<?xml version="1.0" encoding="utf-8" ?>

 <configuration>

   <!-- This section contains the log4net configuration settings -->

   <log4net>

     <appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender">

       <layout type="log4net.Layout.PatternLayout" value="%date [%thread] %-5level %logger - %message%newline" />

     </appender>

     <appender name="FileAppender" type="log4net.Appender.FileAppender">

       <file value="log-file.log" />

       <appendToFile value="true" />

       <layout type="log4net.Layout.PatternLayout">

         <conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />

       </layout>

     </appender>

     <appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">

       <file value="logfile/" />   //指定日志文件保存的目录

       <appendToFile value="true" />

       <rollingStyle value="Composite" />

       <staticLogFileName value="false" />

       <datePattern value="yyyyMMdd'.log'" />

       <maxSizeRollBackups value="10" />

       <maximumFileSize value="1MB" />

       <layout type="log4net.Layout.PatternLayout">

         <conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />

       </layout>

     </appender>

     <!-- Setup the root category, add the appenders and set the default level -->

     <root>

       <level value="ALL" />

       <appender-ref ref="ConsoleAppender" />

       <appender-ref ref="FileAppender" />

       <appender-ref ref="RollingLogFileAppender" />

     </root>

   </log4net>

 </configuration>

3.在StartUp.cs中配置log4Net

         //为StartUp.cs添加属性

         public static ILoggerRepository repository { get; set; }

         public Startup(IConfiguration configuration, IHostingEnvironment env)

         {

             Configuration = configuration;

             //log4net

             repository = LogManager.CreateRepository("NETCoreRepository");

             //指定配置文件

             XmlConfigurator.Configure(repository, new FileInfo("log4net.config"));

         }

4.在程序中中使用log4Net写日志

下面是注入到控制器中的示例

     public class HomeController : Controller

     {

         //log4Net

         private ILog log;

         public UploadFilesController(IHostingEnvironment hostingEnv)

         {

             //log4Net

             this.log = LogManager.GetLogger(Startup.repository.Name, typeof(HomeController));

         }

         public IActionResult Index()

         {

             var name = message.Name;

             var age = message.Age;

             log.Error("error message");

             return View();

         }

 }