在微软发布的ASP.NET Core 中给了一种默认的日志配置选择，那么当我们使用其他的日志中间件是如何配置呢？如下：

1、使用NutGet 获取日志库：Microsoft.Extensions.Logging.Log4Net.AspNetCore  和 Log4Net库

2、配置Program.cs

public class Program
    {
        public static void Main(string[] args)
        {
            CreateHostBuilder(args).Build().Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                })
            .ConfigureLogging((hosttingContext,logging)=>
            {
                logging.AddFilter("System", LogLevel.Warning);
                logging.AddFilter("Microsoft", LogLevel.Warning);
                logging.AddLog4Net();
            })
            
            ;
    }

 3、配置Startup.cs文件

  public void Configure(IApplicationBuilder app, IWebHostEnvironment env, ILoggerFactory loggerFactory)
        {
            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();
            }
            loggerFactory.AddLog4Net();
            app.UseHttpsRedirection();
            app.UseStaticFiles();

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllerRoute(
                    name: "default",
                    pattern: "{controller=Home}/{action=Index}/{id?}");
            });
        }

3、新建配置文件：

<?xml version="1.0" encoding="utf-8" ?>
<log4net>
  <appender name="DebugAppender" type="log4net.Appender.DebugAppender" >
    <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value="%date [%thread] %-5level %logger - %message%newline" />
    </layout>
  </appender>
  <!--指定日记记录方式，以滚动文件的方式（文件记录）-->
  <appender name="RollingFile" type="log4net.Appender.RollingFileAppender">
    <!--日志路径-->
    <file value="Log/" />
    <!--是否是向文件中追加日志-->
    <appendToFile value="true" />
    <!--log保留天数-->
    <param name= "MaxSizeRollBackups" value= "10"/>
    <!--每个文件最大1M-->
    <param name="maximumFileSize" value="1MB" />
    <!--日志根据日期滚动-->
    <param name="RollingStyle" value="Date" />
    <!--日志文件名格式为:logs_20080831.log-->
    <param name="DatePattern" value="&quot;logs_&quot;yyyyMMdd&quot;.log&quot;" />
    <!--日志文件名是否是固定不变的-->
    <param name="StaticLogFileName" value="false" />
    <!--布局-->
    <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value="%date %5level %logger.%method [%line] - MESSAGE: %message%newline %exception" />
    </layout>
  </appender>
  <root>
    <level value="ALL"/>
    <appender-ref ref="DebugAppender" />
    <appender-ref ref="RollingFile" />
  </root>
</log4net>