本文介紹.net6.0中引入的minimal hosting model和如何將.net6.0以前的版本轉(zhuǎn)換成6.0

1. minimal hosting model長啥樣

在入門.net的過程中，我發(fā)現(xiàn)program.cs里面的寫法有些是長這樣的：

var builder = WebApplication.CreateBuilder(args);

builder.Configuration.AddIniFile("appsettings.ini");

var app = builder.Build();

有些是長這樣的

public class Program
{
    public static void Main(string[] args)
    {
        CreateHostBuilder(args).Build().Run();
    }

    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.UseStartup<Startup>();
            });
}

后者看起來更正式一點(diǎn)，所以我以為第一種是鬧著玩的，真正的項(xiàng)目是不會這么用的，但是當(dāng)我仔細(xì)看官方文檔的時候發(fā)現(xiàn)，其實(shí)是不同版本的aps.net的寫法，第一種是net6.0的，第二種是.net5.0的。

2. 為何引入minimal hosting model

這個結(jié)果真是出乎我意料，所以我就去查了一下為啥要改成鬧著玩的方式（其實(shí)這種方式由自己的名字：minimal hosting model），然后官方的回答是：簡單
對比一下可以發(fā)現(xiàn)確實(shí)簡單了很多，以下是兩個等同的配置，在.net5.0的時候是：

public class Program
{
    public static void Main(string[] args)
    {
        CreateHostBuilder(args).Build().Run();
    }

    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.UseStartup<Startup>();
            });
}

和

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddRazorPages();
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        else
        {
            app.UseExceptionHandler("/Error");
            // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
            app.UseHsts();
        }

        app.UseHttpsRedirection();
        app.UseStaticFiles();

        app.UseRouting();

        app.UseAuthorization();

        app.MapRazorPages();
    }
}

很長，但是有用的就那么幾句，再來看看.net6.0的：

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddRazorPages();

var app = builder.Build();

if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Error");
    // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
    app.UseHsts();
}

app.UseHttpsRedirection();
app.UseStaticFiles();

app.UseRouting();

app.UseAuthorization();

app.MapRazorPages();

app.Run();

剛好把有用的幾句摘抄出來了，所以新的版本確實(shí)更簡單了

3.如何轉(zhuǎn)換成minimal hosting model

重要的就兩個：
IServiceCollection
另一個是IApplicationBuilder 和IWebHostEnvironment
轉(zhuǎn)成6.0就是
builder.Services
和app和app.Environment

參考
https://gist.github.com/davidfowl/0e0372c3c1d895c3ce195ba983b1e03d#custom-dependency-injection-container文章來源地址http://www.zghlxwxcb.cn/news/detail-402818.html

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