Cookie 简单使用记录浏览记录

ItemsDAO.java

package dao;
import java.util.* ;
import java.sql.* ;

import util.DBHelper;

import entity.Items;
//商品的业务逻辑类
public class ItemsDAO {
    static public   ArrayList<Items> getAllItems()
    {
        Connection conn = null ;
        PreparedStatement stmt = null ;
        ResultSet rs = null ;    //数据集
        ArrayList<Items> list = new ArrayList<>() ;
        try {
            conn = DBHelper.getConnection();
            String sql = "select * from items;" ;
            stmt = conn.prepareStatement(sql);
            rs = stmt.executeQuery();
            while(rs.next()){
                Items item = new Items() ;
                item.setId(rs.getInt("id"));
                item.setName(rs.getString("name"));
                item.setCity(rs.getString("city"));
                item.setPricce(rs.getInt("pricce"));
                item.setPicture(rs.getString("picture"));
                
                list.add(item);
            }
            return list ;
            
        } catch (Exception e){
            e.printStackTrace() ;
            return null ;
        } 
        
        finally{
            //释放数据集对象
            if(rs != null)
            {
                try{
                    rs.close() ;
                    rs = null ;
                } catch (Exception ex){
                    ex.printStackTrace() ;
                }
            }
            //释放语句对象
            
            if(stmt != null)
            {
                try{
                    stmt.close() ;
                    stmt = null ;
                } catch (Exception ex){
                    ex.printStackTrace() ;
                }
            }
            
        }
        
        
    }
    
    
    //根据商品编号获得商品资料
    public Items getItemsById(int id){
        Connection conn = null ;
        PreparedStatement stmt = null ;
        ResultSet rs = null ;    //数据集
        try {
            conn = DBHelper.getConnection();
            String sql = "select * from items where id = ?;" ;
            stmt = conn.prepareStatement(sql);
            stmt.setInt(1,id);
            rs = stmt.executeQuery();
            if(rs.next()){
                Items item = new Items() ;
                item.setId(rs.getInt("id"));
                item.setName(rs.getString("name"));
                item.setCity(rs.getString("city"));
                item.setPricce(rs.getInt("pricce"));
                item.setPicture(rs.getString("picture"));
                
                return item;
            }
            else
                return null ;
            
        } catch (Exception e){
            e.printStackTrace() ;
            return null ;
        } 
        
        finally{
            //释放数据集对象
            if(rs != null)
            {
                try{
                    rs.close() ;
                    rs = null ;
                } catch (Exception ex){
                    ex.printStackTrace() ;
                }
            }
            //释放语句对象
            
            if(stmt != null)
            {
                try{
                    stmt.close() ;
                    stmt = null ;
                } catch (Exception ex){
                    ex.printStackTrace() ;
                }
            }
    }
    
    }
    //获取最近浏览的前五条
    public ArrayList<Items> getViewList(String list){
        ArrayList<Items> itemlist = new ArrayList<Items> () ;
        int iCount = 5 ;
        if(list != null && list.length()>0){
            String [] arr = list.split(",");
            
            if(arr.length >= 5){            
                for(int i = arr.length-1 ; i >= arr.length-iCount-1 ; i--){
                     itemlist.add(getItemsById(Integer.parseInt(arr[i])));
                }
            } else {
                for(int i = arr.length-1 ; i>=0 ; i --){
                     itemlist.add(getItemsById(Integer.parseInt(arr[i])));
                }
            }
            
            return itemlist ;
        } else {
            return null ;
        }
    }
}

Items.java

package entity;

public class Items {
    private int id;
    private String name;
    private String city;
    private int pricce;
    private String picture;

    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 String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public int getPricce() {
        return pricce;
    }

    public void setPricce(int pricce) {
        this.pricce = pricce;
    }

    public String getPicture() {
        return picture;
    }

    public void setPicture(String picture) {
        this.picture = picture;
    }

}

DBHElper.java

package util;
import java.sql.Connection;
import java.sql.DriverManager;


public class DBHelper {
    
    private static final String driver = "com.mysql.jdbc.Diver";
    private static final String url = "jdbc:mysql://localhost:3306/zhuopengDB?useUnicode=true&characterEncoding=GB2312"; 
    private static final String username = "zhuopeng" ;
    private static final String password = "zhuopeng" ;
    private static Connection conn = null ;
    //静态代码块加载驱动
    static 
    {
        try
        {
            Class.forName("com.mysql.jdbc.Driver"); 
        } catch (Exception e)
        {
            e.printStackTrace();
            System.out.println("驱动");
        }
        
    }
    //单例模式 
    public static Connection getConnection() throws Exception
    {
        if(conn == null)
        {
            conn = DriverManager.getConnection(url,username,password);
        }
        return conn ;
    }
    
}

index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ page import = "dao.ItemsDAO"  %>
<%@ page import = "java.util.*" %>
<%@ page import = "entity.Items"   %>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>商品</title>
</head>
<body>
    <h1>商品展示</h1>
    <hr> 
    <center>
        <table width="550" height = "60 "cellpadding = "0" celpacing = "0" border = "0">
        <tr>
            <td>
                <%
                    ItemsDAO  itemsDao = new  ItemsDAO() ;
                    ArrayList<Items> list = itemsDao.getAllItems() ;
                    if(list != null && list.size() > 0 ){
                        for(int i = 0 ; i < list.size() ; i ++){
                        Items item = list.get(i);
    
                %>
                <!--  循环部分 -->
                <div>                                
                    <dl>                    
                        <dt>
                            <a href = "details.jsp?id=<%=item.getId()%>"> <img src ="E:javawebTestMyfirstWebappWebContentWEB-INFimages<%=item.getPicture() %>"   width = "100" heigh="100"/></a>
                        </dt>
                        <dd class = "dd_name" > <%=item.getName() %> </dd>
                        <dd class = "dd_city" > <%=item.getCity() %>  &nbsp; &nbsp; 价格:<%=item.getPricce() %></dd>
                
                    </dl>                    
                </div>
                <!-- 循环结束哦 -->
                <%
                        }
                        
                    }        
                %>
            </td>
        </tr>        
        </table>    
    </center>    
</body>
</html>

details.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ page import = "dao.ItemsDAO"  %>
<%@ page import = "java.util.*" %>
<%@ page import = "entity.Items"   %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
    <%
        ItemsDAO itemDao = new ItemsDAO () ;
        Items item = itemDao.getItemsById(Integer.parseInt(request.getParameter("id")));
        if(item != null)
        {
    %>
        <img src ="E:javawebTestMyfirstWebappWebContentWEB-INFimages<%=item.getPicture() %>"  width = "400" heigh="400"/><br>
        产地:<%=item.getCity() %><br>
        价格:<%=item.getPricce() %><br>
        
    <%
        }
    %>
    
    <%
        String list = "" ;
        Cookie [] cookies = request.getCookies() ;
        if(cookies !=null && cookies.length>0)
        for(Cookie c :cookies){
            if(c.getName() . equals("ListViewCookie"))
            {
                list = c.getValue() ;
            }
        }
        
        list += request.getParameter("id")+"," ;
        String [] arr = list.split(",");
        if(arr!=null && arr.length>0 ){
            if(arr.length>=100)
            {
                list = "" ;
            }
        }
        Cookie cookie = new Cookie("ListViewCookie" ,list) ;    //创建Cookie
        cookie.setMaxAge(8000);
        response.addCookie(cookie);                                //添加Cookie
    %>
    <hr>
    浏览过的商品：<br>
    <%
        ArrayList<Items> itemslist = itemDao.getViewList(list);
        if(itemslist!= null && itemslist.size()>0){
            for(Items i : itemslist){
        
    %>
        <img src ="E:javawebTestMyfirstWebappWebContentWEB-INFimages<%=i.getPicture() %>"  width = "200" heigh="200"/><br>
        产地:<%=i.getCity() %><br>
        价格:<%=i.getPricce() %><br>
    <%
            }
        }
    %>
</body>
</html>