技术教程 史上功能最全Web购物车实现（基于jsp+java+servlet+dao）包括后台图书管理、实现数据库分页等功能 正文

史上功能最全Web购物车实现（基于jsp+java+servlet+dao）包括后台图书管理、实现数据库分页等功能

2022-07-26,,,,

购物车实现

  • 基本功能描述
    • 页面展示
    • 购物车数据库信息
    • 代码路径展示
    • 代码实现
    • bean基本属性的配置
        • dao路径下对数据库进行的处理
        • 首页代码
        • BookServlet逻辑处理
        • 主页面展示页面
        • cart.jsp购物车信息展示
        • 图书后台信息管理

基本功能描述

本项目实现的是一个可视化的购物车系统，其主要功能如下。

  • 用户进入登录页面进行登录，登陆成功则跳转到购物车主页面。由于登录页面在前一篇博客中已说明，本篇博客不再赘述，有需要者可以在此链接中查看：https://blog.csdn.net/qq_43505820/article/details/109562912。
  • 通过连接数据库显示图书信息，用户可以选择要加入购物车的物品数量，所加入的物品信息在我的购物车中即可查看。
  • 我的购物车中对所加入购物车的商品进行查看，同时可进行数量修改和删除，清空购物车等功能。
  • 图书管理页面是对数据库中的商品信息的展示，可以添加图书，也可以对价格，售卖情况等信息进行修改添加删除等，实现基本的增删改查操作。
  • 购物车和图书管理都实现了分页功能（数据过多无法在一个页面显示，可使用分页功能使其可视化更强。）
    （备注：读者在实现功能的时候可以将其细化，比如用户只能进入购物车页面无法查看后台的图书数据，只有管理员才能进入图书管理系统）

页面展示

购物车主页面

我的购物车页面展示

图书管理页面

购物车数据库信息

本项目使用的是mysql:建表如下：

CREATE TABLE `shopbook` (                                                                                                                                                                                                                                                                                                                                               
            `id` int(11) NOT NULL AUTO_INCREMENT,                                                                                                                                                                                                                                                                                                                                 
            `name1` varchar(100) DEFAULT NULL,                                                                                                                                                                                                                                                                                                                                    
            `author` varchar(100) DEFAULT NULL,                                                                                                                                                                                                                                                                                                                                   
            `price` decimal(11,2) DEFAULT NULL,                                                                                                                                                                                                                                                                                                                                   
            `sales` int(11) DEFAULT NULL,                                                                                                                                                                                                                                                                                                                                         
            `stock` int(11) DEFAULT NULL,                                                                                                                                                                                                                                                                                                                                         
            `img_path` varchar(200) DEFAULT NULL,                                                                                                                                                                                                                                                                                                                                 
            PRIMARY KEY (`id`)                                                                                                                                                                                                                                                                                                                                                    
          ) ENGINE=InnoDB AUTO_INCREMENT=27 DEFAULT CHARSET=utf8

具体数据请自己进行添加。

代码路径展示

代码实现

bean基本属性的配置

Books属性：

package bean;

import java.math.BigDecimal;

public class Books {
    private Integer id;
    private String name1;
    private String author;
    private BigDecimal price;
    private Integer sales;//出售量
    private Integer stock;//库存量
    //默认图片路径
    private String imgPath="img/6f99aa07366c5fb5.jpg";
    public Books(){}
    public Books(Integer id, String name, String author, BigDecimal price, Integer sales, Integer stock, String imgPath) {
        this.id = id;
        this.name1 = name;
        this.author = author;
        this.price = price;
        this.sales = sales;
        this.stock = stock;
        if(imgPath!=null&&!"".equals(imgPath)) {
            this.imgPath = imgPath;
        }
    }

    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name1;
    }

    public void setName(String name) {
        this.name1 = name;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public BigDecimal getPrice() {
        return price;
    }

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

    public Integer getSales() {
        return sales;
    }

    public void setSales(Integer sales) {
        this.sales = sales;
    }

    public Integer getStock() {
        return stock;
    }

    public void setStock(Integer stock) {
        this.stock = stock;
    }

    public String getImgPath() {
        return imgPath;
    }

    public void setImgPath(String imgPath) {
        if(imgPath!=null&&!"".equals(imgPath)) {
            this.imgPath = imgPath;
        }
    }

    @Override
    public String toString() {
        return "Books{" +
                "id=" + id +
                ", name='" + name1 + '\'' +
                ", author='" + author + '\'' +
                ", price=" + price +
                ", sales=" + sales +
                ", stock=" + stock +
                ", imgPath='" + imgPath + '\'' +
                '}';
    }
}

Cart:

package bean;

import java.math.BigDecimal;
import java.util.LinkedHashMap;
import java.util.Map;

public class Cart{
   // private Integer totalCount;
   // private BigDecimal totalPrice;
    private Map<Integer,CartItem> items=new LinkedHashMap<>();
    public Cart(){}
    @Override
    public String toString() {
        return "Cart{" +
                "totalCount=" + getTotalCount() +
                ", totalPrice=" + getTotalPrice() +
                ", items=" + items +
                '}';
    }
    //通过map进行遍历
    public Integer getTotalCount() {
        Integer totalCount=0;
        for(Map.Entry<Integer,CartItem> entry:items.entrySet()){
            totalCount+=entry.getValue().getCount();
        }
        return totalCount;
    }

    public BigDecimal getTotalPrice() {
        BigDecimal totalPrice=new BigDecimal(0);
        for(Map.Entry<Integer,CartItem> entry:items.entrySet()){
            totalPrice=totalPrice.add(entry.getValue().getTotalPrice());
        }
        return totalPrice;
    }

    public Map<Integer,CartItem> getItems() {
        return items;
    }

    public void setItems(Map<Integer,CartItem> items) {
        this.items = items;
    }
    //添加商品
    public void addItem(CartItem cartItem){
        //获取到cartItem的ID 对他的属性进行添加
        CartItem item = items.get(cartItem.getId());
        items.put(cartItem.getId(),cartItem);
    }
    public void deleteItem(Integer id){
      items.remove(id);
    }
    //清空购物车
    public void clear(){
     items.clear();
    }
    //修改商品数量
    public void updateCount(Integer id,Integer count){
     //先查看购物车中是否有该商品，有则修改商品数量
        CartItem cartItem = items.get(id);
        if(cartItem!=null){
            cartItem.setCount(count);
            cartItem.setTotalPrice(cartItem.getPrice().multiply(new BigDecimal(cartItem.getCount())));
        }
    }

}

CartItem:

package bean;

import java.math.BigDecimal;

public class CartItem {
    private Integer id;
    private String name;
    private Integer count;
    private BigDecimal price;
    private BigDecimal totalPrice;
   public CartItem(){}

    public CartItem(Integer id, String name, Integer count, BigDecimal price, BigDecimal totalPrice) {
        this.id = id;
        this.name = name;
        this.count = count;
        this.price = price;
        this.totalPrice = totalPrice;
    }

    @Override
    public String toString() {
        return "CartItem{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", count=" + count +
                ", price=" + price +
                ", totalPrice=" + totalPrice +
                '}';
    }

    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getCount() {
        return count;
    }

    public void setCount(Integer count) {
        this.count = count;
    }

    public BigDecimal getPrice() {
        return price;
    }

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

    public BigDecimal getTotalPrice() {
        return totalPrice;
    }

    public void setTotalPrice(BigDecimal totalPrice) {
        this.totalPrice = totalPrice;
    }
}

Page:

package bean;

import java.util.List;

/**
 * 
 * @createTime 2020/11/26 9:17
 * @description
 */

public class Page<T> {
    //每页显示数量
    public static final Integer Page_Size=4;
    //当前页码
    private Integer pageNo;
    //总页码
    private Integer pageTotal;
    private Integer pageSize=Page_Size;
    //总记录数
    private Integer pageTotalCount;
    //当前页数据
    private List<T>  item;
    @Override
    public String toString() {
        return "Page{" +
                "pageNo=" + pageNo +
                ", pageTotal=" + pageTotal +
                ", pageSize=" + pageSize +
                ", pageTotalCount=" + pageTotalCount +
                ", item=" + item +
                '}';
    }
    public static Integer getPage_Size() {
        return Page_Size;
    }
    public Integer getPageNo() {
        return pageNo;
    }
    public void setPageNo(Integer pageNo) {
        this.pageNo = pageNo;
    }
    public Integer getPageTotal() {
        return pageTotal;
    }
    public void setPageTotal(Integer pageTotal) {
        this.pageTotal = pageTotal;
    }
    public Integer getPageSize() {
        return pageSize;
    }
    public void setPageSize(Integer pageSize) {
        this.pageSize = pageSize;
    }
    public Integer getPageTotalCount() {
        return pageTotalCount;
    }
    public void setPageTotalCount(Integer pageTotalCount) {
        this.pageTotalCount = pageTotalCount;
    }
    public List<T> getItem() {
        return item;
    }
    public void setItem(List<T> item) {
        this.item = item;
    }
}

User:

package bean;
public class User {
    private String name;
    private String pd;
    public User(){}
    public String getPd() {
        return pd;
    }
    public void setPd(String pd) {
        this.pd = pd;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

dao路径下对数据库进行的处理

BookDao:

package dao.impl;
import bean.Books;
import java.util.List;
/**
 * @createTime 2020/11/24 14:51
 * @description
 */

public interface BookDao {
    //实现增删改查
    public int addBook(Books book);
    public int deleteBookById(Integer id);
    public int updateBook(Books book);
    public Books queryBookById(Integer id);
    public List<Books> queryBooks();
    public int queryForPageTotalCount();
    public List<Books> queryForPageItems(Integer begin, Integer pageSize);
}

BookDaoImpl

package dao.impl;

import bean.Books;
import bean.Page;

import java.sql.*;
import java.util.LinkedList;
import java.util.List;


//访问数据库  对数据库进行增删改查操作
public class BookDaoImpl implements BookDao {
    PreparedStatement preparedStatement = null;
    ResultSet rs = null;
    Connection con = null;
    //向数据库中添加书
    @Override
    public int addBook(Books book) {
        //启动mysql驱动器
        try {
            Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8", "root", "123456");
            String sql = "insert into shopbook(name1,author,price,sales,stock,img_path) values (?,?,?,?,?,?) ";
            preparedStatement = con.prepareStatement(sql);
            preparedStatement.setString(1, book.getName());
            preparedStatement.setString(2, book.getAuthor());
            preparedStatement.setBigDecimal(3, book.getPrice());
            preparedStatement.setInt(4, book.getSales());
            preparedStatement.setInt(5, book.getStock());
            preparedStatement.setString(6, book.getImgPath());
            preparedStatement.execute();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            if (preparedStatement != null) {
                try {
                    preparedStatement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
        return 1;
    }

    //根据提供书的ID将数据删除
    @Override
    public int deleteBookById(Integer id) {
        //启动mysql驱动器
        try {
            Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8", "root", "123456");
            String sql = "delete from shopbook where id=?";
            preparedStatement = con.prepareStatement(sql);
            preparedStatement.setInt(1, id);
            preparedStatement.executeUpdate();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            if (preparedStatement != null) {
                try {
                    preparedStatement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
        return 1;
    }
//更新书信息
    @Override
    public int updateBook(Books book) {
        //启动mysql驱动器
        try {
            Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8", "root", "123456");
            String sql = "update shopbook set name1=?,author=?,price=?,sales=?,stock=?,img_path=? where id=?";
            preparedStatement = con.prepareStatement(sql);
            preparedStatement.setString(1, book.getName());
            preparedStatement.setString(2, book.getAuthor());
            preparedStatement.setBigDecimal(3, book.getPrice());
            preparedStatement.setInt(4, book.getSales());
            preparedStatement.setInt(5, book.getStock());
            preparedStatement.setString(6, book.getImgPath());
            preparedStatement.setInt(7, book.getId());
            preparedStatement.executeUpdate();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            if (preparedStatement != null) {
                try {
                    preparedStatement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
        return 0;
    }
//通过ID查询到书的信息
    @Override
    public Books queryBookById(Integer id) {
        Books books = new Books();
        //启动mysql驱动器
        try {
            Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8", "root", "123456");
            String sql = "select id,name1,author,price,sales,stock,img_path imgPath from shopbook where id=? ";
            preparedStatement = con.prepareStatement(sql);
            preparedStatement.setInt(1,id);
            rs = preparedStatement.executeQuery();
            while (rs.next()) {
                books.setId(rs.getInt("id"));
                books.setName(rs.getString("name1"));
                books.setAuthor(rs.getString("author"));
                books.setPrice(rs.getBigDecimal("price"));
                books.setSales(rs.getInt("sales"));
                books.setStock(rs.getInt("stock"));
                books.setImgPath(rs.getString("imgPath"));
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            if (preparedStatement != null) {
                try {
                    preparedStatement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
        return books;
    }
//查询所有图书
    @Override
    public List<Books> queryBooks() {
        List<Books> books = new LinkedList<>();
        //启动mysql驱动器
        try {
            Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8", "root", "123456");
            String sql = "select id,name1,author,price,sales,stock,img_path imgPath from shopbook";
            preparedStatement = con.prepareStatement(sql);
            rs = preparedStatement.executeQuery();
            while (rs.next()) {
                Books books1 = new Books();
                books1.setId(rs.getInt("id"));
                books1.setName(rs.getString("name1"));
                books1.setAuthor(rs.getString("author"));
                books1.setPrice(rs.getBigDecimal("price"));
                books1.setSales(rs.getInt("sales"));
                books1.setStock(rs.getInt("stock"));
                books1.setImgPath(rs.getString("imgPath"));
                books.add(books1);
            }

        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            if (preparedStatement != null) {
                try {
                    preparedStatement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
        return books;
    }
//获取所有信息的个数
    @Override
    public int queryForPageTotalCount() {
        Statement statement=null;
        //启动mysql驱动器
        try {
            Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8", "root", "123456");
            String sql = "select * from shopbook";
            statement=con.createStatement();
            ResultSet rs = statement.executeQuery(sql);
            rs.last();
            return rs.getRow();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            if (statement != null) {
                try {
                    statement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
        return 0;
    }
//获取从指定ID和count获取该部分的所有数据信息
    @Override
    public List<Books> queryForPageItems(Integer begin, Integer pageSize) {
        List<Books> books = new LinkedList<>();
        //启动mysql驱动器
        try {
            Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8", "root", "123456");
            String sql = "select id,name1,author,price,sales,stock,img_path imgPath from shopbook limit ?,?";
            preparedStatement = con.prepareStatement(sql);
            preparedStatement.setInt(1,begin);
            preparedStatement.setInt(2,pageSize);
            rs = preparedStatement.executeQuery();
            while (rs.next()) {
                Books books1 = new Books();
                books1.setId(rs.getInt("id"));
                books1.setName(rs.getString("name1"));
                books1.setAuthor(rs.getString("author"));
                books1.setPrice(rs.getBigDecimal("price"));
                books1.setSales(rs.getInt("sales"));
                books1.setStock(rs.getInt("stock"));
                books1.setImgPath(rs.getString("imgPath"));
                books.add(books1);
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            if (preparedStatement != null) {
                try {
                    preparedStatement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
        return books;
    }
}

首页代码

注意首页面代码（使用idea在没有设置默认路径的时候默认启动的是index.jsp页面，可以在此处写入，防止代码过多忘记从哪个页面开始启动）：
index.jsp:

<%@ page contentType="text/html;charset=gb2312" pageEncoding="gb2312" language="java" import="bean.*"
%>
<html>
<head>
    <title>welcome</title>
</head>
<body>
<a href="http://localhost:8080/BookServlet?action=firstPage">进入购物页面</a>
</body>
</html>

BookServlet逻辑处理

BookServlet中的firstPage对商品信息显示进行处理,此类提供的其他方法后面会用到。

package servlet;

import bean.Books;
import bean.Page;
import dao.impl.BookDaoImpl;

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 javax.servlet.http.HttpSession;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.math.BigDecimal;
import java.util.List;

@WebServlet("/BookServlet")
public class BookServlet extends HttpServlet {
     BookDaoImpl bookDao=new BookDaoImpl();
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      doGet(request,response);
    }

    //获取路径中action后要进行的操作
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //中文乱码解决方法
        response.setContentType("text/html;charset=utf-8");
        request.setCharacterEncoding("utf-8");
        String action=request.getParameter("action");
        try {
            Method method = this.getClass().getDeclaredMethod(action, HttpServletRequest.class, HttpServletResponse.class);
            method.invoke(this,request,response);
        }
        catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
    }
    //实现数据的添加操作
    protected void add(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
   //Book类 book的基本属性：包括 ID name author price sales stock imgPath
    Books books=new Books();
     books.setName(request.getParameter("name"));
     books.setAuthor(request.getParameter("author"));
     String price = request.getParameter("price");
         BigDecimal bigDecimal = new BigDecimal(price);
         books.setPrice(bigDecimal);
     books.setSales(Integer.parseInt(request.getParameter("sales")));
     books.setStock(Integer.parseInt(request.getParameter("stock")));
     //访问数据库
     bookDao.addBook(books);
     //跳转到显示数据的页面
     response.sendRedirect(request.getContextPath()+"/BookServlet?action=page");
    }
    //对信息删除
    protected void delete(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String id = request.getParameter("id");
        bookDao.deleteBookById(Integer.parseInt(id));
        response.sendRedirect(request.getContextPath()+"/BookServlet?action=page");
    }

    protected void update(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        HttpSession session=request.getSession();
        String id=(String)session.getAttribute("id");
        Books books=new Books();
        books.setId(Integer.parseInt(id));
        books.setName(request.getParameter("name"));
        books.setAuthor(request.getParameter("author"));
        String price = request.getParameter("price");
        BigDecimal bigDecimal = new BigDecimal(price);
        books.setPrice(bigDecimal);
        books.setSales(Integer.parseInt(request.getParameter("sales")));
        books.setStock(Integer.parseInt(request.getParameter("stock")));
        bookDao.updateBook(books);
        response.sendRedirect(request.getContextPath()+"/BookServlet?action=page");
    }
    protected void list(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    //查询全部图书
        List<Books> books = bookDao.queryBooks();
        HttpSession session=request.getSession();
        //把图书存放在request域中
        session.setAttribute("books",books);
        //请求转发到bookmanage.jsp页面
        request.getRequestDispatcher("jspdemo/bookManage.jsp").forward(request,response);
    }
    //根据ID查找book  可以对数据进行修改操作
    protected void getBook(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String id = request.getParameter("id");
        Books book = bookDao.queryBookById(Integer.parseInt(id));
        request.setAttribute("book",book);
        request.getRequestDispatcher("jspdemo/bookEdit.jsp").forward(request,response);
    }
    //分页处理
    //一个page 是进入到后台管理的图书分页 另一个是进入到主页面购物车
    // 两个实现方式相同  跳转路径不同
    protected void page(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    //获取参数  pageno pagesize
        String pageNo = request.getParameter("pageNo");
        int pageNo1=0;
        if(pageNo!=null){
            pageNo1 = Integer.parseInt(pageNo);
        }
        else {
            pageNo1=1;
        }
        String pageSize = request.getParameter("pageSize");
        int pageSize1=0;
        if(pageSize==null){
            pageSize1=Page.Page_Size;
        }
        else {
            pageSize1=Integer.parseInt(pageSize);
        }
        //调用bookdao.page  保存page对象到request  已知当前页和每页数量 获取到当前page的所有信息
        Page<Books> page=page1(pageNo1,pageSize1);
        // 请求转发到显示页面
        request.setAttribute("page",page);
        request.getRequestDispatcher("jspdemo/bookManage.jsp").forward(request,response);
    }

    //补充page属性的信息
    public Page<Books> page1(int pageNo, int PageSize) {
        Page<Books> page=new Page<>();
        //赋值
        page.setPageNo(pageNo);
        page.setPageSize(PageSize);
        //总记录数  访问数据库 记录总共商品数量
        Integer pageTotalCount=bookDao.queryForPageTotalCount();
        page.setPageTotalCount(pageTotalCount);
        //总页码
        Integer pageTotal=pageTotalCount/PageSize;
        if(pageTotalCount%PageSize>0){
            pageTotal++;
        }
        page.setPageTotal(pageTotal);
        //求当前的信息  当前页面的第一个数据的号
        //eg:一个页面显示四条数据  如果是第一个页面的话 显示的信息为0-3 共四条数据 后面类似
        int begin=(pageNo-1)*PageSize;
       //访问数据库
        List<Books> items=bookDao.queryForPageItems(begin,PageSize);
       //求当前页数据
        page.setItem(items);
        return page;
    }
    //分页处理   进入初始页面
    protected void firstPage(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //获取参数  pageno pagesize
        String pageNo = request.getParameter("pageNo");
        int pageNo1=0;
        if(pageNo!=null){
            pageNo1 = Integer.parseInt(pageNo);
        }
        else {
            pageNo1=1;
        }
        String pageSize = request.getParameter("pageSize");
        int pageSize1=0;
        if(pageSize==null){
            pageSize1=Page.Page_Size;
        }
        else {
            pageSize1=Integer.parseInt(pageSize);
        }
        //调用bookdao.page  保存page对象到request
        Page<Books> page=page1(pageNo1,pageSize1);
        // 请求转发到显示页面
        request.setAttribute("page",page);
        request.getRequestDispatcher("index1.jsp").forward(request,response);
    }
}

主页面展示页面

index1.jsp:

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>书城购物系统</title>
</head>
<body>
<h1 align=center><font color="#8a2be2" > 欢迎来到书城购物系统，祝您生活愉快</font></h1><hr>
<h4 align=right><a href="/BookServlet?action=page">图书管理</a>&nbsp;&nbsp;&nbsp;<a href="jspdemo/cart.jsp">我的购物车</a> </h4>
<hr>
<style>
    li {float:left;list-style:none;}
</style>
<script type="text/javascript">
    function show() {
        alert("-_- 添加成功 -_-");
        shopping.submit();
    }
</script>
<c:forEach items="${requestScope.page.item}" var="book">
<ul>
    <li>
        <form name="shopping" action="/AddCartServlet" method="post">
        <img  src="${book.imgPath}"/><br>
        书名:${book.name}<br>作者:${book.author}<br>
        价格:${book.price}<br>销量:${book.sales}<br>库存:${book.stock}<br>
         <input type="hidden" name="id" value="${book.id}"><br>
            选择数量: <input type="text" name="count" size="3">
        <input type="submit" value="加入购物车" onclick="show()">
       </form>
    </li>
</ul>
</c:forEach>
<br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br>
<%--添加分页条--%>
<div id="page_nav">
    <c:if test="${requestScope.page.pageNo>1}">
        <a href="/BookServlet?action=firstPage&pageNo=1">首页</a>
        <a href="/BookServlet?action=firstPage&pageNo=${requestScope.page.pageNo-1}">上一页</a>
    </c:if>
    <c:forEach begin="1" end="${requestScope.page.pageTotal}" var="i">
        <a href="/BookServlet?action=firstPage&pageNo=${i}">${i}</a>
    </c:forEach>
    <c:if test="${requestScope.page.pageNo < requestScope.page.pageTotal}">
        <a href="/BookServlet?action=firstPage&pageNo=${requestScope.page.pageNo+1}">下一页</a>
        <a href="/BookServlet?action=firstPage&pageNo=${requestScope.page.pageTotal}">末页</a>
    </c:if>
    <form action="/BookSearchServlet1">
        共${requestScope.page.pageTotal}页, ${requestScope.page.pageTotalCount}条记录
        跳转到<input value="4" type="text" name="p" >页
        <input type="hidden" name="pageTotal"value="${requestScope.page.pageTotal}">
        <input  type="submit" value="确定">
    </form>
</div>
</body>
</html>

文本框输入页面数跳转到某个页面：
BookSearchServlet1.java

package servlet;

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;

@WebServlet("/BookSearchServlet1")
public class BookSearchServlet1 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request,response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String p = request.getParameter("p");
        int page = Integer.parseInt(p);
        String pageTotal = request.getParameter("pageTotal");
        int total = Integer.parseInt(pageTotal);
        if (page <= 1) {
            response.sendRedirect(request.getContextPath() + "/BookServlet?action=firstPage&pageNo=1");
        } else if (page >= total) {
            response.sendRedirect(request.getContextPath() + "/BookServlet?action=firstPage&pageNo=" + total);
        } else {
            response.sendRedirect(request.getContextPath() + "/BookServlet?action=firstPage&pageNo=" + p);
        }
    }
}

加入购物车后点击我的购物车便可查看加入购物车的信息，同时可对购物车里面的数量进行修改：

cart.jsp购物车信息展示

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>我的购物车</title>
</head>
<body>
<c:if test="${empty sessionScope.cart.items}">
    亲亲，你的购物车目前是空的呢 <a href="http://localhost:8080/BookServlet?action=firstPage">点击此处返回购物页面</a>
</c:if>
<%--如果购物车不是空的则会显示以下内容--%>
<c:if test="${not empty sessionScope.cart.items}">
<table>
<tr>
    <td>商品名称</td>
    <td>数量</td>
    <td>单价</td>
    <td>金额</td>
    <td colspan="2">操作</td>
</tr>

<c:forEach items="${sessionScope.cart.items}" var="entry">
    <form action="/UpdateCartServlet">
    <tr>
    <td>${entry.value.name}&nbsp;&nbsp;</td>
    <td><input type="text"  style="width: 80px;" name="count" value="${entry.value.count}"></td>
    <td>${entry.value.price}&nbsp;&nbsp;</td>
    <td>${entry.value.totalPrice}&nbsp;&nbsp;</td>
        <!--隐秘传入ID  为更新操作服务 -->
        <input type="hidden" name="id" value="${entry.value.id}">
        <td><input type="submit" value="修改"></td>
        <td><a href="/CartServlet?action=delete&id=${entry.value.id}">删除</a></td>
    </tr>
    </form>
    </c:forEach>
</table>
    购物车中共有 ${sessionScope.cart.totalCount}件商品&nbsp;&nbsp;总金额为${sessionScope.cart.totalPrice}元
<a href="/CartServlet?action=clear">清空购物车</a>&nbsp;&nbsp;
<a href="http://localhost:8080/BookServlet?action=firstPage">返回购物页面</a>&nbsp;&nbsp; 去结账
    </c:if>
</body>
</html>

在这里可以直接在文本框中对数量进行修改，点击修改便完成。
修改处理对应的代码：
UpdateCartServlet.java

package servlet;
import bean.Books;
import bean.Cart;
import bean.CartItem;
import dao.impl.BookDaoImpl;
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;
@WebServlet("/UpdateCartServlet")
public class UpdateCartServlet extends HttpServlet {
    BookDaoImpl bookDao=new BookDaoImpl();
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request,response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        update(request,response);
    }
    //修改购物车数量
    protected void update(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
        String id1=request.getParameter("id");
        String count1=request.getParameter("count");
        int id=0,count=0;
        if(id1!=null){
            id=Integer.parseInt(id1);
        }
        if(count1!=null){
            count=Integer.parseInt(count1);
        }
        Cart cart = (Cart)request.getSession().getAttribute("cart");
        if(cart!=null){
            cart.updateCount(id,count);
        }
        //返回上个页面
        response.sendRedirect(request.getHeader("Referer"));
    }
}

对购物车的商品信息进行删除或者进行清空购物车,修改数量的操作时，调用CartServlet.java的代码

package servlet;
import bean.Books;
import bean.Cart;
import bean.CartItem;
import dao.impl.BookDaoImpl;

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.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
@WebServlet("/CartServlet")
public class CartServlet extends HttpServlet {
    BookDaoImpl bookDao=new BookDaoImpl();
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //中文乱码解决方法
        response.setContentType("text/html;charset=utf-8");
        request.setCharacterEncoding("utf-8");
        String action=request.getParameter("action");
        try {
            Method method = this.getClass().getDeclaredMethod(action, HttpServletRequest.class, HttpServletResponse.class);
            method.invoke(this,request,response);
        }
        catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
    }
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      doPost(request,response);
    }
   //删除信息
    protected void delete(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
       String id1=request.getParameter("id");
       int id=0;
       if(id1!=null){
           id=Integer.parseInt(id1);
       }
       Cart cart=(Cart)request.getSession().getAttribute("cart");
       if(cart!=null){
           cart.deleteItem(id);
           response.sendRedirect(request.getHeader("Referer"));
       }
   }
   //清空购物车
   protected void clear(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
       Cart cart = (Cart)request.getSession().getAttribute("cart");
       cart.clear();
       response.sendRedirect(request.getHeader("Referer"));
    }
    //修改购物车数量
    protected void update(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
        String id1=request.getParameter("id");
        String count1=request.getParameter("count");
        System.out.println(count1);
        int id=0,count=0;
        if(id1!=null){
            id=Integer.parseInt(id1);
        }
        if(count1!=null){
            count=Integer.parseInt(count1);
        }
        Cart cart = (Cart)request.getSession().getAttribute("cart");
        if(cart!=null){
            cart.updateCount(id,count);
        }
        response.sendRedirect(request.getHeader("Referer"));
    }
}

图书后台信息管理

点击图书管理，程序会跳转到BookServlet调用其page方法，经过处理后跳转到bookManage.jsp界面，显示所有图书信息。

<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2020/11/24
  Time: 21:43
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>图书管理</title>
</head>
<body>
<table>
    <tr>
        <td>名称</td>
        <td>作者</td>
        <td>价格</td>
        <td>销量</td>
        <td>库存</td>
        <td colspan="2">操作</td>
    </tr>
    <!--获取由bookservlet.page()传的值-->
    <c:forEach items="${requestScope.page.item}" var="book">
    <tr>
        <td>${book.name}</td>
        <td>${book.author}</td>
        <td>${book.price}</td>
        <td>${book.sales}</td>
        <td>${book.stock}</td>
        <td><a href="/BookServlet?action=getBook&id=${book.id}">操作</a></td>
        <td><a href="/BookServlet?action=delete&id=${book.id}">删除</a> </td>
    </tr>
    </c:forEach>
    <tr>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td><a href="jspdemo/bookEdit.jsp">添加图书</a></td>
    </tr>
</table>
<div id="page_nav">
    <c:if test="${requestScope.page.pageNo>1}">
        <a href="/BookServlet?action=page&pageNo=1">首页</a>
        <a href="/BookServlet?action=page&pageNo=${requestScope.page.pageNo-1}">上一页</a>
    </c:if>
    <c:forEach begin="1" end="${requestScope.page.pageTotal}" var="i">
        <a href="/BookServlet?action=page&pageNo=${i}">${i}</a>
    </c:forEach>
<c:if test="${requestScope.page.pageNo < requestScope.page.pageTotal}">
    <a href="/BookServlet?action=page&pageNo=${requestScope.page.pageNo+1}">下一页</a>
    <a href="/BookServlet?action=page&pageNo=${requestScope.page.pageTotal}">末页</a>
</c:if>
    <form action="/BookSearchServlet">
    共${requestScope.page.pageTotal}页, ${requestScope.page.pageTotalCount}条记录
       跳转到<input value="4" type="text" name="p" >页
        <input type="hidden" name="pageTotal"value="${requestScope.page.pageTotal}">
        <input  type="submit" value="确定">
   </form>
    <a href="http://localhost:8080/BookServlet?action=firstPage">返回购物页面</a>
</div>
</body>
</html>

对后台信息可以进行添加删除修改，一般是管理员身份的可以对此进行操作。进行操作选项调用BookServlet的getBook方法，删除操作调用BookServlet的delete方法，添加调用bookEdit.jsp

bookEdit.jsp对后台图书进行添加操作

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2020/11/24
  Time: 22:04
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>信息编辑</title>
</head>
<body>
<!--如果路径后面没有ID则为添加商品信息，如果有ID则为修改商品信息-->
<form action="/BookServlet" method="post">
    <input type="hidden" name="action" value="${empty param.id? "add":"update"}">
    <%
    session.setAttribute("id", request.getParameter("id"));
    %>
    <table>
        <tr>
            <td>名称</td>
            <td>作者</td>
            <td>价格</td>
            <td>销量</td>
            <td>库存</td>
            <td colspan="2">操作</td>
        </tr>
        <tr>
            <td><input name="name" type="text" value="${requestScope.book.name}"></td>
            <td><input name="author" type="text" value="${requestScope.book.author}"></td>
            <td><input name="price" type="text" value="${requestScope.book.price}"></td>
            <td><input name="sales" type="text" value="${requestScope.book.sales}"></td>
            <td><input name="stock" type="text" value="${requestScope.book.stock}"></td>
            <td><input type="submit" value="添加"></td>
        </tr>
    </table>
</form>
</body>
</html>

该项目代码稍微长，但其思想原理却不是很复杂。主要是对数据库的基本操作和jsp的基本用法。
代码有难点的地方我都标了注释，仍有问题的欢迎打扰。

本文地址：https://blog.csdn.net/qq_43505820/article/details/110825677

《史上功能最全Web购物车实现（基于jsp+java+servlet+dao）包括后台图书管理、实现数据库分页等功能.doc》

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