我们在进行Web开发时经常会用到Session，用它去标识不同的会话，那么涉及到跨站点的时候如何实现Session共享呢？
通常的解决方案有：使用数据库、使用Cookies做中间桥等等。
下面介绍一种基于ASP.NET 2.0的，通过序列化和反序列化机制实现的一种解决方案。
首先看一下通常的服务器集群的网络拓扑结构：
利用序列化机制实现Session共享的原理：
1、Web Server 1的应用程序序列化Session信息为文本值（可以是Binary或Soap格式）
2、将序列化后的值写入文件，保存到File Server上
3、Web Server 2 对保存在File Server上的Session序列化后的值进行反序列化
4、在Web Server 2上重新构建Session值
下面我们来详细看看实现代码，分以下几个步骤：
1、创建一个类库工程：ShareSession
引入以下的命名空间：
Code
System.configuration
System.Runtime.Serialization.Formatters.Soap
System.Web
2、创建一个类：SessionEntity
代码如下：
Code
using System;
using System.Collections.Generic;
using System.Text;
using System.Collections;
namespace ShareSession
{
/**//* *****************************
*
* Author : Xiaojun Liu
* Create Date : 2007.11.09
* Description :
*
* *****************************
*/
[Serializable]
public class SessionEntity
{
[NonSerialized]
public string AUTH_GUID = "";
private Hashtable _HtShareSession;
public Hashtable HtShareSession
{
get
{
return this._HtShareSession;
}
set
{
this._HtShareSession = value;
}
}
public SessionEntity(string guid)
{
this.AUTH_GUID = guid;
}
}//
}//
3、创建一个序列化、反序列化操作的类：ShareSessionFormatter
代码如下：
Code
using System;
using System.Web;
using System.Data;
using System.Collections.Generic;
using System.Text;
using System.Runtime.Serialization.Formatters.Soap;
using System.Runtime.Serialization.Formatters.Binary;
using System.Collections;
using System.IO;
namespace ShareSession
{
/**//* *****************************
*
* Author : Xiaojun Liu
* Create Date : 2007.11.09
* Description :
*
* *****************************
*/
/**//// <summary>
/// 格式化操作器
/// </summary>
public class ShareSessionFormatter
{
private static string _ShareSessionPath = System.Configuration.ConfigurationManager.AppSettings["ShareSessionPath"].ToString();
/**//// <summary>
/// 序列化格式器类型
/// </summary>
public enum FormatterType
{
Binary,
Soap
};
/**//// <summary>
/// 执行序列化
/// </summary>
/// <param name="formatterType">类型</param>
public static void Serialize(FormatterType formatterType)
{
if (HttpContext.Current.Session["AUTH_GUID"] == null)
{
HttpContext.Current.Session["AUTH_GUID"] = Guid.NewGuid().ToString();
}
Hashtable ht = new Hashtable();
//遍历Session
foreach (string key in HttpContext.Current.Session.Contents.Keys)
{
ht.Add(key, HttpContext.Current.Session[key]);
}
/**/////执行序列化
switch (formatterType)
{
case FormatterType.Binary:
BinarySerialize(ht);
break;
case FormatterType.Soap:
SoapSerialize(ht);
break;
default:
break;
}
}
/**//// <summary>
/// 按照Binary格式序列化
/// </summary>
/// <param name="ht"></param>
private static void BinarySerialize(Hashtable ht)
{
string guid = HttpContext.Current.Session["AUTH_GUID"].ToString();
SessionEntity obj = new SessionEntity(guid);
obj.HtShareSession = ht;
// 创建一个文件guid.xml
Stream stream = File.Open(_ShareSessionPath + guid + ".xml", FileMode.Create);
BinaryFormatter formatter = new BinaryFormatter();
//执行序列化
formatter.Serialize(stream, obj);
stream.Close();
// 将对象置空
obj = null;
}
/**//// <summary>
/// 按照Soap格式序列化
/// </summary>
/// <param name="ht"></param>
private static void SoapSerialize(Hashtable ht)
{
string guid = HttpContext.Current.Session["AUTH_GUID"].ToString();
SessionEntity obj = new SessionEntity(guid);
obj.HtShareSession = ht;
// 创建一个文件guid.xml
Stream stream = File.Open(_ShareSessionPath + guid + ".xml", FileMode.Create);
SoapFormatter formatter = new SoapFormatter();
//执行序列化
formatter.Serialize(stream, obj);
stream.Close();
// 将对象置空
obj = null;
}
/**//// <summary>
/// 反序列化
/// </summary>
/// <param name="formatterType">传送端的Session["AUTH_GUID"]</param>
/// <param name="guid"></param>
public static void Deserialize(FormatterType formatterType, string guid)
{
switch (formatterType)
{
case FormatterType.Binary:
BinaryDeserialize(guid);
break;
case FormatterType.Soap:
SoapDeserialize(guid);
break;
default:
break;
}
}
/**//// <summary>
/// 以Binary方式反序列化
/// </summary>
private static void BinaryDeserialize(string guid)
{
SessionEntity obj = new SessionEntity(guid);
// 打开文件guid.xml
Stream stream = File.Open(_ShareSessionPath + guid + ".xml", FileMode.Open);
BinaryFormatter formatter = new BinaryFormatter();
obj = (SessionEntity)formatter.Deserialize(stream);
stream.Close();
Hashtable ht = obj.HtShareSession;
obj = null;
//遍历ht，生成Session
CreateSession(ht);
}
/**//// <summary>
/// 以Soap方式反序列化
/// </summary>
private static void SoapDeserialize(string guid)
{
SessionEntity obj = new SessionEntity(guid);
// 打开文件guid.xml
Stream stream = File.Open(_ShareSessionPath + guid + ".xml", FileMode.Open);
SoapFormatter formatter = new SoapFormatter();
obj = (SessionEntity)formatter.Deserialize(stream);
stream.Close();
Hashtable ht = obj.HtShareSession;
obj = null;
//遍历ht，生成Session
CreateSession(ht);
}
/**//// <summary>
/// 遍历Hashtable，同时创建Session
/// </summary>
/// <param name="ht"></param>
private static void CreateSession(Hashtable ht)
{
foreach (DictionaryEntry de in ht)
{
HttpContext.Current.Session[de.Key.ToString()] = de.Value;
}
}
}//
}//
4、编译项目，生成ShareSession.dll
5、把ShareSession.dll引入Web Server 1上的应用程序中，同时在Web.config文件中增加配置字节
代码如下：
<!-- Session信息序列化后保存路径 -->
<add key="ShareSessionPath" value="C:\ShareSession\"/>
6、在Web Server 1上的应用程序中新建一个页面，功能是初始化Session，然后把Session信息序列化，代码如下：
前台代码：
<%...@ Page Language="C#" AutoEventWireup="true" CodeFile="ShareSession.aspx.cs" Inherits="Front_Test_ShareSession" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "
http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="
http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Session共享</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Label ID="lHttp_Cookie" runat="server" Text=""></asp:Label>
<a href="
http://localhost:5000/Front/Test/ShareSession.aspx?AUTH_GUID=<%=AUTH_GUID %>">Go Other Web Site(port:5000)</a>
</div>
</form>
</body>
</html>
后台代码：
Code
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
public partial class Front_Test_ShareSession : System.Web.UI.Page
{
public string AUTH_GUID = "";
protected void Page_Load(object sender, EventArgs e)
{
Session.Clear();
Session.Abandon();
Session.Add("USER_ID", "2002");
Session.Add("USER_NAME", "Xiaojun Liu");
ShareSession.ShareSessionFormatter.Serialize(ShareSession.ShareSessionFormatter.FormatterType.Soap);
AUTH_GUID = Session["AUTH_GUID"].ToString();
}
}
7、在Web Server 2上进行第5步操作
8、在Web Server 2上的应用程序中新建一个页面，功能是反序列化，还原Session，同时读取Session信息进行测试，代码如下：
前台代码：
Code
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ShareSession.aspx.cs" Inherits="Front_Test_ShareSession" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Session共享</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Label ID="lHttp_Cookie" runat="server" Text=""></asp:Label>
</div>
</form>
</body>
</html>
后台代码：
Code
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
public partial class Front_Test_ShareSession : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
string guid = Request.Params["AUTH_GUID"].ToString();
ShareSession.ShareSessionFormatter.Deserialize(ShareSession.ShareSessionFormatter.FormatterType.Soap,guid);
Response.Write("USER_ID = "+Session["USER_ID"].ToString()+"<br />");
Response.Write("USER_NAME = "+Session["USER_NAME"].ToString()+"<br />");
Response.Write("AUTH_GUID = " + Session["AUTH_GUID"].ToString() + "<br />");
}
}
此例子只是提供了一种解决思路，在应用过程中应根据项目不同进行调整及详细设计。
