使用session对购物车的简单实现（oracle数据库+数据源）
实现购物车，有很多的方法，我这次用的session，使用oracle数据库来存取数据
1、数据库设计（就一个表：商品表 items），并插入几条测试数据
2、利用MVC的思想来设计整个项目的结构，如下所示
3、首先设计po包，主要有：Items.java Cart.java
package cn.hpe.po;
/**
* 商品实体类
* @author CCQ
* @date 2016年9月17日
*/
public class Items {
private String pid; //商品编号
private String pname;//商品名称
private String city;//产地
private double price;//价格
private int pnum;//库存
private String pic;//商品图片
//保留此不带参数的构造方法
public Items(){
}
//带参数的构造方法
public Items(String pid, String pname, String city, double price, int pnum,
String pic) {
this.pid = pid;
this.pname = pname;
this.city = city;
this.price = price;
this.pnum = pnum;
this.pic = pic;
}
public String getPid() {
return pid;
}
public void setPid(String pid) {
this.pid = pid;
}
public String getPname() {
return pname;
}
public void setPname(String pname) {
this.pname = pname;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
public int getPnum() {
return pnum;
}
public void setPnum(int pnum) {
this.pnum = pnum;
}
public String getPic() {
return pic;
}
public void setPic(String pic) {
this.pic = pic;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((pid == null) ? 0 : pid.hashCode());
result = prime * result + ((pname == null) ? 0 : pname.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (!(obj instanceof Items))
return false;
Items other = (Items) obj;
if (pid == null) {
if (other.pid != null)
return false;
} else if (!pid.equals(other.pid))
return false;
if (pname == null) {
if (other.pname != null)
return false;
} else if (!pname.equals(other.pname))
return false;
return true;
}
}
package cn.hpe.po;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
/**
* 购物车实体（添加、删除和计算价格）
*
* @author CCQ
* @date 2016年9月17日
*/
public class Cart {
private HashMap goods; // 购买的商品集合
private double totalPrice; // 购物车的总金额
// 构造方法
public Cart() {
goods = new HashMap();
totalPrice = 0;
}
public HashMap getGoods() {
return goods;
}
public void setGoods(HashMap goods) {
this.goods = goods;
}
public double getTotalPrice() {
return totalPrice;
}
public void setTotalPrice(double totalPrice) {
this.totalPrice = totalPrice;
}
// 添加商品进购物车的方法
public boolean addGoodsInCart(Items item, int number) {
if (goods.containsKey(item)) {
goods.put(item, goods.get(item) + number);
} else {
goods.put(item, number);
}
calTotalPrice(); // 重新计算购物车的总金额
return true;
}
// 统计购物车的总金额
public double calTotalPrice() {
double sum = 0;
Set keys = goods.keySet(); // 获得键的集合
Iterator it = keys.iterator(); // 获得迭代器的对象
while (it.hasNext()) {
Items i = it.next();
sum += i.getPrice() * goods.get(i);
}
this.setTotalPrice(sum); // 设置购物车的总金额
return this.getTotalPrice();
}
// 删除商品的方法
public boolean removeGoodsFromCart(Items item) {
goods.remove(item);
calTotalPrice();// 重新计算购物车总金额
return true;
}
//测试购物车的添加和计算总的金额
public static void main(String[] args) {
// 先创建两个商品对象
Items i1 = new Items("1", "沃特篮球鞋", "温州", 200, 500, "001.jpg");
Items i2 = new Items("2", "李宁运动鞋", "广州", 300, 500, "002.jpg");
Items i3 = new Items("1", "沃特篮球鞋", "温州", 200, 500, "001.jpg");
Cart c = new Cart();
c.addGoodsInCart(i1, 1);
c.addGoodsInCart(i2, 2);
// 再次购买沃特篮球鞋，购买3双
c.addGoodsInCart(i3, 3);
// 变量购物商品的集合
Set> items = c.getGoods().entrySet();
for (Map.Entry obj : items) {
System.out.println(obj);
}
Set keys = c.getGoods().keySet(); // 获得键的集合
Iterator it = keys.iterator(); // 获得迭代器的对象
while (it.hasNext()) {
Items i = it.next();
System.out.println(i.getPname()+"=="+c.getGoods().get(i));
}
System.out.println("购物车的总金额：" + c.getTotalPrice());
}
}
然后有添加到购物车的方法（addGoodsInCart(Items item, int number)）
把物品从购物车中移除方法（removeGoodsFromCart(Items item)）
计算购物车总的金额方法（calTotalPrice()）
其中在向购物车中添加商品时，用到了containsKey()方法，其本质是比较hashCode是否相等，所以在Items中必须重写equals和hashCode方法
4、编写数据访问层dao：主要是对商品的处理IItemsDao()接口和它的实现类ItemsDaoImpl()
package cn.hpe.dao.interfaces;
import java.util.List;
import cn.hpe.po.Items;
public interface IItemsDao {
/**
* 查询所有的商品
* @return
* @throws Exception
*/
public List getAllItems() throws Exception;
/**
* 根据商品id查询商品
* @param pid
* @return
* @throws Exception
*/
public Items getItemById(String pid) throws Exception;
}
package cn.hpe.dao.impl;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import cn.hpe.dao.config.BaseDao;
import cn.hpe.dao.interfaces.IItemsDao;
import cn.hpe.po.Items;
/**
* 商品操作实现类
* @author CCQ
* @date 2016年9月17日
*/
public class ItemsDaoImpl implements IItemsDao {
@Override
public List getAllItems() throws Exception {
// TODO Auto-generated method stub
List items = null;
BaseDao baseDao = new BaseDao();
try{
Connection conn = baseDao.getConnection();
String sql = "select * from items";
PreparedStatement ps = conn.prepareStatement(sql);
ResultSet rs = ps.executeQuery();
items = new ArrayList();
while(rs.next()){
Items item = new Items();
item.setPid(rs.getString("pid"));
item.setPname(rs.getString("pname"));
item.setCity(rs.getString("city"));
item.setPnum(rs.getInt("pnum"));
item.setPrice(rs.getDouble("price"));
item.setPic(rs.getString("pic"));
items.add(item);
}
baseDao.closeConn(rs, ps, conn);
}catch(Exception e){
throw new Exception(e);
}
return items;
}
@Override
public Items getItemById(String pid) throws Exception {
// TODO Auto-generated method stub
Items item = null;
BaseDao baseDao = new BaseDao();
try{
Connection conn = baseDao.getConnection();
String sql = "select * from items where pid = ?";
PreparedStatement ps = conn.prepareStatement(sql);
ps.setObject(1, pid);
ResultSet rs = ps.executeQuery();
if(rs.next()){
item = new Items();
item.setPid(rs.getString("pid"));
item.setPname(rs.getString("pname"));
item.setCity(rs.getString("city"));
item.setPnum(rs.getInt("pnum"));
item.setPrice(rs.getDouble("price"));
item.setPic(rs.getString("pic"));
}
baseDao.closeConn(rs, ps, conn);
}catch(Exception e){
throw new Exception(e);
}
return item;
}
}
还有就是baseDao，其中使用数据源实现和数据库的链接，需要在tomcat中配置一下数据源
package cn.hpe.dao.config;
import java.sql.*;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.sql.DataSource;
/**
* 连接oracle数据库类，使用连接池的方法
*
* @author CCQ
*
*/
public class BaseDao {
public Connection getConnection() throws Exception {
System.out.println("开始使用连接池...");
Connection conn = null;
try {
Context context = new InitialContext();
DataSource ds = (DataSource) context
.lookup("java:comp/env/jdbc/gm");
conn = ds.getConnection();
} catch (Exception e) {
throw new Exception(e);
}
return conn;
}
/**
* 关闭数据库连接
*/
public void closeConn(ResultSet rs, PreparedStatement ps, Connection conn)
throws Exception {
try {
if (rs != null) {
rs.close();
}
if (ps != null) {
ps.close();
}
if (conn != null) {
conn.close();
}
} catch (Exception ex) {
throw new Exception(ex);
}
}
}
5、在书写services包，注意异常向外抛，最后在servlet中在进行处理
package cn.hpe.services.interfaces;
import java.util.List;
import cn.hpe.po.Items;
public interface IItemsService {
/**
* 查询所有的商品
* @return
* @throws Exception
*/
public List getAllItems() throws Exception;
/**
* 根据商品id查询商品
* @param pid
* @return
* @throws Exception
*/
public Items getItemById(String pid) throws Exception;
}
package cn.hpe.services.impl;
import java.util.List;
import cn.hpe.dao.impl.ItemsDaoImpl;
import cn.hpe.dao.interfaces.IItemsDao;
import cn.hpe.po.Items;
import cn.hpe.services.interfaces.IItemsService;
public class ItemsServiceImpl implements IItemsService{
@Override
public List getAllItems() throws Exception {
// TODO Auto-generated method stub
IItemsDao itemsDao = new ItemsDaoImpl();
List items = null;
try{
items = itemsDao.getAllItems();
}catch(Exception e){
throw new Exception(e);
}
return items;
}
@Override
public Items getItemById(String pid) throws Exception {
// TODO Auto-generated method stub
IItemsDao itemsDao = new ItemsDaoImpl();
Items item = null;
try{
item = itemsDao.getItemById(pid);
}catch(Exception e){
throw new Exception(e);
}
return item;
}
}
6、数据控制层：servlet的书写，主要有商品控制：ItemsServlet和CartServlet
package cn.hpe.action;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cn.hpe.po.Items;
import cn.hpe.services.impl.ItemsServiceImpl;
import cn.hpe.services.interfaces.IItemsService;
public class ItemsServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
IItemsService itemsService = new ItemsServiceImpl();
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
this.doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
String op = request.getParameter("option");
if ("list".equals(op)) {
itemList(request, response);
}
if ("item".equals(op)) {
itemDetails(request, response);
}
}
// 显示所有的商品
public void itemList(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
try {
List items = new ArrayList();
items = itemsService.getAllItems();
request.setAttribute("items", items);
request.getRequestDispatcher("index.jsp")
.forward(request, response);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
// 显示商品的详细信息
public void itemDetails(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
try {
String pid = request.getParameter("pid");
Items item = new Items();
item = itemsService.getItemById(pid);
request.setAttribute("item", item);
request.getRequestDispatcher("details.jsp")
.forward(request, response);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
package cn.hpe.action;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cn.hpe.po.Cart;
import cn.hpe.po.Items;
import cn.hpe.services.impl.ItemsServiceImpl;
import cn.hpe.services.interfaces.IItemsService;
/**
* 购物车的Servlet
*
* @author CCQ
* @date 2016年9月17日
*/
public class CartServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
IItemsService itemsService = new ItemsServiceImpl();
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
this.doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
String op = request.getParameter("option");
if ("add".equals(op)) {
addToCart(request, response);
String pid = request.getParameter("pid");
response.sendRedirect("ItemsServlet?pid="+pid+"&option=item");
} else if ("show".equals(op)) {
cartList(request, response);
} else if ("delete".equals(op)) {
deleteFromCart(request, response);
request.getRequestDispatcher("CartServlet?option=show").forward(request, response);
}
}
// 添加商品进购物车
public boolean addToCart(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
try {
String pid = request.getParameter("pid");
int num = Integer.parseInt(request.getParameter("num"));
Items item = itemsService.getItemById(pid);
// 是否是第一次给购物车添加商品时，需要给session中创建一个新的购物车对象
if (request.getSession().getAttribute("cart") == null) {
Cart cart = new Cart();
request.getSession().setAttribute("cart", cart);
}
Cart cart = (Cart) request.getSession().getAttribute("cart");
if (cart.addGoodsInCart(item, num)) {
cart = (Cart) request.getSession().getAttribute("cart");
return true;
} else {
return false;
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return false;
}
// 从购物车删除商品
public boolean deleteFromCart(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
try {
String pid = request.getParameter("pid");
Cart cart = (Cart) request.getSession().getAttribute("cart");
Items item = itemsService.getItemById(pid);
if (cart.removeGoodsFromCart(item)) {
return true;
} else {
return false;
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return false;
}
// 显示购物车
public void cartList(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
Cart cartMap = (Cart) request.getSession().getAttribute("cart");
request.setAttribute("cartMap", cartMap);
request.getRequestDispatcher("cartList.jsp").forward(request, response);
}
}
7、最后的就是前台JSP页面的设计，我的设计就是简单地排版，哈哈
（1）商品显示主页面 index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
商品展示页面
商品展示
-
- ${item.pname }
- 产地:${item.city }
- 价格:￥${item.price }
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
商品详细信息页面
商品详情
首页 >>
商品列表
${item.pname }
产地：${item.city }
价格：￥${item.price }
购买数量：- +
（3）显示购物车 cartList.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
购物车
我的购物车
首页 >>
商品列表
商品名称
商品单价
商品价格
购买数量
操作
${c.key.pname }${c.key.price }元
${c.key.price*c.value }元
${c.value }件
删除
总计：${cartMap.totalPrice}元
8、项目运行结果展示
