Using Log4Net logging NetCore

You need to install the package
log4net version 2.0.8
Microsoft.Extensions.Logging.Log4Net.AspNetCore version 2.2.6
Add a profile in the Program

 public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
            .ConfigureLogging((context, loggingBuilder) =>
            {
                loggingBuilder.AddFilter("System", LogLevel.Warning); //过滤掉 以system开头的 警告以下的错误
                loggingBuilder.AddFilter("Microsoft", LogLevel.Warning);//过滤掉系统默认的一些日志
                //Microsoft.Extensions.Logging.Log4Net.AspNetCore  版本2.2.6
                loggingBuilder.AddLog4Net();
            })
                .UseStartup<Startup>();

Log4Net configuration file, it willCopy to Output DirectoryProperty toFu always copy

<?xml version="1.0" encoding="utf-8"?>
<log4net>
	<!-- Define some output appenders -->
	<appender name="rollingAppender" type="log4net.Appender.RollingFileAppender">
		<file value="log\log.txt" />

		<!--追加日志内容-->
		<appendToFile value="true" />

		<!--防止多线程时不能写Log,官方说线程非安全-->
		<lockingModel type="log4net.Appender.FileAppender+MinimalLock" />

		<!--可以为:Once|Size|Date|Composite-->
		<!--Composite为Size和Date的组合-->
		<rollingStyle value="Composite" />

		<!--当备份文件时,为文件名加的后缀-->
		<datePattern value="yyyyMMdd.TXT" />

		<!--日志最大个数,都是最新的-->
		<!--rollingStyle节点为Size时,只能有value个日志-->
		<!--rollingStyle节点为Composite时,每天有value个日志-->
		<maxSizeRollBackups value="20" />

		<!--可用的单位:KB|MB|GB-->
		<maximumFileSize value="3MB" />

		<!--置为true,当前最新日志文件名永远为file节中的名字-->
		<staticLogFileName value="true" />

		<!--输出级别在INFO和ERROR之间的日志-->
		<filter type="log4net.Filter.LevelRangeFilter">
			<param name="LevelMin" value="ALL" />
			<param name="LevelMax" value="FATAL" />
		</filter>

		<!--必须结合起来用,第一个只过滤出WARN,第二个拒绝其它其它日志输出-->
		<!--
		<filter type="log4net.Filter.LevelMatchFilter">
			<param name="LevelToMatch" value="WARN" />
		</filter>
		<filter type="log4net.Filter.DenyAllFilter" />-->

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

  
	<!-- levels: OFF > FATAL > ERROR > WARN > INFO > DEBUG  > ALL -->
	<root>
		<priority value="ALL"/>
		<level value="ALL"/>
		<appender-ref ref="rollingAppender" />
	</root>
</log4net>

Injection in the StartUpILoggerFactory

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory factory)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }
            ILogger<Startup> logger = factory.CreateLogger<Startup>();
            logger.LogError("this is ILoggerFactory ");

            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseCookiePolicy();

            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Home}/{action=Index}/{id?}");
            });
        }

Injection controllerILoggeror ILoggerFactory

     private readonly ILogger<HomeController> logger = null;
        private readonly ILoggerFactory loggerFactory = null;

        public HomeController(ILogger<HomeController> _logger, ILoggerFactory _loggerFactory)
        {
            logger = _logger;
            loggerFactory = _loggerFactory;
        } 

        public IActionResult Index()
        {
            logger.LogInformation("Home/Index 的ILogger注入");
            loggerFactory.CreateLogger<HomeController>().LogWarning("Home/Index 的ILoggerFactory注入");
            return View();
        }