Log4日志搭建

第一步 引用nuget包

第二步 建一个Log4NetExtensions类 用于初始化log4net

  public static class Log4NetExtensions
    {
        //新建一个静态类，写一个扩展方法 UseLog4Net() ，用于 log4net 初始化。
        public static IHostBuilder UseLog4Net(this IHostBuilder hostBuilder)
        {
            var log4netRepository = LogManager.GetRepository(Assembly.GetEntryAssembly());
            XmlConfigurator.Configure(log4netRepository, new FileInfo("log4net.config"));
            return hostBuilder;
        }
    }

第三步 建一个log4net.config文件 配置日志的输出

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
  </configSections>
  <log4net debug="false">

    <appender name="info" type="log4net.Appender.RollingFileAppender,log4net">
      <param name="File" value="log4net/info/" />
      <param name="AppendToFile" value="true" />
      <param name="MaxSizeRollBackups" value="-1"/>
      <param name="MaximumFileSize" value="5MB"/>
      <param name="RollingStyle" value="Composite" />
      <param name="DatePattern" value="yyyyMMdd\\HH&quot;.log&quot;" />
      <param name="StaticLogFileName" value="false" />
      <layout type="log4net.Layout.PatternLayout,log4net">
        <param name="ConversionPattern" value="%n
{
 &quot;system&quot;: &quot;Meowv.Blog&quot;,
 &quot;datetime&quot;: &quot;%d&quot;,
 &quot;description&quot;: &quot;%m&quot;,
 &quot;level&quot;: &quot;%p&quot;,
 &quot;info&quot;: &quot;%exception&quot;
}" />
      </layout>
      <filter type="log4net.Filter.LevelRangeFilter">
        <levelMin value="INFO" />
        <levelMax value="INFO" />
      </filter>
    </appender>

    <appender name="error" type="log4net.Appender.RollingFileAppender,log4net">
      <param name="File" value="log4net/error/" />
      <param name="AppendToFile" value="true" />
      <param name="MaxSizeRollBackups" value="-1"/>
      <param name="MaximumFileSize" value="5MB"/>
      <param name="RollingStyle" value="Composite" />
      <param name="DatePattern" value="yyyyMMdd\\HH&quot;.log&quot;" />
      <param name="StaticLogFileName" value="false" />
      <layout type="log4net.Layout.PatternLayout,log4net">
        <param name="ConversionPattern" value="%n
{
 &quot;system&quot;: &quot;Meowv.Blog&quot;,
 &quot;datetime&quot;: &quot;%d&quot;,
 &quot;description&quot;: &quot;%m&quot;,
 &quot;level&quot;: &quot;%p&quot;,
 &quot;info&quot;: &quot;%exception&quot;
}" />
      </layout>
      <filter type="log4net.Filter.LevelRangeFilter">
        <levelMin value="ERROR" />
        <levelMax value="ERROR" />
      </filter>
    </appender>

    <root>
      <level value="ALL"></level>
      <appender-ref ref="info"/>
      <appender-ref ref="error"/>
    </root>

  </log4net>

</configuration>

第四步 host注册日志

  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>();
                    //使用日志
                }).UseLog4Net();
    }

第五步 使用

  public class HomeController : Controller
    {
        private readonly ILog _log;
        //注入构造函数
        public HomeController(ILogger<HomeController> logger)
        {
            _log = LogManager.GetLogger(typeof(HomeController));
        }

        public IActionResult Index()
        {
            //消息日志
            _log.Info("hello world");
            //错误日志
            _log.Error("你好呀");

            return View();
        }
    }

最终效果