log4net根据命名空间创建日志

1.首先安装log4net安装包

在解决方案资源管理器中右键单击依赖项->管理nuget程序包->浏览 搜索log4net选择后面的安装（本人安装的是2.0.8版本）在弹出来的接受许可证中选择我接受，安装完成后依赖项下面的nuget就会如下所示

在Startup类中添加如下代码

public static ILoggerRepository repository { get; set; }
        public IConfiguration Configuration { get; }
        public Startup(IConfiguration configuration)
        {
            //加载log4net日志配置文件
            repository = LogManager.CreateRepository("NETCoreRepository");
            Configuration = configuration;
        }

新增ReadParamAppender类

public class ReadParamAppender : log4net.Appender.AppenderSkeleton
    {
        private string _file;
        public string File
        {
            get { return this._file; }
            set { _file = value; }
        }

        private int _maxSizeRollBackups;
        public int MaxSizeRollBackups
        {
            get { return this._maxSizeRollBackups; }
            set { _maxSizeRollBackups = value; }
        }

        private bool _appendToFile = true;
        public bool AppendToFile
        {
            get { return this._appendToFile; }
            set { _appendToFile = value; }
        }

        private string _maximumFileSize;
        public string MaximumFileSize
        {
            get { return this._maximumFileSize; }
            set { _maximumFileSize = value; }
        }

        private string _layoutPattern;
        public string LayoutPattern
        {
            get { return this._layoutPattern; }
            set { _layoutPattern = value; }
        }

        private string _datePattern;
        public string DatePattern
        {
            get { return this._datePattern; }
            set { _datePattern = value; }
        }

        private string _level;
        public string Level
        {
            get { return this._level; }
            set { _level = value; }
        }

        protected override void Append(log4net.Core.LoggingEvent loggingEvent)
        {
        }
    }

添加CustomRollingFileLogger类

[assembly: log4net.Config.XmlConfigurator(Watch = true)]
namespace TimingStart.Models
{
    public class CustomRollingFileLogger
    {
        private static readonly ConcurrentDictionary<string, ILog> loggerContainer = new ConcurrentDictionary<string, ILog>();

        private static readonly Dictionary<string, ReadParamAppender> appenderContainer = new Dictionary<string, ReadParamAppender>();
        private static object lockObj = new object();

        //默认配置  
        private const int MAX_SIZE_ROLL_BACKUPS = 20;
        private const string LAYOUT_PATTERN = "%d [%t] %-5p %c  - %m%n";
        private const string DATE_PATTERN = "yyyyMMdd\".txt\"";
        private const string MAXIMUM_FILE_SIZE = "256MB";
        private const string LEVEL = "debug";

        //读取配置文件并缓存  
        static CustomRollingFileLogger()
        {
            IAppender[] appenders = LogManager.GetRepository(Startup.repository.Name).GetAppenders();
            for (int i = 0; i < appenders.Length; i++)
            {
                if (appenders[i] is ReadParamAppender)
                {
                    ReadParamAppender appender = (ReadParamAppender)appenders[i];
                    if (appender.MaxSizeRollBackups == 0)
                    {
                        appender.MaxSizeRollBackups = MAX_SIZE_ROLL_BACKUPS;
                    }
                    if (appender.Layout != null && appender.Layout is log4net.Layout.PatternLayout)
                    {
                        appender.LayoutPattern = ((log4net.Layout.PatternLayout)appender.Layout).ConversionPattern;
                    }
                    if (string.IsNullOrEmpty(appender.LayoutPattern))
                    {
                        appender.LayoutPattern = LAYOUT_PATTERN;
                    }
                    if (string.IsNullOrEmpty(appender.DatePattern))
                    {
                        appender.DatePattern = DATE_PATTERN;
                    }
                    if (string.IsNullOrEmpty(appender.MaximumFileSize))
                    {
                        appender.MaximumFileSize = MAXIMUM_FILE_SIZE;
                    }
                    if (string.IsNullOrEmpty(appender.Level))
                    {
                        appender.Level = LEVEL;
                    }
                    lock (lockObj)
                    {
                        appenderContainer[appenders[i].Name] = appender;
                    }
                }
            }
        }

        public static ILog GetCustomLogger(string loggerName, string category = null, bool additivity = false)//loggerName:文件名，category：目录名
        {
            return loggerContainer.GetOrAdd(loggerName, delegate (string name)
            {
                RollingFileAppender newAppender = null;
                ReadParamAppender appender = null;
                if (appenderContainer.ContainsKey(loggerName))
                {
                    appender = appenderContainer[loggerName];
                    newAppender = GetNewFileApender(loggerName, string.IsNullOrEmpty(appender.File) ? GetFile(category, loggerName) : appender.File, appender.MaxSizeRollBackups,
                        appender.AppendToFile, true, appender.MaximumFileSize, RollingFileAppender.RollingMode.Composite, appender.DatePattern, appender.LayoutPattern);
                }
                else
                {
                    newAppender = GetNewFileApender(loggerName, GetFile(category, loggerName), MAX_SIZE_ROLL_BACKUPS, true, true, MAXIMUM_FILE_SIZE, RollingFileAppender.RollingMode.Composite,
                        DATE_PATTERN, LAYOUT_PATTERN);
                }
                log4net.Repository.Hierarchy.Hierarchy repository = (log4net.Repository.Hierarchy.Hierarchy)LogManager.GetRepository(Startup.repository.Name);
                Logger logger = repository.LoggerFactory.CreateLogger(repository, loggerName);
                logger.Hierarchy = repository;
                logger.Parent = repository.Root;
                logger.Level = GetLoggerLevel(appender == null ? LEVEL : appender.Level);
                logger.Additivity = additivity;
                logger.AddAppender(newAppender);
                logger.Repository.Configured = true;
                return new LogImpl(logger);
            });
        }

        //如果没有指定文件路径则在运行路径下建立 Log\{loggerName}.txt  
        private static string GetFile(string category, string loggerName)
        {
            if (string.IsNullOrEmpty(category))
            {
                return string.Format(@"Log\{0}.txt", loggerName);
            }
            else
            {
                return string.Format(@"Log\{0}\{1}.txt", category, loggerName);
            }
        }

        private static Level GetLoggerLevel(string level)
        {
            if (!string.IsNullOrEmpty(level))
            {
                switch (level.ToLower().Trim())
                {
                    case "debug":
                        return Level.Debug;

                    case "info":
                        return Level.Info;

                    case "warn":
                        return Level.Warn;

                    case "error":
                        return Level.Error;

                    case "fatal":
                        return Level.Fatal;
                }
            }
            return Level.Debug;
        }

        private static RollingFileAppender GetNewFileApender(string appenderName, string file, int maxSizeRollBackups, bool appendToFile = true, bool staticLogFileName = false, string maximumFileSize = "5MB", RollingFileAppender.RollingMode rollingMode = RollingFileAppender.RollingMode.Composite, string datePattern = "yyyyMMdd\".txt\"", string layoutPattern = "%d [%t] %-5p %c  - %m%n")
        {
            RollingFileAppender appender = new RollingFileAppender
            {
                LockingModel = new FileAppender.MinimalLock(),
                Name = appenderName,
                File = file,
                AppendToFile = appendToFile,
                MaxSizeRollBackups = maxSizeRollBackups,
                MaximumFileSize = maximumFileSize,
                StaticLogFileName = staticLogFileName,
                RollingStyle = rollingMode,
                DatePattern = datePattern,
                Encoding = System.Text.UTF8Encoding.UTF8
            };
            PatternLayout layout = new PatternLayout(layoutPattern);
            appender.Layout = layout;
            layout.ActivateOptions();
            appender.ActivateOptions();
            return appender;
        }
    }
}

利用以下代码默认在Log文件夹内生成日志文件tizhi.txt

public static ILog log = CustomRollingFileLogger.GetCustomLogger("rizhi", "");
log.Info("index页面");

详细请查看原博客：https://blog.youkuaiyun.com/autfish/article/details/51462922