（初识MVC Core）一、初识管道和生命周期

1.新建一个Mvc Core项目

注：刚开始依赖项是有黄色三角形，等待安装

2.打开Startup.cs，修改Configure

public void Configure(IApplicationBuilder app, IHostingEnvironment env,ILogger<Startup> logger)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.Run(async (context) =>
            {
                await context.Response.WriteAsync("Hello World!");
            });

            app.Use(async (context, next) =>
            {
                logger.LogInformation("M1 Start");
                await context.Response.WriteAsync("Hello World!");
                await next();
                logger.LogInformation("M1 End");
            });

            app.Run(async (context) =>
            {
                logger.LogInformation("M2 Start");
                await context.Response.WriteAsync("Another World!");
                logger.LogInformation("M2 End");
            });

        }