Log4net is in Net core usage

log4net Use , Log information can be output to various terminals （ text file 、 database 、windows Log etc. ）, The implementation process is mainly about how to configure the configuration files of various output modes ：

1. install log4net package

If you need to output to the database , Corresponding import package

Be careful ： If in .net core Use in , And in Program.cs Register configuration in , The second package mentioned above must be introduced

2. New configuration file log4net.config

Of course, the name of the configuration file can be customized , The attribute is “ Always copy ”. Just register right . The specific configuration method is available on the official website Apache log4net – Apache log4net: Config Examples - Apache log4net, The code description will also be posted at the end of this article .

3. call log4net

（1） Normal call method , Applicable to .Net Core and .Net FrameWork All items  

  // establish logger, The name can be defined at will 
            ILoggerRepository repository = LogManager.CreateRepository("logNETCoreRepository");
            // Appoint log4net Configuration file for , It's yours log4net The file of 
            XmlConfigurator.Configure(repository, new FileInfo("log4net.config"));
            // Statement log object , Designated to use logger And searcher name , The name of the retriever corresponds to... In the log template logger, It can be an assembly name or customized 
            //var log = log4net.LogManager.GetLogger(repository.Name, "logNETCoreRepository1");
            // Statement log object , Designated to use logger And searcher name , The name of the retriever corresponds to... In the log template logger, It can be an assembly name or customized , Here is the full name of the current method class + Method name 
            var log = log4net.LogManager.GetLogger(repository.Name, System.Reflection.MethodBase.GetCurrentMethod().DeclaringType.FullName+"."+System.Reflection.MethodBase.GetCurrentMethod().Name);
            // Write to the log 
            log.Info("addlog");
            // Write warning message 
            log.Warn("Warn");

You can also integrate this paragraph into a help class to use .

（2） stay .Net Core MVC Can be used by dependency injection ：

First, in the Program.cs Of CreateHostBuilder Configure in method Log4net:

 public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureLogging(logger => logger.AddLog4Net("log4net.config"))//log4net The configuration file 
                .ConfigureAppConfiguration((hostingContext, config) =>
                {
                    config.Sources.Clear();
                })
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                });

Then in the controller or model Middle dependency injection ILogger：

    public class HomeController : Controller
    {
        private readonly ILogger<HomeController> _logger;
        private readonly MyModel _mm;
        private readonly IConfiguration _configuration;

        public HomeController(ILogger<HomeController> logger, MyModel mm, IConfiguration Configuration)
        {
            _logger = logger;
            _mm = mm;
            _configuration = Configuration;
            _logger.LogInformation("HomeController Constructed ...");
        }

        public IActionResult Index()
        {
            _logger.LogInformation("Home Index  To be accessed ...");
            string ret = _mm.test();

            string temp = _configuration["ccc"];

            return Content($"{temp}----{ret}");
        }

    }

（3） Of course. .Net Framework You can use , stay Properties Of AssemblyInfo.cs Add the following code in , To specify log4net Configuration file for

[assembly: log4net.Config.XmlConfigurator(ConfigFile = "log4net.config", ConfigFileExtension = "config", Watch = true)]

This requires two more steps , One is in log4net.config Lieutenant general root Replace node with logger node

	<logger name="loginfo">
		<level value="ALL"/>
		<appender-ref ref="rollingAppender" />
	</logger>

Finally, when calling, call ：

var log=log4net.LogManager.GetLogger("loginfo");//loginfo This is the... In the previous step logger name
log.Info("addlog")

4. Configuration information , Include in append text file ,sqlite database ,mysql Database and windows In the log .

<?xml version="1.0" encoding="utf-8"?>
<log4net debug="true">// Open the debug 
	<!-- Define some output appenders -->
	<appender name="rollingAppender" type="log4net.Appender.RollingFileAppender">
		<file value="log\log.txt" />

		<!-- Add log content -->
		<appendToFile value="true" />

		<!-- Prevent multithreading when unable to write Log, Officials say threads are not safe -->
		<lockingModel type="log4net.Appender.FileAppender+MinimalLock" />

		<!-- It can be for :Once|Size|Date|Composite-->
		<!--Composite by Size and Date The combination of -->
		<rollingStyle value="Composite" />

		<!-- When backing up files , Suffix to the file name -->
		<datePattern value="yyyyMMdd.txt" />

		<!-- Maximum number of logs , It's all the latest -->
		<!--rollingStyle The node is Size when , There can only be value A journal -->
		<!--rollingStyle The node is Composite when , Every day value A journal -->
		<maxSizeRollBackups value="3" />

		<!-- Available units :KB|MB|GB-->
		<maximumFileSize value="2KB" />

		<!-- Set as true, The current latest log file name is always file The name of the festival -->
		<staticLogFileName value="true" />

		<!-- Output level in INFO and ERROR Log between -->
		<filter type="log4net.Filter.LevelRangeFilter">
			<param name="LevelMin" value="INFO" />
			<param name="LevelMax" value="FATAL" />
		</filter>

		<layout type="log4net.Layout.PatternLayout">
			<conversionPattern value="%date [%thread] %-5level %logger - %message%newline"/>
		</layout>
	</appender>
	<!-- Write to sqlite database -->
	<appender name="AdoNetAppender" type="log4net.Appender.AdoNetAppender">
		<!-- The size of the buffer event , Set to less than or equal to 1 Value , No buffering will occur , Logging is performed synchronously , Otherwise, the event will be buffered -->
		<bufferSize value="1" />
		<!-- Database type -->
		<connectionType value="System.Data.SQLite.SQLiteConnection,System.Data.SQLite" />
		<!-- Database address -->
		<connectionString value="Data Source=~/log.db;Version=3;" />
		<!-- Write log statement -->
		<commandText value="INSERT INTO Log(Date, Level, Logger, Message) VALUES (@Date, @Level, @Logger, @Message)" />
		<parameter>
			<!-- Configuration fields -->
			<parameterName value="@Date" />
			<!-- Field data type -->
			<dbType value="DateTime" />
			<!-- Beijing time. -->
			<layout type="log4net.Layout.RawTimeStampLayout" />
		</parameter>
		<parameter>
			<parameterName value="@Level" />
			<dbType value="String" />
			<layout type="log4net.Layout.PatternLayout">
				<conversionPattern value="%level" />
			</layout>
		</parameter>
		<parameter>
			<parameterName value="@Logger" />
			<dbType value="String" />
			<layout type="log4net.Layout.PatternLayout">
				<conversionPattern value="%logger" />
			</layout>
		</parameter>
		<parameter>
			<parameterName value="@Message" />
			<dbType value="String" />
			<layout type="log4net.Layout.PatternLayout">
				<conversionPattern value="%message" />
			</layout>
		</parameter>
	</appender>
	<!-- Write to mysql database -->
	<appender name="MysqlAdoNetAppender" type="log4net.Appender.AdoNetAppender">
		<!-- The size of the buffer event , Set to less than or equal to 1 Value , No buffering will occur , Logging is performed synchronously , Otherwise, the event will be buffered -->
		<bufferSize value="1" />
		<!-- Database type -->
		<connectionType value="MySql.Data.MySqlClient.MySqlConnection,MySql.Data" />
		<!-- Database address -->
		<connectionString value="server=192.168.1.188;port=3306;database=enav;uid=root;pwd=root;" />
		<!-- Write log statement -->
		<commandText value="INSERT INTO lognet(`Date`, `Level`, `Logger`, `Message`) VALUES (@date, @level, @logger, @message)" />
		<parameter>
			<!-- Configuration fields -->
			<parameterName value="@date" />
			<!-- Field data type -->
			<dbType value="DateTime" />
			<!-- Beijing time. -->
			<layout type="log4net.Layout.RawTimeStampLayout" />
		</parameter>
		<parameter>
			<parameterName value="@level" />
			<dbType value="String" />
			<layout type="log4net.Layout.PatternLayout">
				<conversionPattern value="%level" />
			</layout>
		</parameter>
		<parameter>
			<parameterName value="@logger" />
			<dbType value="String" />
			<layout type="log4net.Layout.PatternLayout">
				<conversionPattern value="%logger" />
			</layout>
		</parameter>
		<parameter>
			<parameterName value="@message" />
			<dbType value="String" />
			<layout type="log4net.Layout.PatternLayout">
				<conversionPattern value="%message" />
			</layout>
		</parameter>
	</appender>
	<!-- Write to windows In the log -->
	<appender name="EventLogAppender" type="log4net.Appender.EventLogAppender" >
		<layout type="log4net.Layout.PatternLayout">
			<conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
		</layout>
	</appender>

	<!-- levels: OFF > FATAL > ERROR > WARN > INFO > DEBUG  > ALL -->

	<root>
		<priority value="ALL"/>
		<level value="ALL"/>
		<appender-ref ref="AdoNetAppender" />
		<appender-ref ref="MysqlAdoNetAppender" />
		<appender-ref ref="rollingAppender" />
		<appender-ref ref="EventLogAppender" />
	</root>
</log4net>

It's using MySql when , Found some versions in use Mysql Database nuget Packet time , Write failure , Has been an error , Just change the version , I don't know Mysql Some versions are right Log4net Compatibility .

There's also an important point , Turn on log4net Debugging is right here log4net Add in node debug="true" Just fine , You can print it on the console log4net Relevant debugging information .

End