Log4Net在.NET Fromework和.NET Core中的使用

　　本文讨论的是在都需要使用Log4Net的前提下，因为.NET Core已经内置了日志服务，不使用Log4Net也是可以看到日志的.

　　一、区别

　　相同：

　　1，都需要引用log4net.dll。

　　不同：

　　1，需要格式化日志输出方式的，它们中的Log4Net.config配置文件格式是不同的。

　　2，.NET Core还需要引用Microsoft.Extensions.Logging.Log4Net.AspNetCore.dll。

　　3，使用方式不同，.NET Framework一般是需要借助帮助类库的，.NET Core是可以直接使用依赖注入，也可以使用帮助类库。

　　二、使用方式

　　1，.NET Framework

using log4net;
using System;
using System.Collections.Concurrent;
using System.IO;
using System.Reflection;
using System.Xml;

namespace MS.Quality.Component.Utility
{
    /// <summary>
    /// 日志帮助类
    /// </summary>
    public class Log4NetUtility
    {
        private static readonly ConcurrentDictionary<Type, ILog> _loggers = new ConcurrentDictionary<Type, ILog>();
        /// <summary>
        /// 获取记录器
        /// </summary>
        /// <param name="source"></param>
        /// <returns></returns>
        private static ILog GetLogger(Type source)
        {
            if (_loggers.ContainsKey(source))
            {
                return _loggers[source];
            }
            else
            {
                ILog logger = LogManager.GetLogger(source);
                SetLog4NetConfiguration();
                _loggers.TryAdd(source, logger);
                return logger;
            }
        }

        /// <summary>
        /// 调试信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        public static void Debug(object source, string message)
        {
            Debug(source.GetType(), message);
        }

        /// <summary>
        /// 调试信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        /// <param name="ps"></param>
        public static void Debug(object source, string message, params object[] ps)
        {
            Debug(source.GetType(), string.Format(message, ps));
        }

        /// <summary>
        /// 调试信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        public static void Debug(Type source, string message)
        {
            ILog logger = GetLogger(source);
            if (logger.IsDebugEnabled)
                logger.Debug(message);
        }
        /// <summary>
        /// 关键信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        public static void Info(object source, object message)
        {
            Info(source.GetType(), message);
        }

        /// <summary>
        /// 关键信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        public static void Info(Type source, object message)
        {
            ILog logger = GetLogger(source);
            if (logger.IsInfoEnabled)
                logger.Info(message);
        }

        /// <summary>
        /// 警告信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        public static void Warn(object source, object message)
        {
            Warn(source.GetType(), message);
        }

        /// <summary>
        /// 警告信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        public static void Warn(Type source, object message)
        {
            ILog logger = GetLogger(source);
            if (logger.IsWarnEnabled)
                logger.Warn(message);
        }

        /// <summary>
        /// 错误信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        public static void Error(object source, object message)
        {
            Error(source.GetType(), message);
        }

        /// <summary>
        /// 错误信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        public static void Error(Type source, object message)
        {
            ILog logger = GetLogger(source);
            if (logger.IsErrorEnabled)
                logger.Error(message);
        }

        /// <summary>
        /// 失败信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        public static void Fatal(object source, object message)
        {
            Fatal(source.GetType(), message);
        }

        /// <summary>
        /// 失败信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        public static void Fatal(Type source, object message)
        {
            ILog logger = GetLogger(source);
            if (logger.IsFatalEnabled)
                logger.Fatal(message);
        }

        /* Log a message object and exception */

        /// <summary>
        /// 调试信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        /// <param name="exception"></param>
        public static void Debug(object source, object message, Exception exception)
        {
            Debug(source.GetType(), message, exception);
        }

        /// <summary>
        /// 调试信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        /// <param name="exception"></param>
        public static void Debug(Type source, object message, Exception exception)
        {
            GetLogger(source).Debug(message, exception);
        }

        /// <summary>
        /// 关键信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        /// <param name="exception"></param>
        public static void Info(object source, object message, Exception exception)
        {
            Info(source.GetType(), message, exception);
        }

        /// <summary>
        /// 关键信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        /// <param name="exception"></param>
        public static void Info(Type source, object message, Exception exception)
        {
            GetLogger(source).Info(message, exception);
        }

        /// <summary>
        /// 警告信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        /// <param name="exception"></param>
        public static void Warn(object source, object message, Exception exception)
        {
            Warn(source.GetType(), message, exception);
        }

        /// <summary>
        /// 警告信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        /// <param name="exception"></param>
        public static void Warn(Type source, object message, Exception exception)
        {
            GetLogger(source).Warn(message, exception);
        }

        /// <summary>
        /// 错误信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        /// <param name="exception"></param>
        public static void Error(object source, object message, Exception exception)
        {
            Error(source.GetType(), message, exception);
        }

        /// <summary>
        /// 错误信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        /// <param name="exception"></param>
        public static void Error(Type source, object message, Exception exception)
        {
            GetLogger(source).Error(message, exception);
        }

        /// <summary>
        /// 失败信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        /// <param name="exception"></param>
        public static void Fatal(object source, object message, Exception exception)
        {
            Fatal(source.GetType(), message, exception);
        }

        /// <summary>
        /// 失败信息
        /// </summary>
        /// <param name="source"></param>
        /// <param name="message"></param>
        /// <param name="exception"></param>
        public static void Fatal(Type source, object message, Exception exception)
        {
            GetLogger(source).Fatal(message, exception);
        }
        private static void SetLog4NetConfiguration()
        {
            var repo = LogManager.CreateRepository(
                Assembly.GetEntryAssembly(), typeof(log4net.Repository.Hierarchy.Hierarchy));
            log4net.Config.XmlConfigurator.Configure(repo, new FileInfo("Log4Net.config"));
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <!--添加自定义节点：log4net  type：解析类名，程序集名(log4net.dll)-->
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
  </configSections>

  <log4net>
    <!--定义输出到文件中-->
    <appender name="Log4Net_INFO" type="log4net.Appender.RollingFileAppender">
      <!--定义文件存放位置-->
      <file value="Log/Info/"/>
      <!--是否追加到文件,默认为true，通常无需设置-->
      <appendToFile value="true"/>
      <RollingStyle value="Date"/>
      <!--日期的格式，每月一个文件夹，每天换一个文件记录，如不设置则永远只记录一天的日志，需设置-->
      <DatePattern value="yyyy-MM/yyyy-MM-dd&quot;.log&quot;" />
      <!--日志文件名是否为静态-->
      <StaticLogFileName value="false"/>
      <!--多线程时采用最小锁定-->
      <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
      <!--布局（向用户显示最后经过格式化的输出信息）-->
      <layout type="log4net.Layout.PatternLayout">
        <!--
           %m(message):输出的日志消息，如ILog.Debug(…)输出的一条消息 
           %n(new line):换行 
           %d(datetime):输出当前语句运行的时刻 
           %r(run time):输出程序从运行到执行到当前语句时消耗的毫秒数 
           %t(thread id):当前语句所在的线程ID 
           %p(priority): 日志的当前优先级别，即DEBUG、INFO、WARN…等 
           %c(class):当前日志对象的名称，例如：
           %L：输出语句所在的行号 
           %F：输出语句所在的文件名 
           %-数字：表示该项的最小长度，如果不够，则用空格填充
          -->
        <Header value="[Header]&#13;&#10;"/>
        <Footer value="[Footer]&#13;&#10;"/>
        <!--正文-->
        <ConversionPattern value="%date ThreadID:[%thread] Level：%-5level Logger：%logger property:[%property{NDC}] %nMessage：%message%newline"  />
      </layout>
      <filter type="log4net.Filter.LevelRangeFilter">
        <levelMin value="Debug" />
        <levelMax value="Warn" />
      </filter>
    </appender>

    <appender name="Log4Net_ERROR" type="log4net.Appender.RollingFileAppender">
      <file value="Log/Error/"/>
      <appendToFile value="true"/>
      <RollingStyle value="Date"/>
      <DatePattern value="yyyy-MM/yyyy-MM-dd&quot;.log&quot;" />
      <StaticLogFileName value="false"/>
      <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
      <layout type="log4net.Layout.PatternLayout">
        <Header value="[Header]&#13;&#10;"/>
        <Footer value="[Footer]&#13;&#10;"/>
        <!--正文-->
        <ConversionPattern value="%date ThreadID:[%thread] Level：%-5level Logger：%logger property:[%property{NDC}] %nMessage：%message%newline"  />
      </layout>
      <filter type="log4net.Filter.LevelRangeFilter">
        <levelMin value="ERROR" />
        <levelMax value="FATAL" />
      </filter>
    </appender>

    <root>
      <level value="ALL"/>
      <appender-ref ref="Log4Net_INFO" />
      <appender-ref ref="Log4Net_ERROR" />
    </root>

  </log4net>

</configuration>

　　 Log4NetUtility.Info(this, "guid:" + guid);

　　2，.NET Core

　　a，使用Log4NetUtility.cs帮助类库，使用方式同.NET Framework，Log4Net.config同上

　　b，使用依赖注入方式

<?xml version="1.0" encoding="utf-8"?>
<log4net>
  <!--定义输出到文件中-->
  <appender name="Log4Net_INFO" type="log4net.Appender.RollingFileAppender">
    <!--定义文件存放位置-->
    <file value="Log/Info/"/>
    <!--是否追加到文件,默认为true，通常无需设置-->
    <appendToFile value="true"/>
    <RollingStyle value="Date"/>
    <!--日期的格式，每月一个文件夹，每天换一个文件记录，如不设置则永远只记录一天的日志，需设置-->
    <DatePattern value="yyyy-MM/yyyy-MM-dd&quot;.log&quot;" />
    <!--日志文件名是否为静态-->
    <StaticLogFileName value="false"/>
    <!--多线程时采用最小锁定-->
    <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
    <!--布局（向用户显示最后经过格式化的输出信息）-->
    <layout type="log4net.Layout.PatternLayout">
      <!--
           %m(message):输出的日志消息，如ILog.Debug(…)输出的一条消息 
           %n(new line):换行 
           %d(datetime):输出当前语句运行的时刻 
           %r(run time):输出程序从运行到执行到当前语句时消耗的毫秒数 
           %t(thread id):当前语句所在的线程ID 
           %p(priority): 日志的当前优先级别，即DEBUG、INFO、WARN…等 
           %c(class):当前日志对象的名称，例如：
           %L：输出语句所在的行号 
           %F：输出语句所在的文件名 
           %-数字：表示该项的最小长度，如果不够，则用空格填充
          -->
      <Header value="[Header]&#13;&#10;"/>
      <Footer value="[Footer]&#13;&#10;"/>
      <!--正文-->
      <ConversionPattern value="%date ThreadID:[%thread] Level：%-5level Logger：%logger property:[%property{NDC}] %nMessage：%message%newline"  />
    </layout>
    <filter type="log4net.Filter.LevelRangeFilter">
      <levelMin value="Debug" />
      <levelMax value="Warn" />
    </filter>
  </appender>

  <appender name="Log4Net_ERROR" type="log4net.Appender.RollingFileAppender">
    <file value="Log/Error/"/>
    <appendToFile value="true"/>
    <RollingStyle value="Date"/>
    <DatePattern value="yyyy-MM/yyyy-MM-dd&quot;.log&quot;" />
    <StaticLogFileName value="false"/>
    <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
    <layout type="log4net.Layout.PatternLayout">
      <Header value="[Header]&#13;&#10;"/>
      <Footer value="[Footer]&#13;&#10;"/>
      <!--正文-->
      <ConversionPattern value="%date ThreadID:[%thread] Level：%-5level Logger：%logger property:[%property{NDC}] %nMessage：%message%newline"  />
    </layout>
    <filter type="log4net.Filter.LevelRangeFilter">
      <levelMin value="ERROR" />
      <levelMax value="FATAL" />
    </filter>
  </appender>

  <root>
    <level value="ALL"/>
    <appender-ref ref="Log4Net_INFO" />
    <appender-ref ref="Log4Net_ERROR" />
  </root>

</log4net>

　　Programe.cs：

.ConfigureLogging(logging =>
{
    logging.AddFilter("System", LogLevel.Warning);//过滤系统日志
    logging.AddFilter("Microsoft", LogLevel.Warning);
    logging.AddLog4Net("Log4Net.config");//Log4Net.config文件路径
})

 日志Level过滤也可以在appconfigs.json中进行配置：

{
  "Logging": {
    "LogLevel": { // No provider, LogLevel applies to all the enabled providers.
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Warning"
    },
    "Debug": { // Debug provider.
      "LogLevel": {
        "Default": "Information" // Overrides preceding LogLevel:Default setting.
      }
    },
    "Console": {
      "IncludeScopes": true,
      "LogLevel": {
        "Microsoft.AspNetCore.Mvc.Razor.Internal": "Warning",
        "Microsoft.AspNetCore.Mvc.Razor.Razor": "Debug",
        "Microsoft.AspNetCore.Mvc.Razor": "Error",
        "Default": "Information"
      }
    },
    "EventSource": {
      "LogLevel": {
        "Microsoft": "Information"
      }
    },
    "EventLog": {
      "LogLevel": {
        "Microsoft": "Information"
      }
    },
    "AzureAppServicesFile": {
      "IncludeScopes": true,
      "LogLevel": {
        "Default": "Warning"
      }
    },
    "AzureAppServicesBlob": {
      "IncludeScopes": true,
      "LogLevel": {
        "Microsoft": "Information"
      }
    },
    "ApplicationInsights": {
      "LogLevel": {
        "Default": "Information"
      }
    }
  }
}