.NET 云原生架构师训练营（模块二 基础巩固 依赖注入）--学习笔记

namespace HelloApi
{
    public class Program
    {
        public static void Main(string[] args)
        {
            var host = CreateHostBuilder(args).Build();

            Console.WriteLine("Server started");

            // 依赖查找
            var helloService = host.Services.GetRequiredService<IHelloService>();
            helloService.Hello();

            host.Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureServices((ctx,services)=>
                {
                    // 依赖注入
                    // 任何时候获取到的都是一个新的实例
                    services.AddTransient<IHelloService, HelloService>();
                })
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                });
    }
}

namespace HelloApi.Services
{
    public interface IHelloService
    {
         void Hello();
    }
}

namespace HelloApi.Services
{
    public class HelloService : IHelloService
    {
        public void Hello()
        {
            Console.WriteLine("hello dotnet core");
        }
    }
}

// 依赖注入
// 任何时候获取到的都是一个新的实例
services.AddTransient<IHelloService, HelloService>();
// 每个 scope 都有一个实例
services.AddScoped<IHelloService, HelloService>();
// 单例，整个应用程序的生命周期只有一个实例
services.AddSingleton<IHelloService, HelloService>();

private string _id;

public HelloService()
{
    _id = Guid.NewGuid().ToString();
}

// 依赖查找
var helloService1 = host.Services.GetRequiredService<IHelloService>();
helloService1.Hello();

var helloService2 = host.Services.GetRequiredService<IHelloService>();
helloService2.Hello();

Server started
hello dotnet core: cc77ee85-3806-4c29-b693-8da8bcf40498
hello dotnet core: 3306bebc-2340-4645-82e7-0e15fac0e9c7

.ConfigureServices((ctx,services)=>
{
    // 依赖注入
    // 单例，整个应用程序的生命周期只有一个实例
    services.AddSingleton<IHelloService, HelloService>();
})

Server started
hello dotnet core: 35aa7646-e2bd-4d44-8f15-cd6aca3b0215
hello dotnet core: 35aa7646-e2bd-4d44-8f15-cd6aca3b0215

using (var scope = host.Services.CreateScope())
{
    // 依赖查找
    var helloService1 = scope.ServiceProvider.GetRequiredService<IHelloService>();
    helloService1.Hello();

    var helloService2 = scope.ServiceProvider.GetRequiredService<IHelloService>();
    helloService2.Hello();
}

.ConfigureServices((ctx,services)=>
{
    // 依赖注入
    // 每个 scope 都有一个实例
    services.AddScoped<IHelloService, HelloService>();
})

Server started
hello dotnet core: abf083e2-7914-43b9-8e7f-540381a05b37
hello dotnet core: abf083e2-7914-43b9-8e7f-540381a05b37