.setUser(user);
                     }
                }
            }
            return lo;
        } catch (SQLException e) {
            e.printStackTrace();
            throw new RuntimeException();
        }finally{
            JdbcUtil.close(connection, pStatement, resultSet);
        }
    }

    //把已寄出的商品，改成已发货状态
    public void sureOrders(String ordersId) {
        connection = JdbcUtil.getConnection();
        try {
            pStatement = connection.prepareStatement("update orders set state=? where id=?");
            pStatement.setInt(1,1);
            pStatement.setString(2,ordersId);
            pStatement.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }finally{
            JdbcUtil.close(connection, pStatement, resultSet);
        }
    }
}

2.4、Servlet 控制器

ClientServlet 类

package com.shore.web.controller.client;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.shore.entity.Cart;
import com.shore.entity.CartItem;
import com.shore.entity.Orders;
import com.shore.entity.OrdersItem;
import com.shore.entity.User;
import com.shore.service.OrderService;
import com.shore.service.impl.OrderServiceImpl;
import com.shore.util.IdGeneratorKey;

/**
 * @author DSHORE/2019-5-12
 *
 */
public class ClientServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;//序列化
    OrderService oService = new OrderServiceImpl();
    
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String operation = request.getParameter("operation");
        if ("genOrders".equals(operation)) {
            genOrders(request,response);
        }else if ("showUsersOrders".equals(operation)) {
            showUsersOrders(request,response);
        }else if ("showOrdersDetail".equals(operation)) {
            showOrdersDetail(request,response);
        }
    }

    //查看订单的详细信息
    private void showOrdersDetail(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        String ordersId = request.getParameter("ordersId");//取得订单的id（订单号）
        Orders ordersDetail = oService.findOrdersById(ordersId);//订单的明细还要查出来;明细中还要查询出书的信息
        request.setAttribute("ordersDetail", ordersDetail);
        request.getRequestDispatcher("/client/showOrdersDetail.jsp").forward(request, response);
    }

    //根据用户的id查询属于自己的订单
    private void showUsersOrders(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        //判断用户是否登录：如果还没登录，则转向登录页面
        HttpSession session = request.getSession();
        User user = (User)session.getAttribute("user");
        if(user == null){
            request.setAttribute("message", "请先登录，2秒后将自动跳转到登录页面！<meta http-equiv='Refresh' content='2;URL="+request.getContextPath()+"/client/login.jsp'>");
            request.getRequestDispatcher("/client/message.jsp").forward(request, response);
            return;
        }
        List<Orders> UserOrders = oService.findOrdersByUsersId(user.getId());//查询某个用户的所有订单
        request.setAttribute("UserOrders", UserOrders);
        request.getRequestDispatcher("/client/listOrders.jsp").forward(request, response);
    }

    //付款购买：把订单和订单项的信息存入数据库中（生成订单）
    private void genOrders(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        //判断用户是否登录：如果还没登录，则转向登录页面
        HttpSession session = request.getSession();
        User user = (User)session.getAttribute("user");
        if(user == null){
            request.setAttribute("message", "请先登录，2秒后将自动跳转到登录页面！<meta http-equiv='Refresh' content='2;URL="+request.getContextPath()+"/client/login.jsp'>");
            request.getRequestDispatcher("/client/message.jsp").forward(request, response);
            return;
        }
        String id = IdGeneratorKey.getPrimaryKey();//（UUID）自动生成：订单id
        String ordersId = IdGeneratorKey.genOrdersId();//自动生成：订单号
        //如果已登录，则从session中取出购物车中商品：Cart  Map<String,CartItem>  填充模型
        Cart cart = (Cart) session.getAttribute("cart");//购物车
        Orders orders = new Orders();//订单
        orders.setId(id);
        orders.setNum(cart.getNum());
        orders.setPrice(cart.getPrice());
        orders.setState(0);
        orders.setOrderId(ordersId);
        //购物项
        List<OrdersItem> ordersItems = new ArrayList<OrdersItem>();
        for(Map.Entry<String,CartItem> item:cart.getItems().entrySet()){
            CartItem cartItem = item.getValue();
            String orderItemId = IdGeneratorKey.getPrimaryKey();
            OrdersItem orderItem = new OrdersItem();
            //修改
            orderItem.setId(orderItemId);
            orderItem.setNum(cartItem.getNum());
            orderItem.setPrice(cartItem.getPrice());
            orderItem.setBook(cartItem.getBook());
            ordersItems.add(orderItem);
        }
        orders.setItems(ordersItems);
        oService.addOrders(orders,user);
        session.removeAttribute("cart");//付款后，清空session中的购物车
        request.setAttribute("message", "付款成功，请等待店家发货！<span style='font-size: 18px;'><br/><br/>也可点击“我的订单”，查看您的订单信息</span>");//中间的付款步骤没写，这里只是模拟了购物的流程
        request.getRequestDispatcher("/client/message.jsp").forward(request, response);
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
}

2.5、前端页面

listOrders.jsp 主页面

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@include file="/client/header.jsp"%>
<style> 
    table tr th{ border:1px solid #C1C1C1; font-size: 16px;}
    table,table tr td { border:1px solid #C1C1C1; }
    table {  71%; min-height: 25px; line-height: 25px; border-collapse: collapse; padding:2px; margin:auto;text-align: center;}
</style> 

<h2 style="text-align: center;font-size: 20px">以下是您近期的订单</h2>
<table>
       <tr>
           <th>订单号</th>
           <th>金额</th>
           <th>订单状态</th>
           <th>订单详情</th>
       </tr>
       <c:forEach items="${UserOrders}" var="uo">
        <tr>
             <td>${uo.orderId}</td>
             <td>￥${uo.price}元</td>
             <td>${uo.state==0?'未发货':'已发货'}</td>
             <td>
                 <a href="${pageContext.request.contextPath}/ClientServlet?operation=showOrdersDetail&ordersId=${uo.id}">查看明细</a>
             </td>
         </tr>
    </c:forEach>
</table>

showOrdersDetail.jsp 明细页面

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@include file="/client/header.jsp"%>
<style> 
    table tr th{ border:1px solid #C1C1C1; font-size: 16px;}
    table,table tr td { border:1px solid #C1C1C1; }
    table {  71%; min-height: 25px; line-height: 25px; border-collapse: collapse; padding:2px; margin:auto;text-align: center;}
</style> 

<div style="font-size: 15px;">
    订单号：${ordersDetail.orderId}&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
    总金额：￥${ordersDetail.price}元&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;明细如下：<br/>
</div>
<table>
    <tr>
        <th>书名</th>
        <th>作者</th>
        <th>单价</th>
        <th>数量</th>
        <th>小计</th>
    </tr>
    <c:forEach items="${ordersDetail.items}" var="od">
        <tr>
            <td>${od.book.name}1</td>
            <td>${od.book.author}</td>
            <td>￥${od.book.price}元</td>
            <td>${od.num }</td>
            <td>￥${od.price}元</td>
        </tr>
    </c:forEach>
</table>
<div style="text-align:left;280px; margin:0 auto;font-size: 15px;">
    收货信息如下：<br/>
    地址：${ordersDetail.user.address }<br/>
    电话：${ordersDetail.user.cellPhone }<br/>
</div>    

把商品加入购物车中及删除操作（Servlet技术，简单演示）

 

原创作者：DSHORE

作者主页：http://www.cnblogs.com/dshore123/

原文出自：https://www.cnblogs.com/dshore123/p/10775869.html

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