webapi使用log4net

log4net加载配置文件有3种方式：

1、在项目Properties》Assemblyinfo.cs文件中加assembly attribute

（1）在项目配置文件中：app.config/web.config

[assembly:log4net.Config.XmlConfigurator(Watch=true)]

（2）单独的配置文件：log4net.config

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

2、显示调用

（1）在项目配置文件中：app.config/web.config

log4net.Config.XmlConfigurator.Configure();

（2）单独的配置文件：log4net.config

FileInfo fileInfo = new FileInfo(AppDomain.CurrentDomain.BaseDirectory+"\\log4net.config");
log4net.Config.XmlConfigurator.Configure(fileInfo);

3、app.config中配置

<appSetting>
<add key="log4net.Config" value="log4net.config"/>
<add key="log4net.Config.Watch"  value="True"/>
</appSetting>