.Net Core5.0中Autofac依赖注入整合多层,项目中可直接用
目录
一、配置Autofac替换内置DI
1.安装Nuget包:Autofac,Autofac.Extensions.DependencyInjection
2.Program.cs中CreateHostBuilder方法后加上.UseServiceProviderFactory(new AutofacServiceProviderFactory()) ; 告诉程序要使用Autofac。
3.Startup.cs中增加方法ConfigureContainer(ContainerBuilder containerBuilder),实例注入的地方,配置完成。
/// <summary>
/// Autofac注册服务的地方,Autofac会自动调用
/// </summary>
/// <param name="containerBuilder"></param>
public void ConfigureContainer(ContainerBuilder containerBuilder)
{
}
二、构造函数注入
新建IUserService,类UserService,控制器UserController
public interface IUserService
{
public string GetUserName();
}
public class UserService
{
public string GetUserName()
{
return "张三";
}
}
public class UserController : Controller
{
private readonly IUserService _userService;
public UserController(IUserService userService)
{
_userService = userService;
}
public IActionResult Index()
{
string name = _userService.GetUserName();
return Content(name);
}
}
在上面的ConfigureContainer方法把UserService注入进来,默认是瞬时注入
瞬时注入:containerBuilder.RegisterType<UserService>().As<IUserService>().InstancePerDependency();;
单例注入:containerBuilder.RegisterType<UserService>().As<IUserService>().SingleInstance();
生命周期注入: containerBuilder.RegisterType<UserService>().As<IUserService>().InstancePerLifetimeScope();
/// <summary>
/// Autofac注册服务的地方,Autofac会自动调用
/// </summary>
/// <param name="containerBuilder"></param>
public void ConfigureContainer(ContainerBuilder containerBuilder)
{
//注册服务
containerBuilder.RegisterType<UserService>().As<IUserService>();
}
访问/User/Index,_userService成功注入,正确获取结果。
三、属性注入
1.把UserController改成属性注入形式,属性注入有一个问题,就是那些属性需要注入?全部注入没必要,父类也有很多属性,要按需注入,给属性增加一个自定义特性标识说明需要注入。
public class UserController : Controller
{
[AutowiredProperty]
private IUserService userService { get; set; }
public IActionResult Index()
{
string name = userService.GetUserName();
return Content(name);
}
}
2.新增自定义特性类AutowiredPropertyAttribute.cs
[AttributeUsage(AttributeTargets.Property)]//为了支持属性注入,只能打到属性上
public class AutowiredPropertyAttribute : Attribute
{
}
3.增加识别特性类AutowiredPropertySelector.cs
/// <summary>
/// IPropertySelector:查看属性上是否标记某一个特性
/// </summary>
public class AutowiredPropertySelector : IPropertySelector
{
public bool InjectProperty(PropertyInfo propertyInfo, object instance)
{
//判断属性的特性是否包含自定义的属性,标记有返回true
return propertyInfo.CustomAttributes.Any(s => s.AttributeType == typeof(AutowiredPropertyAttribute));
}
}
4.因为Controller 默认是由 Mvc 模块管理的,需要把控制器放到IOC容器中,在Startup.cs的ConfigureServices中增加
//让控制器实例由容器创建
services.Replace(ServiceDescriptor.Transient<IControllerActivator, ServiceBasedControllerActivator>());
5.把容器注册到IOC容器,在Startup.cs的ConfigureContainer()增加
//获取所有控制器类型并使用属性注入
Type[] controllersTypeAssembly = typeof(Startup).Assembly.GetExportedTypes()
.Where(type => typeof(ControllerBase).IsAssignableFrom(type)).ToArray();
containerBuilder.RegisterTypes(controllersTypeAssembly).PropertiesAutowired(new AutowiredPropertySelector());
6.验证结果,新增一个接口IOrderService.cs和一个实现类OrderService.cs做对比
public interface IOrderService
{
public string CreateOrder();
}
public class OrderService : IOrderService
{
public string CreateOrder()
{
return "下单成功";
}
}
把UserController改成
public class UserController : Controller
{
[AutowiredProperty]
private IUserService userService { get; set; }
private IOrderService orderService { get; set; }//不加属性注入标识
public IActionResult Index()
{
string name = userService.GetUserName();
return Content(name);
}
}
注入方法ConfigureContainer()增加
containerBuilder.RegisterType<OrderService>().As<IOrderService>();
运行程序,能看到增加了注入标识的userService注入成功,没加标识的orderService没有注入。
四、批量注入
实际项目中那么多需要注入的类,一个个写注册就不太现实了,需要一个可以批量注入的方法。
1.新建三个空接口IScopeDenpendency.cs,ISingletonDenpendency.cs,ITransitDenpendency.cs
/// <summary>
/// 瞬时注入
/// </summary>
public interface ITransitDenpendency
{
}
/// <summary>
/// 单例注入标识
/// </summary>
public interface ISingletonDenpendency
{
}
/// <summary>
/// 生命周期注入标识
/// </summary>
public interface IScopeDenpendency
{
}
2.把上面要注入的类实现上面的接口
3.新增一个IocManger类
/// <summary>
/// 批量注入扩展
/// </summary>
/// <param name="builder"></param>
/// <param name="assembly"></param>
public static void BatchAutowired(this ContainerBuilder builder, Assembly assembly)
{
var transientType = typeof(ITransitDenpendency); //瞬时注入
var singletonType = typeof(ISingletonDenpendency); //单例注入
var scopeType = typeof(IScopeDenpendency); //单例注入
//瞬时注入
builder.RegisterAssemblyTypes(assembly).Where(t => t.IsClass && !t.IsAbstract && t.GetInterfaces().Contains(transientType))
.AsSelf()
.AsImplementedInterfaces()
.InstancePerDependency()
.PropertiesAutowired(new AutowiredPropertySelector());
//单例注入
builder.RegisterAssemblyTypes(assembly).Where(t => t.IsClass && !t.IsAbstract && t.GetInterfaces().Contains(singletonType))
.AsSelf()
.AsImplementedInterfaces()
.SingleInstance()
.PropertiesAutowired(new AutowiredPropertySelector());
//生命周期注入
builder.RegisterAssemblyTypes(assembly).Where(t => t.IsClass && !t.IsAbstract && t.GetInterfaces().Contains(scopeType))
.AsSelf()
.AsImplementedInterfaces()
.InstancePerLifetimeScope()
.PropertiesAutowired(new AutowiredPropertySelector());
}
4.把注入类ConfigureContainer改成
/// <summary>
/// Autofac注册服务的地方,Autofac会自动调用
/// </summary>
/// <param name="containerBuilder"></param>
public void ConfigureContainer(ContainerBuilder containerBuilder)
{
//获取所有控制器类型并使用属性注入
Type[] controllersTypeAssembly = typeof(Startup).Assembly.GetExportedTypes()
.Where(type => typeof(ControllerBase).IsAssignableFrom(type)).ToArray();
containerBuilder.RegisterTypes(controllersTypeAssembly).PropertiesAutowired(new AutowiredPropertySelector());
//批量自动注入,把需要注入层的程序集传参数
containerBuilder.BatchAutowired(typeof(UserService).Assembly);
containerBuilder.BatchAutowired(typeof(UserRepository).Assembly);
}
5.防止startup.cs代码过多,建一个Module把注入代码搬走,新建AutofacRegisterModule.cs类把ConfigureContainer的代码移过去
public class AutofacRegisterModule:Autofac.Module
{
protected override void Load(ContainerBuilder builder)
{
//获取所有控制器类型并使用属性注入
Type[] controllersTypeAssembly = typeof(Startup).Assembly.GetExportedTypes()
.Where(type => typeof(ControllerBase).IsAssignableFrom(type)).ToArray();
builder.RegisterTypes(controllersTypeAssembly).PropertiesAutowired(new AutowiredPropertySelector());
//批量自动注入,把需要注入层的程序集传参数
builder.BatchAutowired(typeof(UserService).Assembly);
builder.BatchAutowired(typeof(UserRepository).Assembly);
}
}
ConfigureContainer的代码变成
/// <summary>
/// Autofac注册服务的地方,Autofac会自动调用
/// </summary>
/// <param name="containerBuilder"></param>
public void ConfigureContainer(ContainerBuilder containerBuilder)
{
containerBuilder.RegisterModule<AutofacRegisterModule>();
}
五、手动获取实例
手动获取实例的场景有静态帮助类中获取实例,例如redisHelper中获取注入的配置文件中的连接字符串
1.在上面的IocManager类中增加
private static object obj = new object();
private static ILifetimeScope _container { get; set; }
public static void InitContainer(ILifetimeScope container)
{
//防止过程中方法被调用_container发生改变
if (_container == null)
{
lock (obj)
{
if (_container == null)
{
_container = container;
}
}
}
}
/// <summary>
/// 手动获取实例
/// </summary>
/// <typeparam name="T"></typeparam>
/// <returns></returns>
public static T Resolve<T>()
{
return _container.Resolve<T>();
}
2.在Startup.cs的Configure()中增加
//获取Autofac容器上下文信息
IocManager.InitContainer(app.ApplicationServices.GetAutofacRoot());
3.验证,新建一个DataHelper.cs类
public class DataHelper
{
//手动注入UserService
private static IUserService userService = IocManager.Resolve<IUserService>();
public static string GetData()
{
return userService.GetUserName();
}
}
修改UserController用DataHelper的方法成功获取数据
六、其它用法
1.不用接口,直接注入实例
public class UserService :ITransitDenpendency
{
public string GetUserName()
{
return "张三";
}
}
2.一接口多实现
public class UserService :IUserService
{
public string GetUserName()
{
return "张三";
}
}
public class User2Service : IUserService
{
public string GetUserName()
{
return "张三2号";
}
}
最后:源码地址:https://github.com/weixiaolong325/.NetCore5.0AutofacDemo
演示项目结构:
.