add<购物车列表>

src/main/java/example/controller/CartServlet.java

@@ -0,0 +1,52 @@
+package example.controller;
+
+import example.model.Computer;
+import example.service.ICartService;
+import example.service.impl.CartServiceImpl;
+
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.util.List;
+
+@WebServlet("/cart")
+public class CartServlet extends HttpServlet {
+
+    ICartService cartService = new CartServiceImpl();
+
+    @Override
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+        String action = req.getParameter("action");
+        switch (action){
+            case "list":
+                try {
+                    toCart(req, resp);
+                } catch (Exception e) {
+                    throw new RuntimeException(e);
+                }
+                break;
+            case "add":
+                String id = req.getParameter("id");
+                req.getSession().setAttribute("cart",id);
+                resp.sendRedirect("/cart");
+                break;
+            case "remove":
+                String removeId = req.getParameter("id");
+                req.getSession().removeAttribute(removeId);
+                resp.sendRedirect("/cart");
+                break;
+            default:
+                req.getRequestDispatcher("/WEB-INF/jsp/cart.jsp").forward(req,resp);
+                break;
+        }
+    }
+
+    private void toCart(HttpServletRequest req, HttpServletResponse resp) throws Exception {
+        List<Computer> computers = cartService.myCart(16);
+        req.setAttribute("computers",computers);
+        req.getRequestDispatcher("cart.jsp").forward(req,resp);
+    }
+}

src/main/java/example/dao/CartDao.java

@@ -0,0 +1,37 @@
+package example.dao;
+
+import example.model.Computer;
+import example.utils.DBUtils;
+import org.apache.commons.dbutils.QueryRunner;
+import org.apache.commons.dbutils.handlers.BeanListHandler;
+
+import java.util.List;
+
+public class CartDao {
+    private final QueryRunner queryRunner = new QueryRunner(DBUtils.getDataSource());
+
+//    加入购物车
+    public int addCart(Integer user_id, Integer product_id) throws Exception {
+        String sql = "insert into cart(user_id, product_id) values(?,?)";
+        return queryRunner.update(sql, user_id, product_id);
+    }
+//   移除购物车
+    public int deleteCart(Integer user_id, Integer product_id) throws Exception {
+        String sql = "delete from cart where user_id=? and product_id=?";
+        return queryRunner.update(sql, user_id, product_id);
+    }
+//    某用户的购物车
+    public List<Computer> getCart(Integer user_id) throws Exception {
+        String sql = "select\n" +
+                "\tc2.*\n" +
+                "from\n" +
+                "\tcart c\n" +
+                "left join computer c2 \n" +
+                "on\n" +
+                "\tc.product_id = c2.id\n" +
+                "where\n" +
+                "\tc.user_id = ?";
+        return queryRunner.query(sql,new BeanListHandler<>(Computer.class),user_id);
+    }
+
+}

src/main/java/example/model/Cart.java

@@ -0,0 +1,10 @@
+package example.model;
+
+public class Cart {
+    private Integer id;
+
+    private Integer userId;
+
+    private Integer productId;
+
+}

src/main/java/example/service/ICartService.java

@@ -0,0 +1,9 @@
+package example.service;
+
+import example.model.Computer;
+
+import java.util.List;
+
+public interface ICartService {
+    List<Computer> myCart(Integer userId) throws Exception;
+}

src/main/java/example/service/impl/CartServiceImpl.java

@@ -0,0 +1,18 @@
+package example.service.impl;
+
+import example.dao.CartDao;
+import example.model.Computer;
+import example.service.ICartService;
+
+import java.util.Collections;
+import java.util.List;
+
+public class CartServiceImpl implements ICartService {
+
+    CartDao cartDao = new CartDao();
+
+    @Override
+    public List<Computer> myCart(Integer userId) throws Exception {
+        return cartDao.getCart(userId);
+    }
+}

src/main/webapp/cart.jsp

@@ -0,0 +1,38 @@
+<%@ page contentType="text/html; charset=UTF-8" language="java" %>
+<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>购物车</title>
+</head>
+<body>
+    <h1>购物车</h1>
+    <table border="1">
+        <thead>
+            <tr>
+                <th>ID</th>
+                <th>Name</th>
+                <th>Price</th>
+                <th>Actions</th>
+            </tr>
+        </thead>
+        <tbody>
+            <c:forEach var="computer" items="${computers}">
+                <tr>
+                    <td>${computer.id}</td>
+                    <td>${computer.name}</td>
+                    <td>${computer.price}</td>
+                    <td>
+                        <a href="/deleteComputer?id=${computer.id}">移出</a>
+                    </td>
+                </tr>
+            </c:forEach>
+        </tbody>
+    </table>
+    <br/>
+    <br>
+    <a href="/">主页</a>
+</body>
+</html>

src/main/webapp/index.jsp

@@ -8,5 +8,6 @@
 <a href="/login">登录</a>
 <a href="/computerList">电脑列表</a>
 <a href="/user?action=list">用户列表</a>
+<a href="/cart?action=list">我的购物车</a>
 </body>
 </html>