.NET IoC 容器（三）Autofac

Autofac

Autofac 是一个用于 .NET 应用程序的依赖注入 (Dependency Injection, DI) 容器。它帮助开发人员管理对象的创建和生命周期，使得依赖项的注入更加灵活和可维护。以下是 Autofac 的主要功能和特性概述：

依赖注入 (Dependency Injection)

Autofac 允许你通过构造函数、属性或方法注入依赖项。这样，你可以轻松地将对象的依赖关系传递给需要它们的类，从而提高代码的可测试性和可维护性。

模块化设计 (Modular Design)

Autofac 支持模块化设计，可以将相关的依赖项注册逻辑分组到模块中。这使得大型应用程序的配置更加简洁和易于管理。

生命周期管理 (Lifecycle Management)

Autofac 提供多种对象生命周期管理方式，例如单例 (Singleton)、每次请求 (Instance Per Dependency)、每个生命周期范围 (Instance Per Lifetime Scope) 等，允许你精确控制对象的创建和销毁时机。

注册与解析 (Registration and Resolution)

Autofac 通过流畅的 API 提供了多种注册组件的方式。你可以注册类型、实例、工厂方法，甚至通过扫描程序集自动注册组件。此外，Autofac 的解析功能支持构造函数参数注入、命名参数注入等高级特性。

支持 AOP (Aspect-Oriented Programming)

Autofac 与 AOP 框架（如 Castle Windsor）集成，支持横切关注点（如日志记录、事务管理）的处理，从而使业务逻辑代码更加简洁。

集成支持

Autofac 与许多流行的 .NET 库和框架集成良好，包括 ASP.NET Core、WCF、Web API、MVC 等。通过这些集成，Autofac 可以轻松地管理 web 应用程序中的依赖项。

扩展性

Autofac 具有很高的扩展性，可以通过自定义注册源、生命周期、解析器等方式扩展其功能，以满足特定应用的需求。

Nuget 安装

实现DI

定义接口

internal interface IComputer
{
}

internal interface IKeyboard
{
}

internal interface IMouse
{
}

internal interface IPerson
{IComputer Computer { get; set; }IKeyboard Keyboard { get; set; }IMouse Mouse { get; set; }void Work();
}

定义实现类

internal class ConstructBase
{public ConstructBase() {Console.WriteLine($"{this.GetType().Name} - 被构造了");}
}

internal class LenovoComputer : ConstructBase, IComputer
{public LenovoComputer() : base() { }
}

internal class TogarKeyboard : ConstructBase, IKeyboard
{public TogarKeyboard() : base() { }
}

internal class LogitechMouse : ConstructBase, IMouse
{public LogitechMouse() : base() { }
}

internal class Programmer : ConstructBase, IPerson
{public IComputer Computer { get; set; }public IKeyboard Keyboard { get; set; }public IMouse Mouse { get; set; }public Programmer(IComputer computer, IKeyboard keyboard, IMouse mouse) : base(){Computer = computer;Keyboard = keyboard;Mouse = mouse;}public void Work(){Console.WriteLine("Programmers are building software...");}
}

依赖注入

var builder = new ContainerBuilder();
builder.RegisterType<LenovoComputer>().As<IComputer>();
builder.RegisterType<TogarKeyboard>().As<IKeyboard>();
builder.RegisterType<LogitechMouse>().As<IMouse>();
builder.RegisterType<Programmer>().As<IPerson>();
var container = builder.Build();
IPerson programmer = container.Resolve<IPerson>();
programmer.Work();

输出

Zhy.IoC.Autofac.LenovoComputer - 被构造了
Zhy.IoC.Autofac.TogarKeyboard - 被构造了
Zhy.IoC.Autofac.LogitechMouse - 被构造了
Zhy.IoC.Autofac.Programmer - 被构造了
Programmers are building software...

注入方式

构造函数注入 | 属性注入 | 方法注入

定义特性用来筛选属性注入

public class InjectPropertyAttribute : Attribute
{}

定义实现类

public class Gamer : ConstructBase, IPerson
{public IComputer Computer { get; set; }[InjectProperty]public IKeyboard Keyboard { get; set; }public IMouse Mouse { get; set; }public Gamer(IComputer computer) : base(){Computer = computer;}public void Inject(IMouse mouse){Mouse = mouse;}public void Work(){Console.WriteLine("The player is playing...");}
}

注入实现

// 注入顺序（与编码顺序无关）：构造函数注入 > 属性注入 > 方法注入
var builder = new ContainerBuilder();
builder.RegisterType<LenovoComputer>().As<IComputer>();
builder.RegisterType<TogarKeyboard>().As<IKeyboard>();
builder.RegisterType<LogitechMouse>().As<IMouse>();
builder.RegisterType<Gamer>()// 方法注入.OnActivating(e =>{IMouse mouse = e.Context.Resolve<IMouse>();e.Instance.Inject(mouse);})// 属性注入.PropertiesAutowired((g, o) => g.Name == "Keyboard")// 构造函数注入.UsingConstructor(typeof(IComputer)).As<IPerson>();
var container = builder.Build();
IPerson gamer = container.Resolve<IPerson>();
gamer.Work();

输出

Zhy.IoC.Autofac.LenovoComputer - 被构造了
Zhy.IoC.Autofac.Gamer - 被构造了
Zhy.IoC.Autofac.TogarKeyboard - 被构造了
Zhy.IoC.Autofac.LogitechMouse - 被构造了
The player is playing...

结果

注入顺序：构造函数注入 > 属性注入 > 方法注入

接口注册

重复注册

var builder = new ContainerBuilder();
builder.RegisterType<LenovoComputer>().As<IComputer>();
builder.RegisterType<TogarKeyboard>().As<IKeyboard>();
builder.RegisterType<LogitechMouse>().As<IMouse>();
builder.RegisterType<Programmer>().As<IPerson>();
builder.RegisterType<Gamer>()// 方法注入.OnActivating(e =>{IMouse mouse = e.Context.Resolve<IMouse>();e.Instance.Inject(mouse);})// 属性注入.PropertiesAutowired((g, o) => g.Name == "Keyboard")// 构造函数注入.UsingConstructor(typeof(IComputer)).As<IPerson>();
var container = builder.Build();
IPerson programmer = container.Resolve<IPerson>();
programmer.Work();

输出

Zhy.IoC.Autofac.LenovoComputer - 被构造了
Zhy.IoC.Autofac.Gamer - 被构造了
Zhy.IoC.Autofac.TogarKeyboard - 被构造了
Zhy.IoC.Autofac.LogitechMouse - 被构造了
The player is playing...

调换Gamer和Programmer的注册顺序：

var builder = new ContainerBuilder();
builder.RegisterType<LenovoComputer>().As<IComputer>();
builder.RegisterType<TogarKeyboard>().As<IKeyboard>();
builder.RegisterType<LogitechMouse>().As<IMouse>();
builder.RegisterType<Gamer>()// 方法注入.OnActivating(e =>{IMouse mouse = e.Context.Resolve<IMouse>();e.Instance.Inject(mouse);})// 属性注入.PropertiesAutowired((g, o) => g.Name == "Keyboard")// 构造函数注入.UsingConstructor(typeof(IComputer)).As<IPerson>();
builder.RegisterType<Programmer>().As<IPerson>();
var container = builder.Build();
IPerson programmer = container.Resolve<IPerson>();
programmer.Work();

输出

Zhy.IoC.Autofac.LenovoComputer - 被构造了
Zhy.IoC.Autofac.TogarKeyboard - 被构造了
Zhy.IoC.Autofac.LogitechMouse - 被构造了
Zhy.IoC.Autofac.Programmer - 被构造了
Programmers are building software...

结论

同一接口多次注册时，后注册的会覆盖前面注册的，若需要实现多重注册，需要指定名称

var builder = new ContainerBuilder();
builder.RegisterType<LenovoComputer>().As<IComputer>();
builder.RegisterType<TogarKeyboard>().As<IKeyboard>();
builder.RegisterType<LogitechMouse>().As<IMouse>();
builder.RegisterType<Gamer>()// 方法注入.OnActivating(e =>{IMouse mouse = e.Context.Resolve<IMouse>();e.Instance.Inject(mouse);})// 属性注入.PropertiesAutowired((g, o) => g.Name == "Keyboard")// 构造函数注入.UsingConstructor(typeof(IComputer)).Named<IPerson>("person");
builder.RegisterType<Programmer>().Named<IPerson>("programmer");
var container = builder.Build();
IPerson programmer = container.ResolveNamed<IPerson>("programmer");
IPerson person = container.ResolveNamed<IPerson>("person");
programmer.Work();
person.Work();

输出

Zhy.IoC.Autofac.LenovoComputer - 被构造了
Zhy.IoC.Autofac.TogarKeyboard - 被构造了
Zhy.IoC.Autofac.LogitechMouse - 被构造了
Zhy.IoC.Autofac.Programmer - 被构造了
Zhy.IoC.Autofac.LenovoComputer - 被构造了
Zhy.IoC.Autofac.Gamer - 被构造了
Zhy.IoC.Autofac.TogarKeyboard - 被构造了
Zhy.IoC.Autofac.LogitechMouse - 被构造了
Programmers are building software...
The player is playing...

指定参数注册

修改接口

internal interface IMouse
{string Type { get; set; }
}

修改实现类

internal class LogitechMouse : ConstructBase, IMouse
{public LogitechMouse() : base() { }public LogitechMouse(string type) : base(){Type = type;}public string Type { get; set; }
}

注入

var builder = new ContainerBuilder();
builder.RegisterType<LogitechMouse>().WithParameter("type","502").As<IMouse>();
var container = builder.Build();
IMouse mouse = container.Resolve<IMouse>();
Console.WriteLine("mouse type: " + mouse.Type);

输出

Zhy.IoC.Autofac.LogitechMouse - 被构造了
mouse type: 502

生命周期

Instance Per Dependency（默认） 每次请求组件时都会创建一个新的实例。这是默认的生命周期管理模式。

builder.RegisterType<MyService>().As<IMyService>();

Singleton 在整个容器生命周期内，只有一个实例。

builder.RegisterType<MyService>().As<IMyService>().SingleInstance();

Instance Per Lifetime Scope 在每个生命周期范围内，共享一个实例。每个生命周期范围都会创建一个新的实例，但在该范围内共享该实例。

builder.RegisterType<MyService>().As<IMyService>().InstancePerLifetimeScope();

Instance Per Matching Lifetime Scope 在特定的生命周期范围内共享实例，需要指定标记。

builder.RegisterType<MyService>().As<IMyService>().InstancePerMatchingLifetimeScope("my-scope");

Instance Per Request 通常用于 web 应用程序，在每个 HTTP 请求期间共享一个实例。

builder.RegisterType<MyService>().As<IMyService>().InstancePerRequest();

Externally Owned 组件由外部代码管理生命周期，Autofac 不会在容器释放时释放该实例。

builder.RegisterType<MyService>().As<IMyService>().ExternallyOwned();

Instance Per Dependency 每次依赖请求时都会创建一个新实例。

builder.RegisterType<MyService>().As<IMyService>().InstancePerDependency();

默认生命周期

var builder = new ContainerBuilder();
builder.RegisterType<LenovoComputer>().As<IComputer>();
var container = builder.Build();
IComputer computer0 = container.Resolve<IComputer>();
IComputer computer1 = container.Resolve<IComputer>();
Console.WriteLine("computer0: " + computer0.GetHashCode());
Console.WriteLine("computer1: " + computer1.GetHashCode());
Console.WriteLine($"computer0 == computer1: {computer0 == computer1}");

输出

Zhy.IoC.Autofac.LenovoComputer - 被构造了
Zhy.IoC.Autofac.LenovoComputer - 被构造了
computer0: 32347029
computer1: 22687807
computer0 == computer1: False

单例生命周期

var builder = new ContainerBuilder();
builder.RegisterType<LenovoComputer>().As<IComputer>().SingleInstance();
var container = builder.Build();
IComputer computer0 = container.Resolve<IComputer>();
IComputer computer1 = container.Resolve<IComputer>();
Console.WriteLine("computer0: " + computer0.GetHashCode());
Console.WriteLine("computer1: " + computer1.GetHashCode());
Console.WriteLine($"computer0 == computer1: {computer0 == computer1}");

输出

Zhy.IoC.Autofac.LenovoComputer - 被构造了
computer0: 32347029
computer1: 32347029
computer0 == computer1: True

每个周期范围一个生命周期

var builder = new ContainerBuilder();
builder.RegisterType<LenovoComputer>().As<IComputer>().InstancePerLifetimeScope();
var container = builder.Build();
IComputer computer0 = container.Resolve<IComputer>();
using (var scope = container.BeginLifetimeScope())
{IComputer computer1 = scope.Resolve<IComputer>();IComputer computer2 = scope.Resolve<IComputer>();Console.WriteLine("computer0: " + computer0.GetHashCode());Console.WriteLine("computer1: " + computer1.GetHashCode());Console.WriteLine("computer2: " + computer2.GetHashCode());Console.WriteLine($"computer0 == computer1: {computer0 == computer1}");Console.WriteLine($"computer1 == computer2: {computer1 == computer2}");
}

输出

Zhy.IoC.Autofac.LenovoComputer - 被构造了
Zhy.IoC.Autofac.LenovoComputer - 被构造了
computer0: 32347029
computer1: 22687807
computer2: 22687807
computer0 == computer1: False
computer1 == computer2: True

依赖配置

Nuget

配置文件

Json

{"components": [{"type": "Zhy.IoC.Autofac.LenovoComputer,Zhy.IoC.Autofac","services": [{"type": "Zhy.IoC.Core.IComputer,Zhy.IoC.Core"}],"autoActivate": true,"instanceScope": "singleinstance"},{"type": "Zhy.IoC.Autofac.TogarKeyboard,Zhy.IoC.Autofac","services": [{"type": "Zhy.IoC.Core.IKeyboard,Zhy.IoC.Core"}],"autoActivate": true,"instanceScope": "singleinstance"},{"type": "Zhy.IoC.Autofac.LogitechMouse,Zhy.IoC.Autofac","services": [{"type": "Zhy.IoC.Core.IMouse,Zhy.IoC.Core"}],"parameters": {"places": 4},"autoActivate": true,"instanceScope": "singleinstance"},{"type": "Zhy.IoC.Autofac.Programmer,Zhy.IoC.Autofac","services": [{"type": "Zhy.IoC.Core.IPerson,Zhy.IoC.Core"}],"autoActivate": true,"instanceScope": "singleinstance"}]
}

XML

<?xml version="1.0" encoding="utf-8" ?>
<autofac><components name="0"><type>Zhy.IoC.Autofac.LenovoComputer,Zhy.IoC.Autofac</type><services name="0" type="Zhy.IoC.Core.IComputer,Zhy.IoC.Core" /></components><components name="1"><type>Zhy.IoC.Autofac.TogarKeyboard,Zhy.IoC.Autofac</type><services name="0" type="Zhy.IoC.Core.IKeyboard,Zhy.IoC.Core" /></components><components name="2"><type>Zhy.IoC.Autofac.LogitechMouse,Zhy.IoC.Autofac</type><services name="0" type="Zhy.IoC.Core.IMouse,Zhy.IoC.Core" /></components><components name="3"><type>Zhy.IoC.Autofac.Programmer,Zhy.IoC.Autofac</type><services name="0" type="Zhy.IoC.Core.IPerson,Zhy.IoC.Core" /></components>
</autofac>

调用

var config = new ConfigurationBuilder();
config.AddJsonFile("DI-Autofac.json");
// config.AddXmlFile("DI-Autofac.xml");
var module = new ConfigurationModule(config.Build());
var builder = new ContainerBuilder();
builder.RegisterModule(module);
var container = builder.Build();
IPerson programmer = container.Resolve<IPerson>();
programmer.Work();

输出

Zhy.IoC.Autofac.LenovoComputer - 被构造了
Zhy.IoC.Autofac.TogarKeyboard - 被构造了
Zhy.IoC.Autofac.LogitechMouse - 被构造了
Zhy.IoC.Autofac.Programmer - 被构造了
Programmers are building software...

AOP

Nuget安装

定义接口、实现类

public interface IMyService
{void DoWork();
}

public void DoWork()
{Console.WriteLine("Doing work...");
}

定义切面

using Castle.DynamicProxy;public class LoggingInterceptor : IInterceptor
{public void Intercept(IInvocation invocation){Console.WriteLine($"Invoking method {invocation.Method.Name} at {DateTime.Now}");invocation.Proceed();Console.WriteLine($"Method {invocation.Method.Name} has completed at {DateTime.Now}");}
}

容器配置

var builder = new ContainerBuilder();
builder.Register(c => new LoggingInterceptor());
builder.RegisterType<MyService>().As<IMyService>().EnableInterfaceInterceptors().InterceptedBy(typeof(LoggingInterceptor));
var container = builder.Build();
var service = container.Resolve<IMyService>();
service.DoWork();

输出

Invoking method DoWork at 2024/5/30 16:49:34
Doing work...
Method DoWork has completed at 2024/5/30 16:49:34

参考资料

IOC容器之Unity与AutoFac_unity autofac-CSDN博客

Autofac/src/Autofac at develop · autofac/Autofac (github.com)

控制容器的反转和依赖关系注入模式 (martinfowler.com)