模拟亚马逊、淘宝等浏览记录功能（访问数据库）

Q题目

现在要求，模拟一个类似的功能，实体为一个网上书店，要求显示最近的三条浏览记录，使用数据库存储数据和查询数据，如下图

例如：
1）现有如下网上书店：

本站书籍目录：    JAVA    C++    C语言    Linux    Android最近三次浏览记录：

3）浏览第一个商品后，若为Java，显示界面

本站书籍目录：    JAVA    C++    C语言    Linux    Android最近三次浏览记录：    JAVA

4）浏览第二个商品，若为C++

5）浏览第三个商品，若为Java，此时涉及一个排序问题了，最前的必须是最近浏览的。

6）浏览第四个商品，为C语言

具体分析见：http://blog.csdn.net/baidu_37107022/article/details/72783206

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实现代码

目录

注意：数据库驱动jar包，以及配置文件info.properties

数据库数据如下：

book类

package com.tcb.domain;public class Book {    private int id;    private String name;    private int price;    private String author;    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public int getPrice() {        return price;    }    public void setPrice(int price) {        this.price = price;    }    public String getAuthor() {        return author;    }    public void setAuthor(String author) {        this.author = author;    }    public Book(String name, int price, String author) {        super();        this.name = name;        this.price = price;        this.author = author;    }    @Override    public String toString() {        return "Book [id=" + id + ", name=" + name + ", price=" + price + ", author=" + author + "]";    }    public Book() {        super();        // TODO Auto-generated constructor stub    }}

bookDao类：查询数据库内容

package com.tcb.dao;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.util.ArrayList;import com.tcb.domain.Book;import com.tcb.utils.DBUtils;public class BookDao {    //查询指定书籍的详情    public Book queryBook(int id){        Connection connection=DBUtils.getConnection();        try {            String sql="select * from book where id=?";            PreparedStatement ps=connection.prepareStatement(sql);            ps.setInt(1, id);            ResultSet resultSet=ps.executeQuery();            while(resultSet.next()){                int id2= resultSet.getInt("id");                String name=resultSet.getString("name");                int price=resultSet.getInt("price");                String author=resultSet.getString("author");                Book book=new Book(name, price, author);                book.setId(id2);                return book;            }        } catch (SQLException e) {            e.printStackTrace();        }        return null;    }    //查询出所有书籍信息用于展示    public ArrayList<Book> queryAllBook(){        Connection connection=DBUtils.getConnection();        ArrayList<Book> list=new ArrayList<>();        try {            String sql="select * from book";            PreparedStatement ps=connection.prepareStatement(sql);            ResultSet resultSet=ps.executeQuery();            while(resultSet.next()){                int id=resultSet.getInt("id");                String name=resultSet.getString("name");                int price=resultSet.getInt("price");                String author=resultSet.getString("author");                Book book=new Book(name, price, author);                book.setId(id);                list.add(book);            }        } catch (SQLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        return list;    }}

工具类：获得数据库连接Connection

package com.tcb.utils;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import java.util.ResourceBundle;public class DBUtils {    public static String driverName="";    public static String url="";    public static String username="";    public static String password="";    static{        ResourceBundle resourceBundle=ResourceBundle.getBundle("info");        driverName=resourceBundle.getString("driverName");        url=resourceBundle.getString("url");        username=resourceBundle.getString("username");        password=resourceBundle.getString("password");    }    public static Connection getConnection(){        try {            //1.注册驱动            Class.forName(driverName);            //2.获取连接            Connection connection = DriverManager.getConnection(url,username,password);            return connection;        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        return null;    }    public  static void closeAll(ResultSet resultSet,Statement statement ,Connection  connection){        if (resultSet!=null) {            try {                resultSet.close();            } catch (SQLException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }        if (statement!=null) {            try {                statement.close();            } catch (SQLException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }        if (connection!=null) {            try {                connection.close();            } catch (SQLException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }    }}

配置文件info.properties
url的最后一个参数：book为数据库名称（自己定）
数据库的用户名username和密码password（根据自己设置的填写）

driverName=com.mysql.jdbc.Driverurl=jdbc\:mysql\://localhost\:3306/bookusername=rootpassword=123

展示所有书籍BookContent

package com.tcb.web.servlet;import java.io.IOException;import java.io.PrintWriter;import java.util.ArrayList;import java.util.Arrays;import java.util.HashMap;import javax.servlet.ServletException;import javax.servlet.http.Cookie;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.tcb.dao.BookDao;import com.tcb.domain.Book;import com.tcb.utils.DBUtils;public class ShowBookContent extends HttpServlet {    private static final long serialVersionUID = 1L;    public ShowBookContent() {        super();        // TODO Auto-generated constructor stub    }    protected void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        request.setCharacterEncoding("utf-8");        response.setContentType("text/html;charset=utf-8");        PrintWriter writer = response.getWriter();        // 展示所有书籍        writer.write("本站书籍目录：<br>");        BookDao bookDao=new BookDao();        ArrayList<Book> list=bookDao.queryAllBook();        for (Book book : list) {            writer.write("<a href='" + request.getContextPath() + "/ShowBookDetails?id=" + book.getId()+ "'>"                    + book.getName() + "</a><br>");        }        // 显示最近三次的访问记录        writer.write("最近三次浏览记录：<br>");        Cookie[] cookies = request.getCookies();        if (cookies != null) {            for (Cookie cookie : cookies) {                String name = cookie.getName();                if ("ids".equals(name)) {                    String value = cookie.getValue();                    String[] values = value.split("-");                    for (int i = 0; i < values.length; i++) {                        String id = values[i];                        Book book1 = bookDao.queryBook(Integer.parseInt(id));                        writer.write("<a  href='ShowBookDetails?id="+book1.getId() + "'>" + book1.getName()                                + "</a><br>");                    }                }            }        }    }    protected void doPost(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        // TODO Auto-generated method stub        doGet(request, response);    }}

展示书籍具体信息

package com.tcb.web.servlet;import java.io.IOException;import java.io.PrintWriter;import java.util.Arrays;import java.util.LinkedList;import java.util.List;import javax.servlet.ServletException;import javax.servlet.http.Cookie;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.tcb.dao.BookDao;import com.tcb.domain.Book;import com.tcb.utils.DBUtils;public class ShowBookDetails extends HttpServlet {    private static final long serialVersionUID = 1L;    public ShowBookDetails() {        super();        // TODO Auto-generated constructor stub    }    protected void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        request.setCharacterEncoding("utf-8");        response.setContentType("text/html;charset=utf-8");        PrintWriter writer = response.getWriter();        // 显示被查看书籍的具体信息        BookDao bookDao=new BookDao();        String id = request.getParameter("id");        Book book = bookDao.queryBook(Integer.parseInt(id));        writer.write("您查看了" + book.getName() + "这本书。<br><br>");        writer.write("书籍具体信息如下：<br>");        writer.write(book.getName() + "<br>");        writer.write(book.getAuthor() + "<br>");        writer.write(book.getPrice() + "<br>");        // 存储该次访问记录,方便在主页面中显示最近的访问记录        // 存取数据格式为：3-2-1 先要进行数据拆分，根据情况做修改数据操作，再将数据合并放回到cookie中        Cookie[] cookies = request.getCookies();        if (cookies != null) {            //创建一个Stringbuffer来存取所有Cookie的名字，用于判断Cookies数组中是否有ids这个Cookie，没有就需要创建            StringBuffer cookieNames=new StringBuffer();            //遍历Cookies数组            for (Cookie cookie : cookies) {                //得到Cookie名字                String name = cookie.getName();                //将Cookie名字存起来                cookieNames.append(name+"-");  //加“-”目的是：防止分隔开每个Cookie的名字，防止相连的名字组合匹配到ids                //若有ids这个Cookie，就需要做处理                if ("ids".equals(name)) {                    // 取出Cookie中存的值                    String value = cookie.getValue();                    // ids这个Cookie取出的值为空那就没必要做拆分了                    if (value != null && !"".equals(value)) {                        String[] values = value.split("-");                        // 数组转化成Collection集合                        List<String> list = Arrays.asList(values);                        // 把list集合直接转化成LinkedList，为了方便后续处理                        LinkedList<String> linked = new LinkedList<String>(list);                        // 判断Cookie值中包含id否                        if (linked.contains(id)) {                            linked.remove(id);                        } else {                            if (linked.size() > 2) {                                linked.removeLast();                            }                        }                        linked.addFirst(id);                        // 将存进linkedList中的数据取出来组合成1-2或1-2-3等形式，放到Cookie中                        String result = "";                        for (int i = 0; i < linked.size(); i++) {                            result += linked.get(i);                            if (i < linked.size()-1) {                                result += "-";                            }                        }                        Cookie cookie2 = new Cookie("ids", result);                        cookie2.setMaxAge(10 * 60);                        response.addCookie(cookie2);                    }                }            }            if(!cookieNames.toString().contains("ids")){                Cookie cookie = new Cookie("ids", id);                cookie.setMaxAge(10 * 60);                response.addCookie(cookie);            }        } else {            Cookie cookie = new Cookie("ids", id);            cookie.setMaxAge(10 * 60);            response.addCookie(cookie);        }    }    protected void doPost(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        // TODO Auto-generated method stub        doGet(request, response);    }}

不使用，而使用集合实现数据存储实现该功能：http://blog.csdn.net/baidu_37107022/article/details/72783206