项目需求

asp.net core 读取log目录下的.log文件，.log文件的内容如下：

xxx.log

------------------------------------------begin---------------------------------
写入时间:2018-09-11 17:01:48
userid=1000
golds=10
-------------------------------------------end---------------------------------

一个 begin end 为一组，同一个.log文件里 userid 相同的，取写入时间最大一组值，所需结果如下：

UserID Golds RecordDate
1001 20 2018/9/11 17:10:48
1000 20 2018/9/11 17:11:48
1003 30 2018/9/11 17:12:48
1002 10 2018/9/11 18:01:48
1001 20 2018/9/12 17:10:48
1000 30 2018/9/12 17:12:48
1002 10 2018/9/12 18:01:48

项目结构

Snai.File.FileOperation Asp.net core 2.0 网站

项目实现

新建Snai.File解决方案，在解决方案下新建一个名Snai.File.FileOperation Asp.net core 2.0 空网站

把log日志文件拷备到项目下

修改Startup类的ConfigureServices()方法，注册访问本地文件所需的服务，到时在中间件中通过构造函数注入添加到中间件，这样就可以在一个地方控制文件的访问路径（也就是应用程序启动的时候）

public void ConfigureServices(IServiceCollection services){　　services.AddSingleton<IFileProvider>(new PhysicalFileProvider(Directory.GetCurrentDirectory()));}

新建 Middleware 文件夹，在 Middleware下新建 Entity 文件夹，新建 UserGolds.cs 类，用来保存读取的日志内容，代码如下

namespace Snai.File.FileOperation.Middleware.Entity{ public class UserGolds { public UserGolds() { RecordDate = new DateTime(1970, 01, 01); UserID = 0; Golds = 0; } public DateTime RecordDate { get; set; } public int UserID { get; set; } public int Golds { get; set; } }}

在 Middleware 下新建 FileProviderMiddleware.cs 中间件类，用于读取 log 下所有日志文件内容，并整理成所需的内容格式，代码如下

namespace Snai.File.FileOperation.Middleware{ public class FileProviderMiddleware { private readonly RequestDelegate _next; private readonly IFileProvider _fileProvider; public FileProviderMiddleware(RequestDelegate next, IFileProvider fileProvider) { _next = next; _fileProvider = fileProvider; } public async Task Invoke(HttpContext context) { var output = new StringBuilder(""); //ResolveDirectory(output, "", ""); ResolveFileInfo(output, "log", ".log"); await context.Response.WriteAsync(output.ToString()); } //读取目录下所有文件内容 private void ResolveFileInfo(StringBuilder output, string path, string suffix) { output.AppendLine("UserID Golds RecordDate"); IDirectoryContents dir = _fileProvider.GetDirectoryContents(path); foreach (IFileInfo item in dir) { if (item.IsDirectory) { ResolveFileInfo(output, item.PhysicalPath.Substring(Directory.GetCurrentDirectory().Length), suffix); } else { if (item.Name.Contains(suffix)) { var userList = new List<UserGolds>(); var user = new UserGolds(); IFileInfo file = _fileProvider.GetFileInfo(path + "\\" + item.Name); using (var stream = file.CreateReadStream()) { using (var reader = new StreamReader(stream)) { string content = reader.ReadLine(); while (content != null) { if (content.Contains("begin")) { user = new UserGolds(); } if (content.Contains("写入时间")) { DateTime recordDate; string strRecordDate = content.Substring(content.IndexOf(":") + 1).Trim(); if (DateTime.TryParse(strRecordDate, out recordDate)) { user.RecordDate = recordDate; } } if (content.Contains("userid")) { int userID; string strUserID = content.Substring(content.LastIndexOf("=") + 1).Trim(); if (int.TryParse(strUserID, out userID)) { user.UserID = userID; } } if (content.Contains("golds")) { int golds; string strGolds = content.Substring(content.LastIndexOf("=") + 1).Trim(); if (int.TryParse(strGolds, out golds)) { user.Golds = golds; } } if (content.Contains("end")) { var userMax = userList.FirstOrDefault(u => u.UserID == user.UserID); if (userMax == null || userMax.UserID <= 0) { userList.Add(user); } else if (userMax.RecordDate < user.RecordDate) { userList.Remove(userMax); userList.Add(user); } } content = reader.ReadLine(); } } } if (userList != null && userList.Count > 0) { foreach (var golds in userList.OrderBy(u => u.RecordDate)) { output.AppendLine(golds.UserID.ToString() + " " + golds.Golds + " " + golds.RecordDate); } output.AppendLine(""); } } } } } //读取目录下所有文件名 private void ResolveDirectory(StringBuilder output, string path, string prefix) { IDirectoryContents dir = _fileProvider.GetDirectoryContents(path); foreach (IFileInfo item in dir) { if (item.IsDirectory) { output.AppendLine(prefix + "[" + item.Name + "]"); ResolveDirectory(output, item.PhysicalPath.Substring(Directory.GetCurrentDirectory().Length), prefix + " "); } else { output.AppendLine(path + prefix + item.Name); } } } } public static class UseFileProviderExtensions { public static IApplicationBuilder UseFileProvider(this IApplicationBuilder app) { return app.UseMiddleware<FileProviderMiddleware>(); } }}

上面有两个方法 ResolveFileInfo()和ResolveDirectory()

ResolveFileInfo() 读取目录下所有文件内容，也就是需求所用的方法

ResolveDirectory() 读取目录下所有文件名，是输出目录下所有目录和文件名，不是需求所需但也可以用

修改Startup类的Configure()方法，在app管道中使用文件中间件服务

public void Configure(IApplicationBuilder app, IHostingEnvironment env){　　if (env.IsDevelopment())　　{　　　　app.UseDeveloperExceptionPage();　　}　　app.UseFileProvider();　　　　app.Run(async (context) =>　　{　　　　await context.Response.WriteAsync("Hello World!");　　});}

到此所有代码都已编写完成

启动运行项目，得到所需结果，页面结果如下

源码访问地址：https://github.com/Liu-Alan/Snai.File

总结

以上所述是小编给大家介绍的.net core 读取本地指定目录下的文件的相关知识，希望对大家有所帮助，如果大家有任何疑问欢迎给我留言，小编会及时回复大家的！