一.环境变量
系统启动时,会读取环境变量 ASPNETCORE_ENVIRONMENT ,并将该变量的值存储在 IHostingEnvironment.EnvironmentName 字段中.如:
新建一个 WebAPI 项目,修改 Configure 方法:
???????public void Configure(IApplicationBuilder app, IHostingEnvironment env) ???????{ ???????????...... ???????????{ ???????????????app.Run(async context => ???????????????{ ???????????????????context.Response.ContentType = "text/plain;charset=utf-8";//没有这句话,中文会出现乱码. ???????????????????await context.Response.WriteAsync($"当前环境 : {env.EnvironmentName}"); ???????????????}); ???????????} ???????????...... ???????}ASPNETCORE_ENVIRONMENT 可以设置为任意值,但是 ASP.NET Core 框架只支持 3 个值:
Development
Staging
Production
如果没有设置该变量的值,则默认 Production
那么问题来了,在哪里设置呢?
方法一 : launchSettings.json
打开上例创建的 WebAPI 项目的 launchSettings.json 文件:
{ ?"$schema": "http://json.schemastore.org/launchsettings.json", ?"iisSettings": { ???"windowsAuthentication": false, ????"anonymousAuthentication": true, ????"iisExpress": { ?????"applicationUrl": "http://localhost:53476", ?????"sslPort": 44307 ???} ?}, ?"profiles": { ???//部署到IIS时,会读取该节点的设置. ???"IIS Express": { ?????"commandName": "IISExpress", ?????"launchBrowser": true, ?????"launchUrl": "api/values", ?????"environmentVariables": { ???????//"ASPNETCORE_ENVIRONMENT": "Development" ???????"ASPNETCORE_ENVIRONMENT": "Production" //我们修改为 "Production" 看效果 ?????} ???}, ???//在控制台启动时,会读取该节点的设置 ???"EnvironmentDemo1": { ?????"commandName": "Project", ?????"launchBrowser": true, ?????"launchUrl": "api/values", ?????"applicationUrl": "https://localhost:5001;http://localhost:5000", ?????"environmentVariables": { ???????"ASPNETCORE_ENVIRONMENT": "Staging" //我们修改为 "Staging" 看效果 ?????} ???} ?}}IIS下运行效果:
控制台运行效果:
二.基于环境的 Startup 类
当 ASP.NET Core 应用启动时,会在 Program 类中通过 Startup 类启动应用.
ASP.NET Core 提供了基于不同环境选择不同的 Startup 类的方法.但是类名有个约定,只能这样命名:
Startup{EnvironmentName}
EnvironmentName 为当前环境.
示例:
???/// <summary> ???/// 开发环境启动类 ???/// </summary> ???public class StartupDevelopment ???{ ???????public void ConfigureServices(IServiceCollection services){} ???????public void Configure(IApplicationBuilder app, IHostingEnvironment env){} ???} ???/// <summary> ???/// 模拟环境启动类 ???/// </summary> ???public class StartupStaging ???{ ???????public void ConfigureServices(IServiceCollection services){} ???????public void Configure(IApplicationBuilder app, IHostingEnvironment env){} ???} ???/// <summary> ???/// 生产环境启动类 ???/// </summary> ???public class StartupProduction ???{ ???????public void ConfigureServices(IServiceCollection services){} ???????public void Configure(IApplicationBuilder app, IHostingEnvironment env){} ???}要让系统根据当前环境选择上述3个启动类中的一个,还需要修改调用方法.
默认的调用方法是这样的:
???public class Program ???{ ???????public static void Main(string[] args) ???????{ ???????????CreateWebHostBuilder(args).Build().Run(); ???????} ???????public static IWebHostBuilder CreateWebHostBuilder(string[] args) => WebHost.CreateDefaultBuilder(args).UseStartup<Startup>(); ???}需要修改成:
???????public static IWebHostBuilder CreateWebHostBuilder(string[] args) ???????{ ???????????var assemblyName = typeof(Startup).GetTypeInfo().Assembly.FullName; ???????????return WebHost.CreateDefaultBuilder(args).UseStartup(assemblyName); ???????}二.基于环境的 ConfigureServices 方法和 Configure 方法
上代码一目了然:
???????public void ConfigureStaging(IApplicationBuilder app, IHostingEnvironment env) ???????{ ???????} ???????public void ConfigureStagingServices(IServiceCollection services) ???????{ ???????}ASP.NET Core 2.2 基础知识(五) 环境
原文地址：https://www.cnblogs.com/lonelyxmas/p/10230839.html