CPU：i5-8265U 硬盘：固态硬盘 测试结果：每秒写入文件大约1万到3万条日志，每条日志的字符串长度是140多个字符
支持多线程并发，支持多进程并发，支持按文件大小分隔日志文件
LogUtil.cs代码：
using System; using System.Collections.Concurrent; using System.Collections.Generic; using System.IO; using System.Linq; using System.Reflection; using System.Text; using System.Text.RegularExpressions; using System.Threading; using System.Threading.Tasks; namespace Utils { /// <summary> /// 写日志类 /// </summary> public class LogUtil { #region 字段 private static string _path = null; private static Mutex _mutex = new Mutex(false, "LogUtil.Mutex.180740C3B1C44D428683D35F84F97E22"); private static ConcurrentDictionary<string, int> _dictIndex = new ConcurrentDictionary<string, int>(); private static ConcurrentDictionary<string, long> _dictSize = new ConcurrentDictionary<string, long>(); private static ConcurrentDictionary<string, FileStream> _dictStream = new ConcurrentDictionary<string, FileStream>(); private static ConcurrentDictionary<string, StreamWriter> _dictWriter = new ConcurrentDictionary<string, StreamWriter>(); private static ConcurrentDictionary<string, string> _dictPathFolders = new ConcurrentDictionary<string, string>(); private static TaskSchedulerEx _scheduler = new TaskSchedulerEx(2, 2); private static int _fileSize = 10 * 1024 * 1024; //日志分隔文件大小 #endregion #region 写文件 /// <summary> /// 写文件 /// </summary> private static void WriteFile(LogType logType, string log, string path) { try { FileStream fs = null; StreamWriter sw = null; if (!(_dictStream.TryGetValue(logType.ToString() + path, out fs) && _dictWriter.TryGetValue(logType.ToString() + path, out sw))) { foreach (string key in _dictWriter.Keys) { if (key.StartsWith(logType.ToString())) { StreamWriter item; _dictWriter.TryRemove(key, out item); item.Close(); } } foreach (string key in _dictStream.Keys) { if (key.StartsWith(logType.ToString())) { FileStream item; _dictStream.TryRemove(key, out item); item.Close(); } } if (!Directory.Exists(Path.GetDirectoryName(path))) { Directory.CreateDirectory(Path.GetDirectoryName(path)); } fs = new FileStream(path, FileMode.Append, FileAccess.Write, FileShare.ReadWrite); sw = new StreamWriter(fs); _dictWriter.TryAdd(logType.ToString() + path, sw); _dictStream.TryAdd(logType.ToString() + path, fs); } fs.Seek(0, SeekOrigin.End); sw.WriteLine(log); sw.Flush(); fs.Flush(); } catch (Exception ex) { string str = ex.Message; } } #endregion #region 生成日志文件路径 /// <summary> /// 生成日志文件路径 /// </summary> private static string CreateLogPath(LogType logType, string log) { try { if (_path == null) { UriBuilder uri = new UriBuilder(Assembly.GetExecutingAssembly().CodeBase); _path = Path.GetDirectoryName(Uri.UnescapeDataString(uri.Path)); } string pathFolder = Path.Combine(_path, "Log\\" + logType.ToString() + "\\"); if (!_dictPathFolders.ContainsKey(pathFolder)) { if (!Directory.Exists(Path.GetDirectoryName(pathFolder))) { Directory.CreateDirectory(Path.GetDirectoryName(pathFolder)); } _dictPathFolders.TryAdd(pathFolder, pathFolder); } int currentIndex; long size; string strNow = DateTime.Now.ToString("yyyyMMdd"); string strKey = pathFolder + strNow; if (!(_dictIndex.TryGetValue(strKey, out currentIndex) && _dictSize.TryGetValue(strKey, out size))) { _dictIndex.Clear(); _dictSize.Clear(); GetIndexAndSize(pathFolder, strNow, out currentIndex, out size); if (size >= _fileSize) currentIndex++; _dictIndex.TryAdd(strKey, currentIndex); _dictSize.TryAdd(strKey, size); } int index = _dictIndex[strKey]; string logPath = Path.Combine(pathFolder, strNow + (index == 1 ? "" : "_" + index.ToString()) + ".txt"); _dictSize[strKey] += Encoding.UTF8.GetByteCount(log); if (_dictSize[strKey] > _fileSize) { _dictIndex[strKey]++; _dictSize[strKey] = 0; } return logPath; } catch (Exception ex) { string str = ex.Message; return null; } } #endregion #region 拼接日志内容 /// <summary> /// 拼接日志内容 /// </summary> private static string CreateLogString(LogType logType, string log) { return string.Format(@"{0} {1} {2}", DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff"), ("[" + logType.ToString() + "]").PadRight(7, ' '), log); } #endregion #region 获取初始Index和Size /// <summary> /// 获取初始Index和Size /// </summary> private static void GetIndexAndSize(string pathFolder, string strNow, out int index, out long size) { index = 1; size = 0; Regex regex = new Regex(strNow + "_*(\\d*).txt"); string[] fileArr = Directory.GetFiles(pathFolder); string currentFile = null; foreach (string file in fileArr) { Match match = regex.Match(file); if (match.Success) { string str = match.Groups[1].Value; if (!string.IsNullOrWhiteSpace(str)) { int temp = Convert.ToInt32(str); if (temp > index) { index = temp; currentFile = file; } } else { index = 1; currentFile = file; } } } if (currentFile != null) { FileInfo fileInfo = new FileInfo(currentFile); size = fileInfo.Length; } } #endregion #region 写调试日志 /// <summary> /// 写调试日志 /// </summary> public static Task Debug(string log) { return Task.Factory.StartNew(() => { try { _mutex.WaitOne(); log = CreateLogString(LogType.Debug, log); string path = CreateLogPath(LogType.Debug, log); WriteFile(LogType.Debug, log, path); } catch (Exception ex) { string str = ex.Message; } finally { _mutex.ReleaseMutex(); } }, CancellationToken.None, TaskCreationOptions.None, _scheduler); } #endregion #region 写错误日志 public static Task Error(Exception ex, string log = null) { return Error(string.IsNullOrEmpty(log) ? ex.Message + "\r\n" + ex.StackTrace : (log + "：") + ex.Message + "\r\n" + ex.StackTrace); } /// <summary> /// 写错误日志 /// </summary> public static Task Error(string log) { return Task.Factory.StartNew(() => { try { _mutex.WaitOne(); log = CreateLogString(LogType.Error, log); string path = CreateLogPath(LogType.Error, log); WriteFile(LogType.Error, log, path); } catch (Exception ex) { string str = ex.Message; } finally { _mutex.ReleaseMutex(); } }, CancellationToken.None, TaskCreationOptions.None, _scheduler); } #endregion #region 写操作日志 /// <summary> /// 写操作日志 /// </summary> public static Task Log(string log) { return Task.Factory.StartNew(() => { try { _mutex.WaitOne(); log = CreateLogString(LogType.Info, log); string path = CreateLogPath(LogType.Info, log); WriteFile(LogType.Info, log, path); } catch (Exception ex) { string str = ex.Message; } finally { _mutex.ReleaseMutex(); } }, CancellationToken.None, TaskCreationOptions.None, _scheduler); } #endregion } #region 日志类型 /// <summary> /// 日志类型 /// </summary> public enum LogType { Debug, Info, Error } #endregion }