demo地址：https://github.com/PuzzledAlien/log4net_demo

準備

• log4net 最新版本是2.0.8
• VS2017
• .Net Core 2.2
• 測試電腦配置 windows10 64位 4核CPU 16G記憶體

log4net官網引導文檔 ：http://logging.apache.org/log4net/release/manual/introduction.html

配置和代碼

log4net.config配置如下

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
  </configSections>
  <log4net>
    <appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
      <!--日誌路徑-->
      <param name= "File" value= ".\App_Log\servicelog\"/>
      <!--是否是向文件中追加日誌-->
      <param name= "AppendToFile" value= "true"/>
      <!--log保留天數-->
      <param name= "MaxSizeRollBackups" value= "10"/>
      <!--每個log文件最大是2M，如果超過2M將重新創建一個新的log文件，並將原來的log文件備份。-->
      <maximumFileSize value="2MB" />
      <!--日誌文件名是否是固定不變的-->
      <param name= "StaticLogFileName" value= "false"/>
      <!--日誌文件名格式為:2008-08-31-12.log-->
      <param name= "DatePattern" value= "yyyy-MM-dd-HH-mm&quot;.read.log&quot;"/>
      <!--日誌根據日期滾動-->
      <param name= "RollingStyle" value= "Date"/>
      <layout type="log4net.Layout.PatternLayout">
        <param name="ConversionPattern" value="%d [%t] %-5p %c - %m%n %loggername" />
      </layout>
      <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
    </appender>
    <!-- 控制台前臺顯示日誌 -->
    <appender name="ManagedColoredConsoleAppender" type="log4net.Appender.ManagedColoredConsoleAppender">
      <mapping>
        <level value="ERROR" />
        <foreColor value="Red" />
      </mapping>
      <mapping>
        <level value="Info" />
        <foreColor value="Green" />
      </mapping>
      <mapping>
        <level value="DEBUG" />
        <foreColor value="Blue" />
      </mapping>
      <mapping>
        <level value="WARN" />
        <foreColor value="Yellow" />
      </mapping>
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%n%date{HH:mm:ss,fff} [%-5level] %m" />
      </layout>
      <filter type="log4net.Filter.LevelRangeFilter">
        <param name="LevelMin" value="DEBUG" />
        <param name="LevelMax" value="Fatal" />
      </filter>
    </appender>
    <root>
      <!--(高) OFF > FATAL > ERROR > WARN > INFO > DEBUG > ALL (低) -->
      <level value="ALL" />
      <appender-ref ref="ManagedColoredConsoleAppender"/>
      <appender-ref ref="RollingLogFileAppender"/>
    </root>
  </log4net>
</configuration>

添加引用

using log4net;
using log4net.Config;
using log4net.Repository;

代碼如下：

        private static ILoggerRepository _loggerRepository;
        static void Main(string[] args)
        {
            _loggerRepository = LogManager.CreateRepository("ConsoleApp3");
            XmlConfigurator.ConfigureAndWatch(_loggerRepository, new FileInfo("log4net.config"));
            var log = LogManager.GetLogger(_loggerRepository.Name, typeof(Program));

            const int numberOfCycles = 20000;

            var sw = Stopwatch.StartNew();
            for (var i = 0; i < numberOfCycles; i++)
            {
                log.InfoFormat("testNum: {0} ", i);
            }
            sw.Stop();

            Console.WriteLine();
            Console.WriteLine("Ellapsed: {0}, numPerSec: {1}", sw.ElapsedMilliseconds, numberOfCycles / (sw.ElapsedMilliseconds / (double)1000));

            Console.WriteLine("Hello World!");

            Console.ReadKey();
        }

執行結果：
本地寫log文本日誌和Console列印日誌的時間14720毫秒 一秒鐘寫日誌1359條

Ellapsed: 14720, numPerSec: 1358.69565217391