net core天馬行空系列：原生DI+AOP實現spring boot註解式程式設計
阿新 • • 發佈：2019-08-28
寫過spring boot之後，那種無處不在的註解讓我非常喜歡，比如屬性注入@autowire，配置值注入@value，宣告式事物@Transactional等，都非常簡潔優雅，那麼我就在想，這些在net core裡能實現麼？經過一番摸索，終於實現並整理成此文。
IOC方面，個人非常喜歡net core自帶的DI，因為他註冊服務簡潔優雅，3個生命週期通俗易懂，所以就沒使用autofac等其他容器，AOP方面，使用了業內鼎鼎大名的Castle.DynamicProxy(簡稱DP),所以要在nuget中新增Castle.Core的依賴包，這裡大家可能會有疑問，利用mvc的actionFilter不就可以實現了麼，為什麼還要引用DP呢，因為呀，actionFilter只在controller層有效，普通類他就無能為力了，而DP無所不能。
1.定義註解和需要用到的類
屬性注入註解
[AttributeUsage(AttributeTargets.Property)]
public class AutowiredAttribute : Attribute
{
}
配置值注入註解
[AttributeUsage(AttributeTargets.Property)]
public class ValueAttribute : Attribute
{
public ValueAttribute(string value = "")
{
this.Value = value;
}
public string Value { get; }
}宣告式事物註解
[AttributeUsage(AttributeTargets.Method)]
public class TransactionalAttribute : Attribute
{
}
工作單元介面及實現類，用來實現事物操作，注入級別為scope，一次請求公用一個工作單元例項
public interface IUnitOfWork : IDisposable
{
/// <summary>
/// 開啟事務
/// </summary>
void BeginTransaction();
/// <summary>
/// 提交
/// </summary>
void Commit();
/// <summary>
/// 事物回滾
/// </summary>
void RollBack();
} public class UnitOfWork : IUnitOfWork
{
public void BeginTransaction()
{
Console.WriteLine("開啟事務");
}
public void Commit()
{
Console.WriteLine("提交事務");
}
public void Dispose()
{
//throw new System.NotImplementedException();
}
public void RollBack()
{
Console.WriteLine("回滾事務");
}
}
攔截器
/// <summary>
/// 事物攔截器
/// </summary>
public class TransactionalInterceptor : StandardInterceptor
{
private IUnitOfWork Uow { set; get; }
public TransactionalInterceptor(IUnitOfWork uow)
{
Uow = uow;
}
protected override void PreProceed(IInvocation invocation)
{
Console.WriteLine("{0}攔截前", invocation.Method.Name);
var method = invocation.TargetType.GetMethod(invocation.Method.Name);
if (method != null && method.GetCustomAttribute<TransactionalAttribute>() != null)
{
Uow.BeginTransaction();
}
}
protected override void PerformProceed(IInvocation invocation)
{
invocation.Proceed();
}
protected override void PostProceed(IInvocation invocation)
{
Console.WriteLine("{0}攔截後， 返回值是{1}", invocation.Method.Name, invocation.ReturnValue);
var method = invocation.TargetType.GetMethod(invocation.Method.Name);
if (method != null && method.GetCustomAttribute<TransactionalAttribute>() != null)
{
Uow.Commit();
}
}
}
用來測試注入效果的介面以及實現類，這裡我們定義一輛汽車，汽車擁有一個引擎（屬性注入），它能點火啟動，點火操作帶事物，這裡為了演示【介面-實現類】注入和【實現類】注入2種情況，引擎就沒新增介面，只有實現類，並且AOP攔截僅有【實現類】的類時，只能攔截虛方法，所以Start和Stop函式為虛擬函式。
/// <summary>
/// 汽車引擎
/// </summary>
public class Engine
{
[Value("HelpNumber")]
public string HelpNumber { set; get; }
public virtual void Start()
{
Console.WriteLine("發動機啟動");
Stop();
}
public virtual void Stop()
{
Console.WriteLine("發動機熄火,撥打求救電話" + HelpNumber);
}
}
public interface ICar
{
Engine Engine { set; get; }
void Fire();
}
public class Car : ICar
{
[Autowired]
public Engine Engine { set; get; }
[Value("oilNo")]
public int OilNo { set; get; }
[Transactional]
public void Fire()
{
Console.WriteLine("加滿" + OilNo + "號汽油,點火");
Engine.Start();
}
}
控制器HomeController
public class HomeController : Controller
{
[Autowired]
public ICar Car{ set; get; }
[Value("description")]
public string Description { set; get; }
public IActionResult Index()
{
var car = Car;
Console.WriteLine(Description);
Car.Fire();
return View();
}
}
修改appsettings.json，新增一些測試鍵值對，（如果測試時發現輸出的中文亂碼，把appsettings.json儲存為utf8格式即可），具體程式碼如下，
{
"Logging": {
"LogLevel": {
"Default": "Warning"
}
},
"AllowedHosts": "*",
"oilNo": 95,
"HelpNumber": "110",
"description": "我要開始飆車了"
}
2.效果圖
從上圖可以看到，正常注入，正常開啟攔截器和事務，正確讀取配置值。
從上圖可以看到，我們的控制器，ICar和Engine全部都是動態代理類，注入正常。
3.核心程式碼
第一部分，新增一個擴充套件類，名叫SummerBootExtentions.cs，程式碼如下
public static class SummerBootExtentions
{
/// <summary>
/// 瞬時
/// </summary>
/// <typeparam name="TService"></typeparam>
/// <typeparam name="TImplementation"></typeparam>
/// <param name="services"></param>
/// <param name="interceptorTypes"></param>
/// <returns></returns>
public static IServiceCollection AddSbTransient<TService, TImplementation>(this IServiceCollection services, params Type[] interceptorTypes)
{
return services.AddSbService(typeof(TService), typeof(TImplementation), ServiceLifetime.Transient, interceptorTypes);
}
/// <summary>
/// 請求級別
/// </summary>
/// <typeparam name="TService"></typeparam>
/// <typeparam name="TImplementation"></typeparam>
/// <param name="services"></param>
/// <param name="interceptorTypes"></param>
/// <returns></returns>
public static IServiceCollection AddSbScoped<TService, TImplementation>(this IServiceCollection services, params Type[] interceptorTypes)
{
return services.AddSbService(typeof(TService), typeof(TImplementation), ServiceLifetime.Scoped, interceptorTypes);
}
/// <summary>
/// 單例
/// </summary>
/// <typeparam name="TService"></typeparam>
/// <typeparam name="TImplementation"></typeparam>
/// <param name="services"></param>
/// <param name="interceptorTypes"></param>
/// <returns></returns>
public static IServiceCollection AddSbSingleton<TService, TImplementation>(this IServiceCollection services, params Type[] interceptorTypes)
{
return services.AddSbService(typeof(TService), typeof(TImplementation), ServiceLifetime.Singleton, interceptorTypes);
}
public static IServiceCollection AddSbService(this IServiceCollection services, Type serviceType, Type implementationType,
ServiceLifetime lifetime, params Type[] interceptorTypes)
{
services.Add(new ServiceDescriptor(implementationType, implementationType, lifetime));
object Factory(IServiceProvider provider)
{
var target = provider.GetService(implementationType);
var properties = implementationType.GetTypeInfo().DeclaredProperties;
foreach (PropertyInfo info in properties)
{
//屬性注入
if (info.GetCustomAttribute<AutowiredAttribute>() != null)
{
var propertyType = info.PropertyType;
var impl = provider.GetService(propertyType);
if (impl != null)
{
info.SetValue(target, impl);
}
}
//配置值注入
if (info.GetCustomAttribute<ValueAttribute>() is ValueAttribute valueAttribute)
{
var value = valueAttribute.Value;
if (provider.GetService(typeof(IConfiguration)) is IConfiguration configService)
{
var pathValue = configService.GetSection(value).Value;
if (pathValue != null)
{
var pathV = Convert.ChangeType(pathValue, info.PropertyType);
info.SetValue(target, pathV);
}
}
}
}
List<IInterceptor> interceptors = interceptorTypes.ToList()
.ConvertAll<IInterceptor>(interceptorType => provider.GetService(interceptorType) as IInterceptor);
var proxy = new ProxyGenerator().CreateInterfaceProxyWithTarget(serviceType, target, interceptors.ToArray());
return proxy;
};
var serviceDescriptor = new ServiceDescriptor(serviceType, Factory, lifetime);
services.Add(serviceDescriptor);
return services;
}
/// <summary>
/// 瞬時
/// </summary>
/// <typeparam name="TService"></typeparam>
/// <param name="services"></param>
/// <param name="interceptorTypes"></param>
/// <returns></returns>
public static IServiceCollection AddSbTransient<TService>(this IServiceCollection services, params Type[] interceptorTypes)
{
return services.AddSbService(typeof(TService), ServiceLifetime.Transient, interceptorTypes);
}
/// <summary>
/// 請求
/// </summary>
/// <typeparam name="TService"></typeparam>
/// <param name="services"></param>
/// <param name="interceptorTypes"></param>
/// <returns></returns>
public static IServiceCollection AddSbScoped<TService>(this IServiceCollection services, params Type[] interceptorTypes)
{
return services.AddSbService(typeof(TService), ServiceLifetime.Scoped, interceptorTypes);
}
/// <summary>
/// 單例
/// </summary>
/// <typeparam name="TService"></typeparam>
/// <param name="services"></param>
/// <param name="interceptorTypes"></param>
/// <returns></returns>
public static IServiceCollection AddSbSingleton<TService>(this IServiceCollection services, params Type[] interceptorTypes)
{
return services.AddSbService(typeof(TService), ServiceLifetime.Singleton, interceptorTypes);
}
public static IServiceCollection AddSbService(this IServiceCollection services, Type serviceType,
ServiceLifetime lifetime, params Type[] interceptorTypes)
{
if (services == null)
throw new ArgumentNullException(nameof(services));
if (serviceType == (Type)null)
throw new ArgumentNullException(nameof(serviceType));
object Factory(IServiceProvider provider)
{
List<IInterceptor> interceptors = interceptorTypes.ToList()
.ConvertAll<IInterceptor>(interceptorType => provider.GetService(interceptorType) as IInterceptor);
var proxy = new ProxyGenerator().CreateClassProxy(serviceType, interceptors.ToArray());
var properties = serviceType.GetTypeInfo().DeclaredProperties;
foreach (PropertyInfo info in properties)
{
//屬性注入
if (info.GetCustomAttribute<AutowiredAttribute>() != null)
{
var propertyType = info.PropertyType;
var impl = provider.GetService(propertyType);
if (impl != null)
{
info.SetValue(proxy, impl);
}
}
//配置值注入
if (info.GetCustomAttribute<ValueAttribute>() is ValueAttribute valueAttribute)
{
var value = valueAttribute.Value;
if (provider.GetService(typeof(IConfiguration)) is IConfiguration configService)
{
var pathValue = configService.GetSection(value).Value;
if (pathValue != null)
{
var pathV = Convert.ChangeType(pathValue, info.PropertyType);
info.SetValue(proxy, pathV);
}
}
}
}
return proxy;
};
var serviceDescriptor = new ServiceDescriptor(serviceType, Factory, lifetime);
services.Add(serviceDescriptor);
return services;
}
/// <summary>
/// 新增summer boot擴充套件
/// </summary>
/// <param name="builder"></param>
/// <returns></returns>
public static IMvcBuilder AddSB(this IMvcBuilder builder)
{
if (builder == null)
throw new ArgumentNullException(nameof(builder));
ControllerFeature feature = new ControllerFeature();
builder.PartManager.PopulateFeature<ControllerFeature>(feature);
foreach (Type type in feature.Controllers.Select<TypeInfo, Type>((Func<TypeInfo, Type>)(c => c.AsType())))
builder.Services.TryAddTransient(type, type);
builder.Services.Replace(ServiceDescriptor.Transient<IControllerActivator, SbControllerActivator>());
return builder;
}
}
View Code
第二部分，新增一個自定義控制器啟用類，用以替換掉mvc自帶的啟用類，這個類命名為SbControllerActivator.cs，程式碼如下
public class SbControllerActivator : IControllerActivator
{
/// <inheritdoc />
public object Create(ControllerContext actionContext)
{
if (actionContext == null)
throw new ArgumentNullException(nameof(actionContext));
Type serviceType = actionContext.ActionDescriptor.ControllerTypeInfo.AsType();
var target = actionContext.HttpContext.RequestServices.GetRequiredService(serviceType);
var properties = serviceType.GetTypeInfo().DeclaredProperties;
var proxy = new ProxyGenerator().CreateClassProxyWithTarget(serviceType, target);
foreach (PropertyInfo info in properties)
{
//屬性注入
if (info.GetCustomAttribute<AutowiredAttribute>() != null)
{
var propertyType = info.PropertyType;
var impl = actionContext.HttpContext.RequestServices.GetService(propertyType);
if (impl != null)
{
info.SetValue(proxy, impl);
}
}
//配置值注入
if (info.GetCustomAttribute<ValueAttribute>() is ValueAttribute valueAttribute)
{
var value = valueAttribute.Value;
if (actionContext.HttpContext.RequestServices.GetService(typeof(IConfiguration)) is IConfiguration configService)
{
var pathValue = configService.GetSection(value).Value;
if (pathValue != null)
{
var pathV = Convert.ChangeType(pathValue, info.PropertyType);
info.SetValue(proxy, pathV);
}
}
}
}
return proxy;
}
/// <inheritdoc />
public virtual void Release(ControllerContext context, object controller)
{
}
}
View Code
第三部分，在Startup.cs中，修改ConfigureServices方法如下
public void ConfigureServices(IServiceCollection services)
{
services.Configure<CookiePolicyOptions>(options =>
{
// This lambda determines whether user consent for non-essential cookies is needed for a given request.
options.CheckConsentNeeded = context => true;
options.MinimumSameSitePolicy = SameSiteMode.None;
});
services.AddMvc()
.SetCompatibilityVersion(CompatibilityVersion.Version_2_1)
.AddSB();
services.AddSbScoped<Engine>(typeof(TransactionalInterceptor));
services.AddScoped<IUnitOfWork,UnitOfWork>();
services.AddScoped(typeof(TransactionalInterceptor));
services.AddSbScoped<ICar, Car>(typeof(TransactionalInterceptor));
}
從上面程式碼我們可以看到，在addMvc後加上了我們替換預設控制器的AddSB方法，接管了控制器的生成。AddSbScoped<Engine>和AddSbScoped<ICar, Car>這種新增依賴注入的方式也保持了net core自帶DI的原滋原味，簡潔優雅，並且實現了動態代理，只需要在引數裡新增攔截器，就能實時攔截，這裡引數為params Type[],可以新增N個攔截器。
4.寫在最後
在部落格園潛水了好幾年，見證了net core從1.0到快出3.0，這也是第一次嘗試著寫部落格，為net core的發揚光大儘自己的一份力。
&n