JAVAEE model1模型實(shí)現(xiàn)商品瀏覽記錄（去除重復(fù)的瀏覽記錄）（一）

更新時(shí)間：2016年11月16日 11:23:22 作者：scx_white

這篇文章主要為大家詳細(xì)介紹了JAVAEE model1模型實(shí)現(xiàn)商品瀏覽記錄，去除重復(fù)的瀏覽記錄,具有一定的參考價(jià)值，感興趣的小伙伴們可以參考一下

在javaee中Model1模型是以jsp頁(yè)面為中心的，jsp既要對(duì)瀏覽器的request做出邏輯處理（使用javabean），訪問(wèn)數(shù)據(jù)庫(kù)也要顯示出相關(guān)的頁(yè)面。
在model1模型中，沒(méi)有servlet。
Model1結(jié)果圖如下：

Model1的可維護(hù)性可擴(kuò)展性都是較差的只適合小項(xiàng)目。

首先運(yùn)行結(jié)果

goods.jsp

<%@page import="entity.Items"%> 
<%@page import="dao.ItemsDao"%> 
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> 
<% 
  String path = request.getContextPath(); 
  String basePath = request.getScheme() + "://" 
      + request.getServerName() + ":" + request.getServerPort() 
      + path + "/"; 
%> 
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 
<html> 
<head> 
<base href="<%=basePath%>"> 
 
<title>My JSP 'index.jsp' starting page</title> 
<meta http-equiv="pragma" content="no-cache"> 
<meta http-equiv="cache-control" content="no-cache"> 
<meta http-equiv="expires" content="0"> 
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> 
<meta http-equiv="description" content="This is my page"> 
<!-- 
  <link rel="stylesheet" type="text/css" href="styles.css"> 
  --> 
<style type="text/css"> 
div { 
  float: left; 
  margin: 10px; 
} 
 
div dd { 
  margin: 0px; 
  font-size: 10pt; 
} 
 
div dd.dd_name { 
  color: blue; 
} 
 
div dd.dd_city { 
  color: #000; 
} 
</style> 
</head> 
 
<body> 
  <center> 
    <h1>商品展示</h1> 
    <hr> 
    <table width="800" height="60" cellpadding="0" cellspacing="0" 
      border="0"> 
      <tr> 
        <td> 
          <% 
            ItemsDao dao = new ItemsDao(); 
            ArrayList<Items> list = new ArrayList<Items>(); 
            //從dao中獲取所有的商品 并保存到list集合中 
            list = dao.getAllItems(); 
            if (list != null && list.size() > 0) { 
              //循環(huán)遍歷集合 并顯示 
              for (int i = 0; i < list.size(); i++) { 
                Items item = list.get(i); 
          %> 
          <div> 
            <dl> 
              <dt> 
                <a href="details.jsp?id=<%=item.getId()%>"><img 
                  src="images/<%=item.getPicture()%>" width="120" height="90" 
                  border="1" /> 
                </a> 
              </dt> 
              <dd class="dd_name"><%=item.getName()%></dd> 
              <dd class="dd_city"> 
                產(chǎn)地:<%=item.getCity()%> 價(jià)格:￥ 
                <%=item.getPrice()%></dd> 
            </dl> 
          </div> <% 
  } 
  } 
 %> 
        </td> 
 
      </tr> 
    </table> 
  </center> 
</body> 
</html>

在代碼中表示商品的圖片

<span style="white-space:pre">               </span>

<a href="details.jsp?id=<%=item.getId()%>">

<img src="images/<%=item.getPicture()%>" width="120" height="90"  border="1" /> 
 
</a>

通過(guò)點(diǎn)擊商品的圖片把當(dāng)前商品的id傳值給details頁(yè)面
details.jsp通過(guò)商品的id來(lái)顯示詳細(xì)商品，而瀏覽記錄由cookies維護(hù)

<%@page import="org.apache.taglibs.standard.tag.common.xml.ForEachTag"%> 
<%@page import="entity.Items"%> 
<%@page import="dao.ItemsDao"%> 
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> 
<% 
  String path = request.getContextPath(); 
  String basePath = request.getScheme() + "://" 
      + request.getServerName() + ":" + request.getServerPort() 
      + path + "/"; 
%> 
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 
<html> 
<head> 
<base href="<%=basePath%>"> 
 
<title>My JSP 'index.jsp' starting page</title> 
<meta http-equiv="pragma" content="no-cache"> 
<meta http-equiv="cache-control" content="no-cache"> 
<meta http-equiv="expires" content="0"> 
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> 
<meta http-equiv="description" content="This is my page"> 
<style type="text/css"> 
#historyview { 
  border: 1; 
  background: #EAEAEE; 
} 
 
#historyview td { 
  font-size: 10px; 
} 
</style> 
</head> 
 
<body> 
  <center> 
    <h1>商品詳情</h1> 
    <hr> 
    <table width="750" border="0" cellpadding="0" cellspacing="0"> 
      <tr> 
        <td width="70%"> 
          <center> 
            <table border="0"> 
              <% 
                ItemsDao dao = new ItemsDao(); 
                //根據(jù)request傳來(lái)的商品id 向dao中獲得相對(duì)應(yīng)的商品對(duì)象 
                Items item = dao.getItemById(Integer.parseInt(request 
                    .getParameter("id"))); 
                if (item != null) { 
              %> 
              <tr> 
                <td rowspan="5"><img src="images/<%=item.getPicture()%>" 
                  width="200" height="150"></td> 
              </tr> 
              <tr> 
                <td><b><%=item.getName()%></b> 
                </td> 
              </tr> 
              <tr> 
                <td id="cityname">產(chǎn)地：<%=item.getCity()%></td> 
              </tr> 
              <tr> 
                <td id="pricename">價(jià)格：<%=item.getPrice()%> ￥</td> 
              </tr> 
              <tr> 
                <td id="pricename">價(jià)格：<%=item.getPrice()%> ￥</td> 
              </tr> 
              <% 
                } 
                //將該商品加入cookies 
                Cookie[] cookies = request.getCookies(); 
                String historyStr = ""; 
                for (Cookie c : cookies) { 
                  if (c.getName().equals("history")) { 
                    historyStr = c.getValue(); 
                  } 
                } 
                historyStr += item.getId() + ","; 
                Cookie c = new Cookie("history", historyStr); 
                //重新設(shè)置cookies 
                response.addCookie(c); 
              %> 
            </table> 
          </center></td> 
 
        <td width="30%" valign="top" id="historyview"> 
          <center> 
            <table> 
              <tr> 
                <td><b>你瀏覽過(guò)的商品</b></td> 
              </tr> 
              <% 
                //根據(jù)cookie 從dao獲取最后瀏覽的三次記錄 并保存到list集合 
                ArrayList<Items> historyItems = dao.getHistoryView(historyStr); 
                if (historyItems != null && historyItems.size() > 0) { 
                  //遍歷集合 
                  for (Items historyItem : historyItems) { 
              %> 
              <tr> 
                <td><a href="details.jsp?id=<%=historyItem.getId()%>"><img 
                    src="images/<%=historyItem.getPicture()%>" width="100" 
                    height="80" border="1"> </a></td> 
              </tr> 
              <tr> 
                <td><b><%=historyItem.getName()%></b> 
                </td> 
              </tr> 
              <tr> 
                <td>產(chǎn)地：<%=historyItem.getCity()%></td> 
              </tr> 
              <% 
                } 
                } 
              %> 
            </table> 
          </center> 
        </td> 
      </tr> 
    </table> 
 
  </center> 
</body> 
</html>

dao層 負(fù)責(zé)商品在數(shù)據(jù)庫(kù)中的查詢操作

package dao; 
 
import java.sql.Connection; 
import java.sql.PreparedStatement; 
import java.sql.ResultSet; 
import java.sql.SQLException; 
import java.util.ArrayList; 
import util.DBHelper; 
import entity.Items; 
 
//商品的業(yè)務(wù)邏輯類 
public class ItemsDao { 
  // 獲得所有商品信息 
  public ArrayList<Items> getAllItems() { 
    // 商品集合 
    ArrayList<Items> list = new ArrayList<Items>(); 
    Connection conn = null; 
    PreparedStatement ps = null; 
    ResultSet rs = null; 
 
    try { 
      conn = DBHelper.getConnection(); 
      String sql = "select * from items";// sql 語(yǔ)句 
      ps = conn.prepareStatement(sql); 
      rs = ps.executeQuery(); 
      // 將查詢的結(jié)果依次加入集合 
      while (rs.next()) { 
        Items item = new Items(); 
        item.setId(rs.getInt("id")); 
        item.setName(rs.getString("name")); 
        item.setCity(rs.getString("city")); 
        item.setPrice(rs.getDouble("price")); 
        item.setPicture(rs.getString("picture")); 
        item.setNumber(rs.getInt("number")); 
        list.add(item); 
      } 
    } catch (SQLException e) { 
 
      e.printStackTrace(); 
    } finally { 
      // 關(guān)閉資源 
      if (rs != null) { 
        try { 
          rs.close(); 
        } catch (SQLException e) { 
          // TODO Auto-generated catch block 
          e.printStackTrace(); 
        } 
      } 
      if (ps != null) { 
        try { 
          ps.close(); 
        } catch (SQLException e) { 
          // TODO Auto-generated catch block 
          e.printStackTrace(); 
        } 
      } 
 
    } 
    return list; 
  } 
 
  // 根據(jù)商品編號(hào)獲取商品資料 
 
  public Items getItemById(int id) { 
    Items item = new Items(); 
    Connection con = null; 
    PreparedStatement ps = null; 
    ResultSet rs = null; 
    String sql = "select * from items where id = ?"; 
    try { 
      con = DBHelper.getConnection(); 
      ps = con.prepareStatement(sql); 
      ps.setInt(1, id); 
      rs = ps.executeQuery(); 
      // 如果找到該id 為item對(duì)象初始化 
      if (rs.next()) { 
        item.setId(rs.getInt("id")); 
        item.setName(rs.getString("name")); 
        item.setCity(rs.getString("city")); 
        item.setPrice(rs.getDouble("price")); 
        item.setPicture(rs.getString("picture")); 
        item.setNumber(rs.getInt("number")); 
      } 
 
    } catch (SQLException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
    } finally { 
      // 關(guān)閉資源 
      if (rs != null) { 
        try { 
          rs.close(); 
        } catch (SQLException e) { 
          // TODO Auto-generated catch block 
          e.printStackTrace(); 
        } 
      } 
      if (ps != null) { 
        try { 
          ps.close(); 
        } catch (SQLException e) { 
          // TODO Auto-generated catch block 
          e.printStackTrace(); 
        } 
      } 
    } 
    return item; 
  } 
 
  // 根據(jù)cookie 獲得瀏覽的最后三個(gè)商品 
  public ArrayList<Items> getHistoryView(String cookie) { 
    ArrayList<Items> list = new ArrayList<Items>(); 
    String ids[] = cookie.split(","); 
    int counts = 3;// 瀏覽的最后三條記錄 
    if (ids != null && ids.length > 0) { 
      for (int i = ids.length - 1; i >= 0 && i > ids.length - counts - 1; i--) { 
        Items item = getItemById(Integer.parseInt(ids[i])); 
        /* 
         * 首先判斷集合中是否存在當(dāng)前物品 如果存在 counts+1 多讀取一次（保證list集合中有3個(gè)對(duì)象） 不添加此物品 
         */ 
        if (list.contains(item)) { 
          counts++; 
          continue; 
        } 
        list.add(item); 
      } 
    } 
    return list; 
  } 
}

商品的實(shí)體類 Items

package entity; 
 
public class Items { 
  private int id; 
  private String name; 
  private String city; 
  private double price; 
  private int number; 
  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 double getPrice() { 
    return price; 
  } 
 
  public void setPrice(double price) { 
    this.price = price; 
  } 
 
  public int getNumber() { 
    return number; 
  } 
 
  public void setNumber(int number) { 
    this.number = number; 
  } 
 
  public String getPicture() { 
    return picture; 
  } 
 
  public void setPicture(String picture) { 
    this.picture = picture; 
  } 
   
  @Override 
  public int hashCode() { 
    // TODO Auto-generated method stub 
    return this.getId()+this.getName().hashCode(); 
  } 
  @Override 
  public boolean equals(Object obj) { 
    if(this==obj) 
    { 
      return true; 
    } 
    else 
    { 
      if(obj instanceof Items) 
      { 
        Items item=(Items) obj; 
        if(this.getId()==item.getId()&&this.getName().equals(item.getName())) 
        { 
          return true; 
        } 
      } 
    } 
    return false; 
  } 
}

在這里重寫(xiě)了hasCode和equals方法來(lái)修改比較方式（所有的item都是一個(gè)新的對(duì)象即使兩個(gè)商品的內(nèi)容全部一樣也不會(huì)相等。所以要修改比較方式）
因?yàn)閷?duì)于瀏覽記錄而言我們不能通過(guò)刷新當(dāng)前商品瀏覽記錄全部都是該商品我們只要保證該商品在瀏覽記錄中只有一個(gè)即可
所以在dao層中的getHistoryView方法有這句代碼

<span style="white-space:pre">       </span>if (list.contains(item)) { 
          counts++; 
          continue; 
        }

然后是工具類
DBHelpher 單例模式獲得connection對(duì)象

package util; 
 
import java.sql.Connection; 
import java.sql.DriverManager; 
import java.sql.SQLException; 
 
public class DBHelper { 
  private static final String driver = "com.mysql.jdbc.Driver"; 
  private static final String url = "jdbc:mysql://localhost:3306/shopping?useUnicode=true&charcterEncoding=UTF-8"; 
  private static final String username = "root"; 
  private static final String password = "123"; 
  private static Connection con = null; 
  // 靜態(tài)塊代碼負(fù)責(zé)加載驅(qū)動(dòng) 
  static { 
    try { 
      Class.forName(driver); 
    } catch (ClassNotFoundException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
    } 
  } 
 
  public static Connection getConnection() { 
 
    if (con == null) { 
      try { 
        con = DriverManager.getConnection(url, username, password); 
      } catch (SQLException e) { 
        // TODO Auto-generated catch block 
        e.printStackTrace(); 
      } 
    } 
    return con; 
  } 
}

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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