.NET中AOP的几种实现方案 - 青羽 - 博客园
Excerpt
通过代码的方式演示几种aop方案在.net中的实现。包括静态代理、.Net Remoting/RealProxy、EntLib\PIAB和Castle\DynamicProxy。
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
通过代理模式实现静态代理,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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