log4net.Config

startup.cs 里修改静态文件的地址：

app.UseStaticFiles(new StaticFileOptions()
{
FileProvider =new PhysicalFileProvider(Path.Combine(Directory.GetCurrentDirectory(),@"wwwroot"));
};

log4net

1.添加引用
2.startup.cs configure 添加
public void Configure(IApplicationBuilder app, IWebHostEnvironment env, ILoggerFactory loggerFactory)
{
loggerFactory.AddLog4Net();
}
3. controller 添加
private readonly ILoggerFactory _loggerFactory;
public FirstController(ILoggerFactory loggerFactory)
{
this._loggerFactory = loggerFactory;
}

this._loggerFactory.CreateLogger<FirstController>().LogWarning("This is FirstController-Index 1");

log4net.Config:

<?xml version="1.0" encoding="utf-8"?>
<log4net>
<!-- Define some output appenders -->
<appender name="rollingAppender" type="log4net.Appender.RollingFileAppender">
<file value="loglog.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>
<root>
<priority value="ALL"/>
<level value="ALL"/>
<appender-ref ref="rollingAppender" />
</root>
</log4net>