更新

LogStudy.WebApp/Controllers/LogController.cs

@@ -0,0 +1,54 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Logging;
+
+namespace LogStudy.WebApp.Controllers
+{
+    [Route("api/[controller]/[action]")]
+    [ApiController]
+    public class LogController : ControllerBase
+    {
+        private ILogger logger;
+        public LogController(ILogger<LogController> logger)
+        {
+            this.logger = logger;
+        }
+
+        [HttpGet]
+        [HttpPost]
+        public IActionResult Index()
+        {
+            logger.LogTrace("EventSource 提供程序");
+            logger.LogError(new EventId(222, "EWT测试"), "EWT错误{id}", 222);
+            logger.LogDebug("LogDebug");
+            logger.LogInformation("LogInformation");
+            logger.LogWarning("LogWarning");
+            logger.LogError("LogError");
+            logger.LogCritical("LogCritical");
+
+            return new JsonResult(new { Code=0, Message="日志记录成功" });
+        }
+
+        [HttpGet]
+        [HttpPost]
+        public IActionResult NoDI()
+        {
+            var  loggerFactory = new LoggerFactory().AddConsole();
+            var logger2 = loggerFactory.CreateLogger<LogController>();
+
+            logger2.LogTrace("LogTrace");
+            logger2.LogDebug("LogDebug");
+            logger2.LogInformation("LogInformation");
+            logger2.LogWarning("LogWarning");
+            logger2.LogError("LogError");
+            logger2.LogCritical("LogCritical");
+
+
+            return new JsonResult(new { Code = 0, Message = "日志记录成功" });
+        }
+    }
+}

LogStudy.WebApp/Controllers/ValuesController.cs

@@ -23,10 +23,6 @@ namespace LogStudy.WebApp.Controllers
         [HttpGet]
         public ActionResult<IEnumerable<string>> Get()
         {
-            _logger.LogCritical("我是测试");
-
-            _logger.LogDebug("我是Debug测试");
-
             return new string[] { "value1", "value2" };
         }
 

LogStudy.WebApp/LogStudy.WebApp.csproj

@@ -9,11 +9,15 @@
     <PackageReference Include="Microsoft.AspNetCore.App" />
     <PackageReference Include="Microsoft.AspNetCore.Razor.Design" Version="2.2.0" PrivateAssets="All" />
     <PackageReference Include="Microsoft.Extensions.Logging" Version="2.2.0" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="2.2.0" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Configuration" Version="2.2.0" />
     <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="2.2.0" />
     <PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="2.2.0" />
     <PackageReference Include="Microsoft.Extensions.Logging.EventLog" Version="2.2.0" />
     <PackageReference Include="Microsoft.Extensions.Logging.EventSource" Version="2.2.0" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Filter" Version="1.1.2" />
     <PackageReference Include="Microsoft.Extensions.Logging.TraceSource" Version="2.2.0" />
+    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="2.2.4" />
   </ItemGroup>
 
 </Project>

LogStudy.WebApp/Program.cs

@@ -6,7 +6,10 @@ using System.Threading.Tasks;
 using Microsoft.AspNetCore;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Logging.Debug;
 
 namespace LogStudy.WebApp
 {
@@ -14,23 +17,65 @@ namespace LogStudy.WebApp
     {
         public static void Main(string[] args)
         {
-            CreateWebHostBuilder(args).Build().Run();
+           var host = CreateWebHostBuilder(args).Build();
+
+           //启动检查：使用日志
+           var logger = host.Services.GetRequiredService<ILogger<Program>>();
+           logger.LogInformation("检查数据库连接");
+           logger.LogDebug(new EventId(1000,"事件名"),"检查缓存{id}",222);
+            //少提供一个参数
+           logger.LogInformation("1001","检查MQ{id}{name}",3333);
+           
+           host.Run();
         }
 
-        public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
-            WebHost.CreateDefaultBuilder(args)
-                .ConfigureLogging((hostbuildContext, logBuild) => {
+        public static IWebHostBuilder CreateWebHostBuilder(string[] args)
+        {
+            var webBuilder = WebHost.CreateDefaultBuilder(args)
+                //配置日志
+                 .ConfigureLogging((hostbuildContext, logBuild) =>
+                 {
+                     //CreateDefaultBuilder 默认注册了日志组件：
+                     //使用appsettings.环境变量.json 的Logging配置节
+                     //默认添加了以下提供程序：Console、 Debug、EventSource
+                     //详情可以查看源代码
+
+                     //本方法ConfigureLogging，重新配置日志
+                     //配置信息
                      var config = hostbuildContext.Configuration;
+                     //环境变量
                      var ev = hostbuildContext.HostingEnvironment;
+                     //注入服务
+                     var service=logBuild.Services;
 
                      logBuild
+                         //自定义配置信息
+                         .AddConfiguration(config.GetSection("Logging"))
+                         //添加Console提供程序
                          .AddConsole()
+                         //添加Debug提供程序
                          .AddDebug()
+                         //添加EventLog提供程序
                          .AddEventLog()
+                         //添加EventSourceLogger提供程序:EWT
                          .AddEventSourceLogger()
+                         //添加TraceSource提供程序
                          .AddTraceSource("NetCoreDemo")
-                        .SetMinimumLevel(LogLevel.Information);
+                         //设置最小默认日志级别
+                         .SetMinimumLevel(LogLevel.Information)
+                         //添加筛选器：会覆盖上面配置信息
+                         .AddFilter("System", LogLevel.Debug) //不指定提供程序，则应用与全部
+                         .AddFilter<DebugLoggerProvider>("Microsoft", LogLevel.Trace);//只作用于指定的提供程序 DebugLoggerProvider
+
+                     //以下方式，可以使用第三方日志组件，如Nlog、Log4net等
+                     //.ClearProviders()
+                     //.AddProvider(null)
+
                  })
                  .UseStartup<Startup>();
+
+            return webBuilder;
+        }
+           
     }
 }

LogStudy.WebApp/Startup.cs

@@ -9,14 +9,34 @@ using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Logging.Configuration;
+using Microsoft.Extensions.Logging.Console;
+using System.IO;
 
 namespace LogStudy.WebApp
 {
+    /// <summary>
+    /// 使用日志：
+    /// 1、构造函数注入
+    /// 2、使用 LoggerFactory 来创建 ILogger
+    /// </summary>
     public class Startup
     {
-        public Startup(IConfiguration configuration)
+        /// <summary>
+        /// 构建函数注入
+        /// </summary>
+        private readonly ILogger _logger;
+
+        /// <summary>
+        /// 工厂方法创建
+        /// </summary>
+        private readonly ILogger _logger2;
+        public Startup(IConfiguration configuration,ILogger<Startup> logger)
         {
             Configuration = configuration;
+            _logger=logger;
+            _logger2=GetLoggerFromFactory("Startup");
         }
 
         public IConfiguration Configuration { get; }
@@ -24,7 +44,10 @@ namespace LogStudy.WebApp
         // This method gets called by the runtime. Use this method to add services to the container.
         public void ConfigureServices(IServiceCollection services)
         {
+            _logger.LogInformation("配置服务开始");
             services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
+
+            _logger2.LogInformation("配置服务结束");
         }
 
         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
@@ -37,5 +60,14 @@ namespace LogStudy.WebApp
 
             app.UseMvc();
         }
+
+        private ILogger GetLoggerFromFactory(string name)
+        {
+            var fac=new LoggerFactory();
+
+           var logger = fac.AddConsole().CreateLogger(name);
+
+           return logger;
+        } 
     }
 }

LogStudy.WebApp/appsettings.Development.json

@@ -2,8 +2,8 @@
   "Logging": {
     "LogLevel": {
       "Default": "Debug",
-      "System": "Information",
-      "Microsoft": "Information"
+      "System": "Debug",
+      "Microsoft": "Debug"
     }
   }
 }

LogStudy.WebApp/appsettings.json

@@ -1,7 +1,20 @@
 {
-  "Logging": {
+  "Logging": 
+  {
+    "LogLevel": 
+    {
+      "Default": "Information",
+      "System": "Information",
+      "Microsoft": "Information"
+    },
+    "Console":
+    {
+      "IncludeScopes": true,
       "LogLevel": {
-      "Default": "Warning"
+        "Default": "Debug",
+        "System": "Debug",
+        "Microsoft": "Debug"
+      }
     }
   },
   "AllowedHosts": "*"