net core天马行空系列：泛型仓储和声明式事物实现最优雅的crud操作

提示：扫一扫查出行
【扫一扫了解最新限行尾号】
复制提示

系列目录

1.net core天马行空系列：原生DI+AOP实现spring boot注解式编程

哈哈哈哈，大家好，我就是那个高产似母猪的三合，长久以来，我一直在思考，如何才能实现高效而简洁的仓储模式（不是DDD里的仓储，更准确的说就是数据库表的mapper），实现spring boot里那样利用注解实现事物操作，日有所思，终有所得，本篇文章浓缩了我对于仓储模式和工作单元模式理解的精华，希望能对大家有所帮助，如果哪里说错了，也希望大家不吝赐教。由于ef core本身就实现了这2种模式，再在ef core的基础上进行封装就失去了学习的意义，所以本文用到的是ORM方案是dapper+dapper.contrib, 这2个库皆出自名门stackexchange，也就是大名鼎鼎的爆栈啦，他们出品的库还有StackExchange.Redis，所以品质自不用说，开始正文前，先在nuget上安装这2个库。BTW,动态代理，注解式编程，AOP贯穿本系列始终，no bb，正文开始。

1.定义用到的类

上次讲飙车，这次我们讲，去加油站加油，加油这个过程呢，存在一个事物操作，那就是，加油站必须给我加足够的油，我才给他付钱，有点像银行转账，那么引申出2张表，汽车油量表(oilQuantity)和现金余额表(cashBalance)，对应的表结构和实体类如下，都比较简单，除了主键id，oilQuantity表只有一个油量quantity字段，cashBalance表只有一个余额balance字段,数据库使用的是mysql，实体类的注解TableAttribute使用的命名空间是System.ComponentModel.DataAnnotations.Schema。

CREATE TABLE test.oilQuantity (
id INT NOT NULL AUTO_INCREMENT,
quantity DECIMAL NULL,
CONSTRAINT caroil_pk PRIMARY KEY (id)
)
ENGINE=InnoDB
DEFAULT CHARSET=utf8
COLLATE=utf8_general_ci;

CREATE TABLE test.cashBalance (
id INT NOT NULL AUTO_INCREMENT,
balance DECIMAL NOT NULL,
CONSTRAINT cashbalance_pk PRIMARY KEY (id)
)
ENGINE=InnoDB
DEFAULT CHARSET=utf8
COLLATE=utf8_general_ci;

[Table("OilQuantity")]
public class OilQuantity
{
[Key]
public int Id { set; get; }
/// <summary>
/// 油量
/// </summary>
public decimal Quantity { set; get; }
}

[Table("CashBalance")]
public class CashBalance
{
[Key]
public int Id { set; get; }
/// <summary>
/// 余额
/// </summary>
public decimal Balance { set; get; }
}

定义数据库链接工厂类接口IDbFactory和他的实现类DbFactory，这个类主要负责数据库链接的创建，链接分为2种，一种是短链接，不开启事物的时候使用，用完即毁，每次获得都是全新的链接，另一种是长链接，用在事物操作中，DbFactory本身注册为scope级别，长链接创建后会保存在DbFactory的属性中，所以变相的实现了scope级别，同理，长链接的事务开启后也会被保存，用来在仓储中实现事物操作。

public interface IDbFactory:IDisposable
{
/// <summary>
/// 长链接
/// </summary>
IDbConnection LongDbConnection { get; } /// <summary>
/// 长链接的事物
/// </summary>
IDbTransaction LongDbTransaction { get; } /// <summary>
/// 短链接
/// </summary>
IDbConnection ShortDbConnection { get; } /// <summary>
/// 开启事务
/// </summary>
void BeginTransaction();
}

/// <summary>
/// 负责生成和销毁数据库链接
/// </summary>
public class DbFactory:IDbFactory
{
[Value("MysqlConnectionStr")]
public string MysqlConnectionStr { set; get; } /// <summary>
/// 长连接
/// </summary>
public IDbConnection LongDbConnection { private set; get; } /// <summary>
/// 长连接的事物
/// </summary>
public IDbTransaction LongDbTransaction { private set; get; } /// <summary>
/// 短链接
/// </summary>
public IDbConnection ShortDbConnection
{
get
{
var dbConnection = new MySqlConnection(MysqlConnectionStr);
dbConnection.Open();
return dbConnection;
}
} /// <summary>
/// 开启事务
/// </summary>
/// <returns></returns>
public void BeginTransaction()
{
if (LongDbConnection == null)
{
LongDbConnection = new MySqlConnection(MysqlConnectionStr);
LongDbConnection.Open();
LongDbTransaction = LongDbConnection.BeginTransaction();
}
} public void Dispose()
{
LongDbTransaction?.Dispose();
if (LongDbConnection?.State != ConnectionState.Closed)
{
LongDbConnection?.Close();
}
LongDbConnection?.Dispose();
LongDbTransaction = null;
LongDbConnection = null;
}
}

定义工作单元接口IUnitOfWork和他的实现类UnitOfWork，可以看到，IUnitOfWork中有一个引用次数ActiveNumber的属性，这个属性的作用主要是，如果一个标注了[Transactional]的方法里嵌套了另一个标注了[Transactional]的方法，我们就可以通过计数来确认，具体谁才是最外层的方法，从而达到不在内层方法里开启另一个事物，并且在内层方法结束时不会提前提交事务的效果。同时呢，UnitOfWork只负责与事务有关的操作，其他创建链接，创建事物等操作，都是由注入的IDbFactory完成的。

public interface IUnitOfWork : IDisposable
{
/// <summary>
/// 引用次数，开启一次事物加+1,当次数为0时提交，主要是为了防止事物嵌套
/// </summary>
int ActiveNumber { get; set; } /// <summary>
/// 开启事务
/// </summary>
void BeginTransaction(); /// <summary>
/// 提交
/// </summary>
void Commit(); /// <summary>
/// 事物回滚
/// </summary>
void RollBack();
}

public class UnitOfWork : IUnitOfWork
{
/// <summary>
/// 工作单元引用次数，当次数为0时提交，主要为了防止事物嵌套
/// </summary>
public int ActiveNumber { get; set; } = ; [Autowired]
public IDbFactory DbFactory { set; get; } public void BeginTransaction()
{
if (this.ActiveNumber == )
{
DbFactory.BeginTransaction();
Console.WriteLine("开启事务");
}
this.ActiveNumber++;
} public void Commit()
{
this.ActiveNumber--;
if (this.ActiveNumber == )
{
if (DbFactory.LongDbConnection != null)
{
try
{
DbFactory.LongDbTransaction.Commit();
}
catch (Exception e)
{
DbFactory.LongDbTransaction.Rollback();
Console.WriteLine(e);
throw;
}
finally
{
this.Dispose();
}
} Console.WriteLine("提交事务");
} } public void Dispose()
{
DbFactory.Dispose();
} public void RollBack()
{
if (this.ActiveNumber > && DbFactory.LongDbTransaction != null)
{
try
{
DbFactory.LongDbTransaction.Rollback();
}
catch (Exception e)
{
Console.WriteLine(e);
throw;
}
} Console.WriteLine("回滚事务");
}
}

泛型仓储接口IRepository<T>和他的实现类BaseRepository<T>，为了偷懒，只写了同步部分，异步同理，若使用异步，拦截器也要使用异步拦截器。BaseRepository中通过属性注入了IUnitOfWork和IDbFactory，IUnitOfWork主要负责告诉仓储，该使用长连接还是短链接，IDbFactory负责提供具体的链接和事物，而更细节的crud操作，则都是由dapper和dapper.contrib完成的。看代码var dbcon = Uow.ActiveNumber == 0 ? DbFactory.ShortDbConnection : DbFactory.LongDbConnection;可以看到通过判断uow的引用计数ActiveNumber 来判断使用的是长链接还是短链接，并且如果ActiveNumber==0的话，在数据库操作结束后就会释放掉链接。

public interface IRepository<T> where T : class
{
IList<T> GetAll();
T Get(object id); T Insert(T t);
IList<T> Insert(IList<T> t); void Update(T t);
void Update(IList<T> t); void Delete(IList<T> t);
void Delete(T t);
}

public class BaseRepository<T> : IRepository<T> where T : class
{
[Autowired]
public IUnitOfWork Uow { set; get; } [Autowired]
public IDbFactory DbFactory { set; get; } public IList<T> GetAll()
{
var dbcon = DbFactory.ShortDbConnection; var result = dbcon.GetAll<T>().ToList(); dbcon.Close();
dbcon.Dispose(); return result;
} public T Get(object id)
{
var dbcon = DbFactory.ShortDbConnection; var result = dbcon.Get<T>(id); dbcon.Close();
dbcon.Dispose(); return result;
} public T Insert(T t)
{
var dbcon = Uow.ActiveNumber == ? DbFactory.ShortDbConnection : DbFactory.LongDbConnection;
dbcon.Insert(t, DbFactory.LongDbTransaction); if (Uow.ActiveNumber == )
{
dbcon.Close();
dbcon.Dispose();
} return t;
} public IList<T> Insert(IList<T> t)
{
var dbcon = Uow.ActiveNumber == ? DbFactory.ShortDbConnection : DbFactory.LongDbConnection;
dbcon.Insert(t, DbFactory.LongDbTransaction); if (Uow.ActiveNumber == )
{
dbcon.Close();
dbcon.Dispose();
} return t;
} public void Delete(T t)
{
var dbcon = Uow.ActiveNumber == ? DbFactory.ShortDbConnection : DbFactory.LongDbConnection;
dbcon.Delete(t, DbFactory.LongDbTransaction); if (Uow.ActiveNumber == )
{
dbcon.Close();
dbcon.Dispose();
} } public void Delete(IList<T> t)
{
var dbcon = Uow.ActiveNumber == ? DbFactory.ShortDbConnection : DbFactory.LongDbConnection;
dbcon.Delete(t, DbFactory.LongDbTransaction); if (Uow.ActiveNumber == )
{
dbcon.Close();
dbcon.Dispose();
} } public void Update(T t)
{
var dbcon = Uow.ActiveNumber == ? DbFactory.ShortDbConnection : DbFactory.LongDbConnection;
dbcon.Update(t, DbFactory.LongDbTransaction); if (Uow.ActiveNumber == )
{
dbcon.Close();
dbcon.Dispose();
} } public void Update(IList<T> t)
{
var dbcon = Uow.ActiveNumber == ? DbFactory.ShortDbConnection : DbFactory.LongDbConnection;
dbcon.Update(t, DbFactory.LongDbTransaction);
if (Uow.ActiveNumber == )
{
dbcon.Close();
dbcon.Dispose();
} }
}

事物拦截器TransactionalInterceptor，在方法开始前，如果拦截到的方法具有[TransactionalAttribute]注解，则通过uow开启事务，在方法结束后，如果拦截到的方法具有[TransactionalAttribute]注解，则通过uow结束事务。

/// <summary>
/// 事物拦截器
/// </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}拦截前", invocation.Method.Name); var method = invocation.MethodInvocationTarget;
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}拦截后，返回值是{1}", invocation.Method.Name, invocation.ReturnValue); var method = invocation.MethodInvocationTarget;
if (method != null && method.GetCustomAttribute<TransactionalAttribute>() != null)
{
Uow.Commit();
}
}
}

IServiceCollection静态扩展类SummerBootExtentions.cs，和上一篇比较，主要就是添加了AddSbRepositoryService方法，这个方法主要通过反射获得由[TableAttribute]标注的实体类，并向IServiceCollection中添加相应的的仓储接口和相应的仓储实现类，为什么不用services.AddScoped(typeof(IRepository<>),typeof(BaseRepository<>));这种方法注入泛型仓储呢？因为net core原生DI并不支持泛型注入的工厂委托创建，那么就无法实现动态代理了，所以采用变通的方法，将通用泛型接口，转成具体的泛型接口，SummerBootExtentions.cs的另一个变动就是将ProxyGenerator注册成单例了，这样就可以利用缓存，提高创建动态代理的性能，SummerBootExtentions.cs代码如下：

public static class SummerBootExtentions
{
/// <summary>
/// 瞬时
/// </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>
/// 瞬时
/// </summary>
/// <param name="services"></param>
/// <param name="serviceType"></param>
/// <param name="implementationType"></param>
/// <param name="interceptorTypes"></param>
/// <returns></returns>
public static IServiceCollection AddSbTransient(this IServiceCollection services, Type serviceType,
Type implementationType, params Type[] interceptorTypes)
{
return services.AddSbService(serviceType, implementationType, ServiceLifetime.Transient, interceptorTypes);
} /// <summary>
/// 请求级别
/// </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>
/// 请求级别
/// </summary>
/// <param name="services"></param>
/// <param name="serviceType"></param>
/// <param name="implementationType"></param>
/// <param name="interceptorTypes"></param>
/// <returns></returns>
public static IServiceCollection AddSbScoped(this IServiceCollection services, Type serviceType,
Type implementationType, params Type[] interceptorTypes)
{
return services.AddSbService(serviceType, implementationType, ServiceLifetime.Scoped, interceptorTypes);
} /// <summary>
/// 单例
/// </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);
} /// <summary>
/// 单例
/// </summary>
/// <param name="services"></param>
/// <param name="serviceType"></param>
/// <param name="implementationType"></param>
/// <param name="interceptorTypes"></param>
/// <returns></returns>
public static IServiceCollection AddSbSingleton(this IServiceCollection services, Type serviceType,
Type implementationType, params Type[] interceptorTypes)
{
return services.AddSbService(serviceType, implementationType, 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)
{
//属性注入
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 proxyGenerator = provider.GetService<ProxyGenerator>();
var proxy = proxyGenerator.CreateInterfaceProxyWithTarget(serviceType, target, interceptors.ToArray()); return proxy;
}; var serviceDescriptor = new ServiceDescriptor(serviceType, Factory, lifetime);
services.Add(serviceDescriptor); return services;
} /// <summary>
/// 瞬时
/// </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>
/// 瞬时
/// </summary>
/// <param name="services"></param>
/// <param name="serviceType"></param>
/// <param name="interceptorTypes"></param>
/// <returns></returns>
public static IServiceCollection AddSbTransient(this IServiceCollection services, Type serviceType, params Type[] interceptorTypes)
{
return services.AddSbService(serviceType, ServiceLifetime.Transient, interceptorTypes);
} /// <summary>
/// 请求
/// </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>
/// 请求
/// </summary>
/// <param name="services"></param>
/// <param name="serviceType"></param>
/// <param name="interceptorTypes"></param>
/// <returns></returns>
public static IServiceCollection AddSbScoped(this IServiceCollection services, Type serviceType,
params Type[] interceptorTypes)
{
return services.AddSbService(serviceType, ServiceLifetime.Scoped, interceptorTypes);
} /// <summary>
/// 单例
/// </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);
} /// <summary>
/// 单例
/// </summary>
/// <param name="services"></param>
/// <param name="serviceType"></param>
/// <param name="interceptorTypes"></param>
/// <returns></returns>
public static IServiceCollection AddSbSingleton(this IServiceCollection services, Type serviceType, params Type[] interceptorTypes)
{
return services.AddSbService(serviceType, 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 proxyGenerator = provider.GetService<ProxyGenerator>(); var proxy = proxyGenerator.CreateClassProxy(serviceType, interceptors.ToArray()); var properties = serviceType.GetTypeInfo().DeclaredProperties; foreach (PropertyInfo info in properties)
{
//属性注入
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>
/// 添加summer boot扩展
/// </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;
} public static IServiceCollection AddSbRepositoryService(this IServiceCollection services, params Type[] interceptorTypes)
{
var types = AppDomain.CurrentDomain.GetAssemblies().SelectMany(it => it.GetTypes()); var tableType = types.Where(it => it.GetCustomAttribute<TableAttribute>() != null); foreach (var type in tableType)
{
var injectServiceType = typeof(IRepository<>).MakeGenericType(type);
var injectImplType = typeof(BaseRepository<>).MakeGenericType(type);
services.AddSbScoped(injectServiceType, injectImplType, interceptorTypes);
} return services;
}
}

定义一个加油的服务类接口IAddOilService和接口的实现类AddOilService，可以从代码中看到，我们通过属性注入添加了CashBalanceRepository和OilQuantityRepository，通过[Transactional]标注AddOil方法，使其成为事物性操作，AddOil主要就是初始化金额和油量，然后进行加减操作，最后更新。

public interface IAddOilService
{
void AddOil();
}

public class AddOilService : IAddOilService
{
[Autowired]
public IRepository<CashBalance> CashBalanceRepository { set; get; } [Autowired]
public IRepository<OilQuantity> OilQuantityRepository { set; get; } [Transactional]
public void AddOil()
{
//初始化金额
var cashBalance = CashBalanceRepository.Insert(new CashBalance() { Balance = });
//初始化油量
var oilQuantity = OilQuantityRepository.Insert(new OilQuantity() { Quantity = }); cashBalance.Balance -= ;
oilQuantity.Quantity += ; CashBalanceRepository.Update(cashBalance);
//throw new Exception("主动报错");
OilQuantityRepository.Update(oilQuantity);
}
}

修改Startup.cs中的ConfigureServices方法，代码如下：

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.AddSingleton<ProxyGenerator>(); services.AddSbScoped<Engine>(typeof(TransactionalInterceptor)); services.AddSbScoped<IUnitOfWork, UnitOfWork>();
services.AddScoped(typeof(TransactionalInterceptor)); services.AddSbScoped<ICar, Car>(typeof(TransactionalInterceptor)); services.AddSbScoped<IDbFactory, DbFactory>();
services.AddSbRepositoryService(typeof(TransactionalInterceptor));
services.AddSbScoped<IAddOilService, AddOilService>(typeof(TransactionalInterceptor));
}

控制器HomeController

public class HomeController : Controller
{
[Autowired]
public ICar Car { set; get; } [Autowired]
public IDistributedCache Cache { set; get; } [Value("description")]
public string Description { set; get; } [Autowired]
public IAddOilService AddOilService { set; get; } public IActionResult Index()
{ var car = Car; AddOilService.AddOil(); Car.Fire(); Console.WriteLine(Description); return View();
}
}