1、用文件记录，每次访问文件：死锁问题严重，资源耗费太大。
2、用数据库记录：访问损耗大。
3、用Global.asax和Timer实现统计：比较可取。
下面举个例子：
总的来说，要做个在线人数统计简单，但是要做在线名单并且保存用户的访问日志，就需要耗费比较多的系统资源，是否划算就难说了（我只看需求文档，其他不管...）；
前面用过的IHttpModule方法也不错
using System;
using System.ComponentModel;
using System.Web;
using System.Web.SessionState;
using System.Data;
using System.Data.OleDb;
namespace Butterfly{
/// <summary>
/// Global 的摘要说明。
/// </summary>
public class Global : System.Web.HttpApplication
{
private static System.Threading.Timer timer;
private const int interval = 1000 * 60 * 10;//检查在线用户的间隔时间
/// <summary>
/// 必需的设计器变量。
/// </summary>
private System.ComponentModel.IContainer components = null;
public Global()
{
InitializeComponent();
}
protected void Application_Start(Object sender, EventArgs e)
{
if (timer == null)
timer = new System.Threading.Timer(new System.Threading.TimerCallback(ScheduledWorkCallback),
sender, 0, interval);
DataTable userTable = new DataTable();
userTable.Columns.Add("UserID");//用户ID
userTable.Columns.Add("UserName");//用户姓名
userTable.Columns.Add("FirstRequestTime");//第一次请求的时间
userTable.Columns.Add("LastRequestTime");//最后一次请求的时间
userTable.Columns.Add("ClientIP");//
userTable.Columns.Add("ClientName");//
userTable.Columns.Add("ClientAgent");//
//userTable.Columns.Add("LastRequestPath");//最后访问的页面
userTable.PrimaryKey = new DataColumn[]{userTable.Columns[0]};
userTable.AcceptChanges();
Application.Lock();
Application["UserOnLine"] = userTable;
Application.UnLock();
}
protected void Session_Start(Object sender, EventArgs e)
{
}
protected void Application_BeginRequest(Object sender, EventArgs e)
{
}
protected void Application_EndRequest(Object sender, EventArgs e)
{
}
protected void Application_AcquireRequestState(Object sender, EventArgs e)
{
HttpApplication mApp = (HttpApplication)sender;
if(mApp.Context.Session == null) return;
if(mApp.Context.Session["UserID"]==null ) return;
string userID = mApp.Context.Session["UserID"].ToString();
DataTable userTable = (DataTable)Application["UserOnLine"];
DataRow curRow = userTable.Rows.Find(new object[]{userID});
if(curRow != null)
{
this.GetDataRowFromHttpApp(mApp,ref curRow);
}
else
{
DataRow newRow = userTable.NewRow();
this.GetDataRowFromHttpApp(mApp,ref newRow);
userTable.Rows.Add(newRow);
}
userTable.AcceptChanges();
Application.Lock();
Application["UserOnLine"] = userTable;
Application.UnLock();
}
protected void Application_AuthenticateRequest(Object sender, EventArgs e)
{
}
protected void Application_Error(Object sender, EventArgs e)
{
}
protected void Session_End(Object sender, EventArgs e)
{
}
protected void Application_End(Object sender, EventArgs e)
{
}
#region Web 窗体设计器生成的代码
/// <summary>
/// 设计器支持所需的方法 - 不要使用代码编辑器修改
/// 此方法的内容。
/// </summary>
private void InitializeComponent()
{
this.components = new System.ComponentModel.Container();
}
#endregion
private void GetDataRowFromHttpApp(HttpApplication mApp,ref DataRow mRow)
{
if(mApp.Context.Session == null) return;
if(mApp.Context.Session["UserID"]==null || mApp.Context.Session["UserName"]==null) return;
string userID = mApp.Context.Session["UserID"].ToString();
string userName = mApp.Context.Session["UserName"].ToString();
//string requestPath = mApp.Request.Path;
if(mRow["UserID"].ToString().Length<1)
{
mRow["UserID"] = userID;
mRow["UserName"] = userName;
mRow["FirstRequestTime"] = System.DateTime.Now;
mRow["ClientIP"] = mApp.Context.Request.UserHostAddress;
mRow["ClientName"] = mApp.Context.Request.UserHostName;
mRow["ClientAgent"] = mApp.Context.Request.UserAgent;
}
mRow["LastRequestTime"] = System.DateTime.Now;
//mRow["LastRequestPath"] = requestPath;
}
private void ScheduledWorkCallback (object sender)
{
string filter = "Convert(LastRequestTime,'System.DateTime') < Convert('" + System.DateTime.Now.AddSeconds(-interval/1000).ToString() + "','System.DateTime')";
DataTable userTable = (DataTable)Application["UserOnLine"];
DataRow[] lineOutUsers = userTable.Select(filter);
for(int i=0;i<lineOutUsers.Length;i++)
{
DataRow curRow = lineOutUsers[i];
//保存到数据库
curRow.Delete();
}
userTable.AcceptChanges();
Application.Lock();
Application["UserOnLine"] = userTable;
Application.UnLock();
}
}
}
补充：
在线人数比较好做，在线名单就不好做了，
另外，<sessionState> 设为InProc方式时才可以触发SessionEnd事件，