网站在线人数统计（貌似不能写入文件，有错请指正，谢谢！）

来源：互联网发布：数据库唯一约束编辑：程序博客网时间：2024/04/28 03:24

using System;
using System.IO;

namespace Application_Count
{
public class Global : System.Web.HttpApplication
{

        protected void Application_Start(object sender, EventArgs e)
        {
            Application["strPath"]=Server.MapPath("~/CountFile/visitCount.txt");
            //Application["strPath"]=Server.MapPath(null)+@"/CountFile/visitCount.txt";
            //对比格式，两种都可以
            string strPath = Application["strPath"].ToString();//将路径保存在变量中
            if( System.IO.File.Exists(strPath))//若文件存在
            {
                //读取文件
                StreamReader sr=new StreamReader (strPath);
                string strCount=sr.ReadToEnd();//从头读到尾
                if(strCount!=null)
                {
                    Application["Count"]=Convert.ToInt32(strCount);//保存状态为当前值
                }
                else
                {
                    Application["Count"]=0;
                }
            }
            else //文件不存在时
            {
                //创建一个文件
                {
                    StreamWriter sw=File.CreateText(strPath);//创建一个文本文件并写入指定路径
                     Application["Count"]=0;
                    sw.Write( Application["Count"].ToString());//将计数量存在文件文本中
                    sw.Close();
                }
            }

}

        protected void Session_Start(object sender, EventArgs e)
        {
            //string strPath = Application["strPath"].ToString();
            //StringWriter sw = new StringWriter();
            //string类型不能在构造函数中带参，就没有了写入的路径，所以选择StringBuilder
            System.Text.StringBuilder strPath = new System.Text.StringBuilder(Application["strPath"].ToString());
            Application.Lock();
            Application["Count"] = Convert.ToInt32(Application["Count"]) + 1;
            StringWriter sw = new StringWriter(strPath);
            sw.Write(Application["Count"].ToString());//将新的访问量存在文件中
            sw.Close();
            Application.UnLock();
        }

protected void Application_BeginRequest(object sender, EventArgs e)
{

}

protected void Application_AuthenticateRequest(object sender, EventArgs e)
{

}

protected void Application_Error(object sender, EventArgs e)
{

}

        protected void Session_End(object sender, EventArgs e)
        {
            System.Text.StringBuilder strPath = new System.Text.StringBuilder(Application["strPath"].ToString());
            //如果要修改字符串而不创建新对象，可以用StringBuilder类（在同一处内存修改）
            Application.Lock();
            Application["Count"] = Convert.ToInt32(Application["Count"]) - 1;
            StringWriter sw = new StringWriter(strPath);
            sw.Write(Application["Count"].ToString());//将新的访问量存在文件中
            sw.Close();
            Application.UnLock();
        }

protected void Application_End(object sender, EventArgs e)
{

}
}
}

注：先创建一个Global文件，再在根目录下添加名为CountFile的文件夹。