1.下载log4net

2编写log4net的配置文件

　　3编写帮助类

using log4net;using System;using System.Collections.Generic;using System.IO;using System.Linq;using System.Reflection;using System.Text;using System.Text.RegularExpressions;using System.Threading.Tasks;using System.Web;namespace TestData.Common{    public static class HadleExcption    {        //判断是否是绝对路径        public static bool IsPhysicalPath(string Path)        {            string RegexString = @"\b[a-z]:\\.*";            MatchCollection Matchs = Regex.Matches(Path, RegexString, RegexOptions.IgnoreCase | RegexOptions.Compiled);            if (Matchs.Count > 0)                return true;            return false;        }        public static void WriteLog(this Exception ex, string message)        {            string _path = "";            if (!IsPhysicalPath("~/Config/lognet.config"))                _path = HttpContext.Current.Server.MapPath("~/Config");            else _path = "~/Config/lognet.config";            FileInfo info = null;            if (new DirectoryInfo(_path).Exists)            {                info = new FileInfo(_path + "/lognet.config");            }            log4net.Config.XmlConfigurator.ConfigureAndWatch(info);            log4net.ILog log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);            log.Info(message, ex);        }    }}