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

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;
}
pub
14ce6
lic 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.Driver
url=jdbc\:mysql\://localhost\:3306/book
username=root
password=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