.NET中AOP的几种实现方案

AOP在.NET中的应用，个人也属于学习阶段，欢迎大家拍砖！

本文的例子模拟用户注册的场景，主要通过代码演示几种方案的实现方式。

静态代理

通过装饰模式实现静态代理，大家一看代码基本就明白了。

用户注册接口和实现

public interface IUserProcessor

{

void RegUser(User user);

}

public class UserProcessor : IUserProcessor

{

public void RegUser(User user)

{

Console.WriteLine("用户已注册。Name:{0},PassWord:{1}", user.Name, user.PassWord);

}

}

通过静态编写代码的方式，装饰上面的用户注册

public class UserProcessorDecorator:IUserProcessor

{

public IUserProcessor UserProcessor { get; set; }

public UserProcessorDecorator(IUserProcessor userprocessor)

{

UserProcessor = userprocessor;

}

public void RegUser(User user)

{

PreProceed(user);

UserProcessor.RegUser(user);

PostProceed(user);

}

public void PreProceed(User user)

{

Console.WriteLine("方法执行前");

}

public void PostProceed(User user)

{

Console.WriteLine("方法执行后");

}

}

客户端调用

public class Client

{

public static void Run()

{

try

{

User user = new User() { Name = "lee", PassWord = "123123123123" };

IUserProcessor userprocessor = new UserProcessorDecorator(new UserProcessor());

userprocessor.RegUser(user);

}

catch (Exception ex)

{

throw ex;

}

}

}

输出

方法执行前

用户已注册。Name:lee,PassWord:123123123123

方法执行后
动态代理

1、使用.Net Remoting/RealProxy

采用TransparentProxy和RealProxy实现对象的代理，实现思路如下：Client -TransparentProxy - RealProxy - Target Object

下面实现自定义的TransparentProxy和RealProxy

using System.Runtime.Remoting.Proxies;

using System.Runtime.Remoting.Messaging;

//RealProxy

public class MyRealProxy<T>:RealProxy

{

private T _target;

public MyRealProxy(T target) : base(typeof(T))

{

this._target = target;

}

public override IMessage Invoke(IMessage msg)

{

PreProceede(msg);

IMethodCallMessage callMessage = (IMethodCallMessage)msg;

object returnValue = callMessage.MethodBase.Invoke(this._target, callMessage.Args);

PostProceede(msg);

return new ReturnMessage(returnValue, new object[0], 0, null, callMessage);

}

public void PreProceede(IMessage msg)

{

Console.WriteLine("方法执行前");

}

public void PostProceede(IMessage msg)

{

Console.WriteLine("方法执行后");

}

}

//TransparentProxy

public static class TransparentProxy

{

public static T Create<T>()

{

T instance = Activator.CreateInstance<T>();

MyRealProxy<T> realProxy = new MyRealProxy<T>(instance);

T transparentProxy = (T)realProxy.GetTransparentProxy();

return transparentProxy;

}

}

用户注册接口和实现

public interface IUserProcessor

{

void RegUser(User user);

}

public class UserProcessor : MarshalByRefObject, IUserProcessor

{

public void RegUser(User user)

{

Console.WriteLine("用户已注册。");

}

}

客户端调用

public class Client

{

public static void Run()

{

try

{

User user = new User() { Name = "lee", PassWord = "123123123123" };

UserProcessor userprocessor = TransparentProxy.Create<UserProcessor>();

userprocessor.RegUser(user);

}

catch (Exception ex)

{

throw ex;

}

}

}

输出

方法执行前

用户已注册。Name:lee,PassWord:123123123123

方法执行后

2、使用EntLib/PIAB

自定义CallHandler，这里定义两个CallHandler分别用于参数检查和日志记录。

using Microsoft.Practices.Unity.InterceptionExtension;

public class UserHandler:ICallHandler

{

public int Order { get; set; }

public IMethodReturn Invoke(IMethodInvocation input, GetNextHandlerDelegate getNext)

{

User user = input.Inputs[0] as User;

if (user.PassWord.Length < 10)

{

return input.CreateExceptionMethodReturn(new UserException("密码长度不能小于10位"));

}

Console.WriteLine("参数检测无误");

return getNext()(input, getNext);

}

}

public class LogHandler:ICallHandler

{

public int Order { get; set; }

public IMethodReturn Invoke(IMethodInvocation input, GetNextHandlerDelegate getNext)

{

User user = input.Inputs[0] as User;

Log log = new Log() { Message = string.Format("RegUser:Username:{0},Password:{1}", user.Name, user.PassWord), Ctime = DateTime.Now };

Console.WriteLine("日志已记录，Message:{0},Ctime:{1}",log.Message,log.Ctime);

var messagereturn = getNext()(input, getNext);

return messagereturn;

}

}

定义对应的HandlerAttribute

using Microsoft.Practices.Unity.InterceptionExtension;

using Microsoft.Practices.Unity;

public class UserHandlerAttribute : HandlerAttribute

{

public override ICallHandler CreateHandler(IUnityContainer container)

{

ICallHandler handler = new UserHandler(){Order=this.Order};

return handler;

}

}

public class LogHandlerAttribute:HandlerAttribute

{

public int Order { get; set; }

public override ICallHandler CreateHandler(IUnityContainer container)

{

return new LogHandler() { Order = this.Order };

}

}

用户注册接口和实现，这里通过为接口添加attribute的方式实现。order值表示执行顺序，值小的先执行。

[LogHandlerAttribute(Order=2)]

[UserHandlerAttribute(Order=1)]

public interface IUserProcessor

{

void RegUser(User user);

}

public class UserProcessor : MarshalByRefObject,IUserProcessor

{

public void RegUser(User user)

{

Console.WriteLine("用户已注册。");

}

}

客户端调用

using Microsoft.Practices.EnterpriseLibrary.PolicyInjection;



public class Client

{

public static void Run()

{

try

{

User user = new User() { Name = "lee", PassWord = "123123123123" };

UserProcessor userprocessor = PolicyInjection.Create<UserProcessor>();

userprocessor.RegUser(user);

}

catch(Exception ex)

{

throw ex;

}

}

}

输出：

参数检测无误

日志已记录，Message:RegUser:Username:lee,Password:123123123123,Ctime:2010-12-22

6:14:59

用户已注册。

3、使用Castle/DynamicProxy

自定义Interceptor

public class MyInterceptor : IInterceptor

{

public void Intercept(IInvocation invocation)

{

PreProceed(invocation);

invocation.Proceed();

PostProceed(invocation);

}

public void PreProceed(IInvocation invocation)

{

Console.WriteLine("方法执行前");

}

public void PostProceed(IInvocation invocation)

{

Console.WriteLine("方法执行后");

}

}

用户注册接口和实现

public interface IUserProcessor

{

void RegUser(User user);

}

public class UserProcessor : IUserProcessor

{

public virtual void RegUser(User user)

{

Console.WriteLine("用户已注册。Name:{0},PassWord:{1}", user.Name, user.PassWord);

}

}

客户端调用

public class Client

{

public static void Run()

{

try

{

ProxyGenerator generator = new ProxyGenerator();

MyInterceptor interceptor = new MyInterceptor();

UserProcessor userprocessor = generator.CreateClassProxy<UserProcessor>(interceptor);

User user= new User() { Name = "lee", PassWord = "123123123123" };

userprocessor.RegUser(user);

}

catch (Exception ex)

{

throw ex;

}

}

}

输出

方法执行前

用户已注册。Name:lee,PassWord:123123123123

方法执行后
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