NET8使用Microsoft.Extensions.Logging,在Nlog和log4net中随意切换

LoggerHelper类:

 public static class LoggerHelper
 {
     private static ILoggerFactory _loggerFactory;
     private static readonly ConcurrentDictionary<Type, ILogger> _loggers = new();

     /// <summary>
     /// 初始化日志工厂（Program.cs 里调用）
     /// </summary>
     public static void Init(ILoggerFactory loggerFactory)
     {
         _loggerFactory = loggerFactory ?? throw new ArgumentNullException(nameof(loggerFactory));
     }

     /// <summary>
     /// 获取某个类型的 Logger
     /// </summary>
     public static ILogger GetLogger(Type type) =>
         _loggers.GetOrAdd(type, t => _loggerFactory.CreateLogger(t));

     /// <summary>
     /// 获取调用类的 Logger（自动推断）
     /// </summary>
     private static Type GetCallingType()
     {
         var frame = new StackFrame(2, false); // 2 层上调用
         return frame.GetMethod()?.DeclaringType ?? typeof(object);
     }

     private static ILogger GetLoggerForCallingType() =>
         GetLogger(GetCallingType());

     // -------- 快捷方法 --------
     public static void Debug(string msg) => GetLoggerForCallingType().LogDebug(msg);
     public static void Info(string msg) => GetLoggerForCallingType().LogInformation(msg);
     public static void Warn(string msg) => GetLoggerForCallingType().LogWarning(msg);
     public static void Error(string msg, Exception ex = null) =>
         GetLoggerForCallingType().LogError(ex, msg);
     public static void Fatal(string msg, Exception ex = null) =>
         GetLoggerForCallingType().LogCritical(ex, msg);
 }

Main方法中:

  var host = Host.CreateDefaultBuilder()
      .ConfigureServices((context, services) =>
      {
          services.AddSingleton<MainForm>();
          //services.AddSingleton<OtherService>();
      })
      .ConfigureLogging(logging =>
      {
          logging.ClearProviders();
          //logging.AddLog4Net("log4net.config");
          logging.AddNLog(); // 不要 log4net
      })
      .Build();

  var loggerFactory = host.Services.GetRequiredService<ILoggerFactory>();
  LoggerHelper.Init(loggerFactory);

注意这里: 可任意切换log4net和Nlog

  logging.AddLog4Net("log4net.config");
OR
  //logging.AddNLog(); // 不要 log4net

在其他代码处写下面的就可以记录日志了:

  LoggerHelper.Info("配置加载完成");
  LoggerHelper.Debug("Debug日志测试");
  LoggerHelper.Error("Error日志测试");

当然别忘记config:

log4net.config始终复制到目录:内容如下:

<?xml version="1.0" encoding="utf-8" ?>
<log4net>
    <!-- Info 日志 -->
    <appender name="InfoAppender" type="log4net.Appender.RollingFileAppender">
        <file value="Logs\\info\\" />
        <appendToFile value="true" />
        <rollingStyle value="Date" />
        <datePattern value="yyyy-MM-dd'.log'" />
        <staticLogFileName value="false" />
        <layout type="log4net.Layout.PatternLayout">
            <conversionPattern value="[%date] %-5level %logger - %message%newline" />
        </layout>
        <filter type="log4net.Filter.LevelRangeFilter">
            <levelMin value="INFO" />
            <levelMax value="INFO" />
        </filter>
    </appender>

    <!-- Error 日志 -->
    <appender name="ErrorAppender" type="log4net.Appender.RollingFileAppender">
        <file value="Logs\\error\\" />
        <appendToFile value="true" />
        <rollingStyle value="Date" />
        <datePattern value="yyyy-MM-dd'.log'" />
        <staticLogFileName value="false" />
        <layout type="log4net.Layout.PatternLayout">
            <conversionPattern value="[%date] %-5level %logger - %message%newline" />
        </layout>
        <filter type="log4net.Filter.LevelRangeFilter">
            <levelMin value="ERROR" />
            <levelMax value="FATAL" />
        </filter>
    </appender>

    <!-- Debug 日志 -->
    <appender name="DebugAppender" type="log4net.Appender.RollingFileAppender">
        <file value="Logs\\debug\\" />
        <appendToFile value="true" />
        <rollingStyle value="Date" />
        <datePattern value="yyyy-MM-dd'.log'" />
        <staticLogFileName value="false" />
        <layout type="log4net.Layout.PatternLayout">
            <conversionPattern value="[%date] %-5level %logger - %message%newline" />
        </layout>
        <filter type="log4net.Filter.LevelRangeFilter">
            <levelMin value="DEBUG" />
            <levelMax value="DEBUG" />
        </filter>
    </appender>

    <!-- 根日志 -->
    <root>
        <level value="DEBUG" />
        <appender-ref ref="InfoAppender" />
        <appender-ref ref="ErrorAppender" />
        <appender-ref ref="DebugAppender" />
    </root>
</log4net>

NLog.config始终复制到目录:内容如下:

<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      autoReload="true"
      throwConfigExceptions="true">

    <targets>
        <!-- Info 日志 -->
        <target xsi:type="File" name="infoFile"
                fileName="Logs/Info-N/${shortdate}.log"
                layout="[${longdate}] ${level} ${logger} - ${message} ${exception}" />

        <!-- Error 日志 -->
        <target xsi:type="File" name="errorFile"
                fileName="Logs/Error-N/${shortdate}.log"
                layout="[${longdate}] ${level} ${logger} - ${message} ${exception}" />

        <!-- Debug 日志 -->
        <target xsi:type="File" name="debugFile"
                fileName="Logs/Debug-N/${shortdate}.log"
                layout="[${longdate}] ${level} ${logger} - ${message} ${exception}" />
    </targets>

    <rules>
        <!-- Debug 日志写到 Debug 文件 -->
        <logger name="*" minlevel="Debug" maxlevel="Debug" writeTo="debugFile" />

        <!-- Info 日志写到 Info 文件 -->
        <logger name="*" minlevel="Info" maxlevel="Info" writeTo="infoFile" />

        <!-- Error 及以上写到 Error 文件 -->
        <logger name="*" minlevel="Error" writeTo="errorFile" />
    </rules>
</nlog>