var factory = ServiceProvider.GetRequiredService<ILoggerFactory>();
 var logger1 = factory.CreateLogger(typeof(HomeController).FullName); //CreateLogger
 var logger2 = factory.CreateLogger<HomeController>(); //CreateLogger

 logger1.Log(LogLevel.Information, 1, null, null, null); // 日志记录
 logger1.LogInformation("123"); // 扩展方法
 logger1.LogError("123"); // 扩展方法

public interface ILoggerFactory
{
 //日志最小记录级别
 LogLevel MinimumLevel { get; set; }

 //创建日志记录实例
 ILogger CreateLogger(string categoryName); //一般是根据功能模块或类名进行分类

 void AddProvider(ILoggerProvider provider); // 添加日志记录provider（如第三方实现）
}

public enum LogLevel
{
 Debug = 1,
 Verbose = 2,
 Information = 3,
 Warning = 4,
 Error = 5,
 Critical = 6,
}

public static ILoggerFactory AddConsole(this ILoggerFactory factory)
{
 factory.AddProvider(new ConsoleLoggerProvider((category, logLevel) => logLevel >= LogLevel.Information));
 return factory;
}

public interface ILoggerProvider
{
 ILogger CreateLogger(string name); //创建给定类别的ILgger实例
}

public interface ILogger
{
 //支持大多数日志记录的通用方法，其它访问通过扩展方法进行完善
 void Log(LogLevel logLevel, int eventId, object state, Exception exception, Func<object, Exception, string> formatter);

 //判断是否可以记录给定的日志级别
 bool IsEnabled(LogLevel logLevel);

 //开启一个逻辑操作作用域
 IDisposable BeginScopeImpl(object state);
}

loggerfactory.AddConsole()
loggerfactory.AddNLog(new NLog.LogFactory())
loggerfactory.AddSerilog(new LoggerConfiguration())
var testSwitch = new SourceSwitch("TestSwitch", "Level will be set to warning for this test");
factory.AddTraceSource(testSwitch, new ConsoleTraceListener());

public static void LogInformation(this ILogger logger, string message)
public static void LogInformation(this ILogger logger, int eventId, string message)
public static void LogInformation(this ILogger logger, string format, params object[] args)
public static void LogInformation(this ILogger logger, int eventId, string format, params object[] args)
public static void LogInformation(this ILogger logger, ILogValues state, Exception error = null)
public static void LogInformation(this ILogger logger, int eventId, ILogValues state, Exception error = null)

// 其它Debug、Verbose、Warning、Error、Critical也都遵循LogXXXX()规则.

public static void LogWarning(this ILogger logger, string message, Exception error)
public static void LogWarning(this ILogger logger, int eventId, string message, Exception error)