How to integrate and use log4net logging plug-in in vs2019 class library

log4net brief introduction

log4net Currently, it is a very popular log plug-in .

log4net Kuo is Apache log4j In the framework of Microsoft .NET Implementation of the platform , It is a tool to help programmers output log information to various targets ( Console 、 file 、 Database etc. ) Tools for .

log4net yes Apache Software foundation Apache Logging Services Part of the project .Apache The logging service project is committed to providing cross language logging services for program debugging and auditing .

VS2019 Use in log4net, Three steps ：

step 1： Integrate log4net Plug in to the project

open VS2019, New class library project ：

In the project , open NulGet Program management pack , Search and install log4net：

step2： Create a new calling class MyLogHelper.

Create a new class in the project , The code is as follows ：

using System;

// Here is the configuration log4net The location of the configuration file , Is the key , Most of it is because there is no pair configured here, resulting in no log Output 
//ConfigFile  Express log4net Location of profile .
[assembly: log4net.Config.XmlConfigurator(ConfigFile = "mylog4net.xml", ConfigFileExtension = "config", Watch = true)]
namespace MyLog4netHelper
{
   public class MyLogHelper
    {
        //GetLogger Express log4net In profile logger In the label name attribute , Be consistent here   Otherwise none log Output 
        private static readonly log4net.ILog Log = log4net.LogManager.GetLogger("RollingLogFileAppender");
        //  private static readonly log4net.ILog logError = log4net.LogManager.GetLogger("logerror");
      
        /// <summary>
        ///  Record Info journal 
        /// </summary>
        /// <param name="msg"></param>
        /// <param name="ex"></param>
        public static void Info(string msg)
        {          
            if (Log.IsInfoEnabled)
            {
                Log.Info(msg);
            }
        }

        /// <summary>
        ///  Record Fatal journal 
        /// </summary>
        /// <param name="msg"></param>
        /// <param name="ex"></param>
        public static void Fatal(string msg)
        {
            if (Log.IsFatalEnabled)
            {
                Log.Fatal(msg);
            }
        }

        /// <summary>
        ///  Record Debug journal 
        /// </summary>
        /// <param name="msg"></param>
        /// <param name="ex"></param>
        public static void Debug(string msg)
        {
            if (Log.IsDebugEnabled)
            {
                Log.Debug(msg);
            }
        }
        /// <summary>
        ///  Record Warn journal 
        /// </summary>
        /// <param name="msg"></param>
        /// <param name="ex"></param>
        public static void Warn(string msg)
        {
            if (Log.IsWarnEnabled)
            {
                Log.Warn(msg);
            }
        }


        /// <summary>
        ///  Record Error journal 
        /// </summary>
        /// <param name="errorMsg"></param>
        /// <param name="ex"></param>
        public static void Error(string info, Exception ex = null)
        {
            if (!string.IsNullOrEmpty(info) && ex == null)
            {
                Log.ErrorFormat("【 Additional information 】 : {0}<br>", new object[] { info });
            }
            else if (!string.IsNullOrEmpty(info) && ex != null)
            {
                string errorMsg = BeautyErrorMsg(ex);
                Log.ErrorFormat("【 Additional information 】 : {0}<br>{1}", new object[] { info, errorMsg });
            }
            else if (string.IsNullOrEmpty(info) && ex != null)
            {
                string errorMsg = BeautyErrorMsg(ex);
                Log.Error(errorMsg);
            }
        }

        /// <summary>
        ///  Beautify error messages 
        /// </summary>
        /// <param name="ex"> abnormal </param>
        /// <returns> error message </returns>
        private static string BeautyErrorMsg(Exception ex)
        {
            string errorMsg = string.Format("【 Exception types 】：{0} <br>【 Abnormal information 】：{1} <br>【 Stack call 】：{2}", new object[] { ex.GetType().Name, ex.Message, ex.StackTrace });
            errorMsg = errorMsg.Replace("\r\n", "<br>");
            errorMsg = errorMsg.Replace(" Location ", "<strong style=\"color:red\"> Location </strong>");
            return errorMsg;
        }
    }
}

step3 Configure and use ：

First look at the configuration file ：mylog4net.xml

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

<log4net>
    <root>
  
    </root>
  <logger name="RollingLogFileAppender">
    <level value="ALL" />
   <!--<appender-ref ref="RollingFileDebug" />--> 
    <appender-ref ref="RollingFileInfo" />
    <appender-ref ref="RollingFileWarn" />
    <appender-ref ref="RollingFileError" />
    <appender-ref ref="RollingFileFatal" />
    <appender-ref ref="Console" />
  </logger>
  <appender name="Console" type="log4net.Appender.ConsoleAppender">
    <layout type="log4net.Layout.PatternLayout">
      <!-- Pattern to output the caller's file name and line number -->
      <conversionPattern value="%5level [%thread] (%file:%line) - %message%newline" />
    </layout>
  </appender>
    <appender name="RollingFileDebug" type="log4net.Appender.RollingFileAppender">
      <param name="File" value="MyLog/Debug/"/>
      <param name="AppendToFile" value="true"/>
      <param name="MaxSizeRollBackups" value="100"/>
      <param name="StaticLogFileName" value="false"/>
      <param name="DatePattern" value="yyyyMMdd&quot;.htm&quot;"/>
      <param name="RollingStyle" value="Date"/>
      <param name="MaxFileSize" value="10240" />
      <layout type="log4net.Layout.PatternLayout">
        <!--<conversionPattern value="[%date{HH:mm:ss fff}] %-5level - %message%newline" />-->
        <param name="ConversionPattern" value="&lt;HR COLOR=red&gt;%n【 Log time 】：%d [%t] &lt;BR&gt;%n【 The level of logging 】：%-5p &lt;BR&gt;%n【 Exception class 】：%c [%x] &lt;BR&gt;%n%m &lt;BR&gt;%n &lt;HR Size=1&gt;"  />
      </layout>
      <lockingmodel type="log4net.appender.fileappender+minimallock" />
      <filter type="log4net.Filter.LevelRangeFilter">
        <param name="LevelMin" value="Debug" />
        <param name="LevelMax" value="Debug" />
      </filter>
    </appender>
    <appender name="RollingFileInfo" type="log4net.Appender.RollingFileAppender">
      <param name="File" value="MyLog/Info/"/>
      <param name="AppendToFile" value="true"/>
      <param name="MaxSizeRollBackups" value="100"/>
      <param name="MaxFileSize" value="10240" />
      <param name="StaticLogFileName" value="false"/>
      <param name="DatePattern" value="yyyyMMdd&quot;.htm&quot;"/>
      <param name="RollingStyle" value="Date"/>
      <layout type="log4net.Layout.PatternLayout">
        <param name="ConversionPattern" value="&lt;HR COLOR=blue&gt;%n Log time ：%d [%t] &lt;BR&gt;%n The level of logging ：%-5p &lt;BR&gt;%n Japan   Records   class ：%c [%x] &lt;BR&gt;%n%m &lt;BR&gt;%n &lt;HR Size=1&gt;"  />
      </layout>
      <lockingmodel type="log4net.appender.fileappender+minimallock" />
      <filter type="log4net.Filter.LevelRangeFilter">
        <param name="LevelMin" value="INFO" />
        <param name="LevelMax" value="INFO" />
      </filter>
    </appender>
    <appender name="RollingFileWarn" type="log4net.Appender.RollingFileAppender">
      <param name="File" value="MyLog/Warn/"/>
      <param name="AppendToFile" value="true"/>
      <param name="MaxSizeRollBackups" value="100"/>
      <param name="MaxFileSize" value="10240" />
      <param name="StaticLogFileName" value="false"/>
      <param name="DatePattern" value="yyyyMMdd&quot;.htm&quot;"/>
      <param name="RollingStyle" value="Date"/>
      <layout type="log4net.Layout.PatternLayout">
        <param name="ConversionPattern" value="&lt;HR COLOR=yellow&gt;%n Log time ：%d [%t] &lt;BR&gt;%n The level of logging ：%-5p &lt;BR&gt;%n Japan   Records   class ：%c [%x] &lt;BR&gt;%n%m &lt;BR&gt;%n &lt;HR Size=1&gt;"  />
      </layout>
      <lockingmodel type="log4net.appender.fileappender+minimallock" />
      <filter type="log4net.Filter.LevelRangeFilter">
        <param name="LevelMin" value="WARN" />
        <param name="LevelMax" value="WARN" />
      </filter>
    </appender>
    <appender name="RollingFileError" type="log4net.Appender.RollingFileAppender">
      <param name="File" value="MyLog/Error/"/>
      <param name="AppendToFile" value="true"/>
      <param name="MaxSizeRollBackups" value="10"/>
      <param name="MaxFileSize" value="10240" />
      <param name="StaticLogFileName" value="false"/>
      <param name="DatePattern" value="yyyyMMdd&quot;.htm&quot;"/>
      <param name="RollingStyle" value="Date"/>
      <layout type="log4net.Layout.PatternLayout">
        <param name="ConversionPattern" value="&lt;HR COLOR=red&gt;%n Log time ：%d [%t] &lt;BR&gt;%n The level of logging ：%-5p &lt;BR&gt;%n Japan   Records   class ：%c [%x] &lt;BR&gt;%n%m &lt;BR&gt;%n &lt;HR Size=1&gt;"  />
      </layout>
      <lockingmodel type="log4net.appender.fileappender+minimallock" />
      <filter type="log4net.Filter.LevelRangeFilter">
        <param name="LevelMin" value="ERROR" />
        <param name="LevelMax" value="ERROR" />
      </filter>
    </appender>
    <appender name="RollingFileFatal" type="log4net.Appender.RollingFileAppender">
      <param name="File" value="MyLog/Fatal/"/>
      <param name="AppendToFile" value="true"/>
      <param name="MaxSizeRollBackups" value="10"/>
      <param name="StaticLogFileName" value="false"/>
      <param name="DatePattern" value="yyyyMMdd&quot;.htm&quot;"/>
          <param name="MaxFileSize" value="10240" />
      <param name="RollingStyle" value="Date"/>
      <layout type="log4net.Layout.PatternLayout">
        <param name="ConversionPattern" value="&lt;HR COLOR=red&gt;%n Log time ：%d [%t] &lt;BR&gt;%n The level of logging ：%-5p &lt;BR&gt;%n Japan   Records   class ：%c [%x] &lt;BR&gt;%n%m &lt;BR&gt;%n &lt;HR Size=1&gt;"  />
      </layout>
      <lockingmodel type="log4net.appender.fileappender+minimallock" />
      <filter type="log4net.Filter.LevelRangeFilter">
        <param name="LevelMin" value="FATAL" />
        <param name="LevelMax" value="FATAL" />
      </filter>
    </appender>
    
   
  </log4net>
</configuration>

The configuration file is placed in the root directory of the program that calls the class library .

It's easy to use ：

 MyLogHelper.Info("msg"）;
 MyLogHelper.Fatal("msg"）;
 MyLogHelper.Debug("msg"）;
 MyLogHelper.Error("msg"）;

According to the configuration in the configuration file , Different types of log files will be written to the corresponding configuration file path , In specific use, you can customize the format you want in the configuration file according to your needs .

Last

Project structure ：

matters needing attention ：MyLogHelper The configuration file path written earlier in the class [assembly: log4net.Config.XmlConfigurator(ConfigFile = "mylog4net.xml", ConfigFileExtension = "config", Watch = true)] Don't get the corresponding file name wrong , To ensure that the configuration file can be read correctly .

log4net Plug ins are thread safe , Everything has been done inside the plug-in , Don't worry about locking in the process of use .（ It is said that the lower version is not thread safe , Try to use the latest version ）