Log4Net根据不同的Logger名称，生成日志文件到不同的地方。

1.定义日志记录类

public class Log4NetLogger : ISystemLogger
   {
       static log4net.ILog securityLogger = log4net.LogManager.GetLogger("SecurityLog");
       static log4net.ILog sysLogger = log4net.LogManager.GetLogger("SystemLog");

       public SystemLogLevel LogLevel
       {
           get
           {
               if (ApplicationManager.SystemInfo.SystemLogLevel.HasValue)
               {
                   return (SystemLogLevel)ApplicationManager.SystemInfo.SystemLogLevel;
               }
               else
               {
                   return SystemLogLevel.None;
               }
           }
           set
           {
               ApplicationManager.UpdateLogLevel(value);
           }
       }

       /// <summary>
       /// 输出错误级别日志
       /// </summary>
       /// <param name="message">输出的消息</param>
       public void Error(string message)
       {
           //记录日志
           writeSysLog(SystemLogLevel.Error, message);
       }

       /// <summary>
       /// 输出警告级别日志
       /// </summary>
       /// <param name="message">输出的消息</param>
       public void Warning(string message)
       {
           //记录日志
           writeSysLog(SystemLogLevel.Warning, message);
       }

       /// <summary>
       /// 输出信息级别日志
       /// </summary>
       /// <param name="message">输出的消息</param>
       public void Info(string message)
       {
           //记录日志
           writeSysLog(SystemLogLevel.Info, message);
       }

       /// <summary>
       /// 输出调试级别日志
       /// </summary>
       /// <param name="message">输出的消息</param>
       public void Debug(string message)
       {
           //记录日志
           writeSysLog(SystemLogLevel.Debug, message);
       }

       /// <summary>
       /// 记录个资法案日志
       /// </summary>
       public void SecurityLog(string message)
       {
           writeSecurityLog(message);
       }

       /// <summary>
       /// 记录系统日志
       /// </summary>
       /// <param name="logLevel">日志级别</param>
       /// <param name="message">输出的消息</param>
       private void writeSysLog(SystemLogLevel logLevel, string message)
       {
           string format = "ClientIP={0},CurrentUser={1},Message={2}";
           ClientInfo clientInfo = WebServerHelper.CurrentClientInfo;
           string fullMsg = string.Format(format, clientInfo.UserHostAddress, WebServerHelper.CurrentUserID, message);
           if (LogLevel >= logLevel)
           {
               switch (logLevel)
               {
                   case SystemLogLevel.Debug:
                       sysLogger.Debug(fullMsg);
                       break;
                   case SystemLogLevel.Error:
                       sysLogger.Error(fullMsg);
                       break;
                   case SystemLogLevel.Info:
                       sysLogger.Info(fullMsg);
                       break;
                   case SystemLogLevel.Warning:
                       sysLogger.Warn(fullMsg);
                       break;
               }
           }
       }
       /// <summary>
       /// 记录个资法案日志
       /// </summary>
       /// <param name="message"></param>
       private void writeSecurityLog(string message)
       {
           string format = "ClientIP={0},CurrentUser={1},System={2},Message={3}";
           ClientInfo clientInfo = WebServerHelper.CurrentClientInfo;
           string fullMsg = string.Format(format, clientInfo.UserHostAddress, WebServerHelper.CurrentUserID,ApplicationManager.SystemCode, message);
           securityLogger.Info(fullMsg);
       }
   }

2.设置配制文件：

<configSections>
        <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler,log4net"/>
</configSections>
<log4net>
        <appender name="SystemLogAppender" type="log4net.Appender.RollingFileAppender">
            <file value="OA_Log/App_Log/" />
            <appendToFile value="true" />
            <rollingStyle value="Date" />
            <staticLogFileName value="false" />
            <datePattern value="yyyyMMdd&quot;.log&quot;" />
            <layout type="log4net.Layout.PatternLayout">
                <!--输出格式-->
                <conversionPattern value="%date %-5level %message%newline" />
            </layout>
            <filter type="log4net.Filter.LoggerMatchFilter">
                <loggerToMatch value="SystemLog" />
            </filter>
            <filter type="log4net.Filter.DenyAllFilter" />
        </appender>
        <appender name="SecurityLogAppender" type="log4net.Appender.RollingFileAppender">
            <file value="OA_Log/Access_Log/" />
            <appendToFile value="true" />
            <rollingStyle value="Date" />
            <staticLogFileName value="false" />
            <datePattern value="yyyyMMdd&quot;.log&quot;" />
            <layout type="log4net.Layout.PatternLayout">
                <!--输出格式-->
                <conversionPattern value="%date %-5level %message%newline" />
            </layout>
            <filter type="log4net.Filter.LoggerMatchFilter">
                <loggerToMatch value="SecurityLog" />
            </filter>
            <filter type="log4net.Filter.DenyAllFilter" />
        </appender>
        <root>
            <level value="ALL"/>
            <appender-ref ref="SystemLogAppender"/>
            <appender-ref ref="SecurityLogAppender"/>
        </root>
</log4net>

3.在Global.asax的Application_Start事件中加入初始化代码：

protected void Application_Start(object sender, EventArgs e)
{
           log4net.Config.XmlConfigurator.Configure();
}