ASP.NET Core 使用Log4Net写文本日志和数据库日志

1，先安装依赖

2，在项目目录新建Log4Net.config配置文件，必须要安装System.Data.SqlClient，不然日志存不进去数据库

<?xml version="1.0" encoding="utf-8"?>
<log4net>
	<!-- Define some output appenders -->
	<appender name="rollingAppender" type="log4net.Appender.RollingFileAppender">
		<file value="log4\log.txt" />
		<!--追加日志内容-->
		<appendToFile value="true" />

		<!--防止多线程时不能写Log,官方说线程非安全-->
		<lockingModel type="log4net.Appender.FileAppender+MinimalLock" />

		<!--可以为:Once|Size|Date|Composite-->
		<!--Composite为Size和Date的组合-->
		<rollingStyle value="Composite" />

		<!--当备份文件时,为文件名加的后缀-->
		<datePattern value="yyyyMMdd.TXT" />

		<!--日志最大个数,都是最新的-->
		<!--rollingStyle节点为Size时,只能有value个日志-->
		<!--rollingStyle节点为Composite时,每天有value个日志-->
		<maxSizeRollBackups value="20" />

		<!--可用的单位:KB|MB|GB-->
		<maximumFileSize value="3MB" />

		<!--置为true,当前最新日志文件名永远为file节中的名字-->
		<staticLogFileName value="true" />

		<!--输出级别在INFO和ERROR之间的日志-->
		<filter type="log4net.Filter.LevelRangeFilter">
			<param name="LevelMin" value="ALL" />
			<param name="LevelMax" value="FATAL" />
		</filter>
		<layout type="log4net.Layout.PatternLayout">
			<conversionPattern value="%date [%thread] %-5level %logger - %message%newline"/>
		</layout>
	</appender>

	<!--SqlServer形式-->
	<!--log4net日志配置：http://logging.apache.org/log4net/release/config-examples.html -->
	<appender name="AdoNetAppender_SqlServer" type="log4net.Appender.AdoNetAppender">
		<!--日志缓存写入条数 设置为0时只要有一条就立刻写到数据库-->
		<bufferSize value="0" />
		<connectionType value="System.Data.SqlClient.SqlConnection,System.Data.SqlClient, Version=4.6.1.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
		<connectionString value="Data Source=;Initial Catalog=;Persist Security Info=True;User ID=;Password=" />
		<commandText value="INSERT INTO Log4Net ([Date],[Thread],[Level],[Logger],[Message],[Exception]) VALUES (@log_date, @thread, @log_level, @logger, @message, @exception)" />
		<parameter>
			<parameterName value="@log_date" />
			<dbType value="DateTime" />
			<layout type="log4net.Layout.RawTimeStampLayout" />
		</parameter>
		<parameter>
			<parameterName value="@thread" />
			<dbType value="String" />
			<size value="255" />
			<layout type="log4net.Layout.PatternLayout">
				<conversionPattern value="%thread" />
			</layout>
		</parameter>
		<parameter>
			<parameterName value="@log_level" />
			<dbType value="String" />
			<size value="50" />
			<layout type="log4net.Layout.PatternLayout">
				<conversionPattern value="%level" />
			</layout>
		</parameter>
		<parameter>
			<parameterName value="@logger" />
			<dbType value="String" />
			<size value="255" />
			<layout type="log4net.Layout.PatternLayout">
				<conversionPattern value="%logger" />
			</layout>
		</parameter>
		<parameter>
			<parameterName value="@message" />
			<dbType value="String" />
			<size value="4000" />
			<layout type="log4net.Layout.PatternLayout">
				<conversionPattern value="%message" />
			</layout>
		</parameter>
		<parameter>
			<parameterName value="@exception" />
			<dbType value="String" />
			<size value="2000" />
			<layout type="log4net.Layout.ExceptionLayout" />
		</parameter>
	</appender>

	<root>

		<!--控制级别，由低到高: ALL|DEBUG|INFO|WARN|ERROR|FATAL|OFF-->
		<!--OFF:0-->
		<!--FATAL:FATAL-->
		<!--ERROR: ERROR,FATAL-->
		<!--WARN: WARN,ERROR,FATAL-->
		<!--INFO: INFO,WARN,ERROR,FATAL-->
		<!--DEBUG: INFO,WARN,ERROR,FATAL-->
		<!--ALL: DEBUG,INFO,WARN,ERROR,FATAL-->
		<priority value="ALL"/>

		<level value="INFO"/>
		<appender-ref ref="rollingAppender" />
		<appender-ref ref="AdoNetAppender_SqlServer" />
	</root>
</log4net>

3，在Program文件注册