我正在查看代理模式，对我来说，它看起来非常像装饰器、适配器和桥接模式。我是不是误解了什么?有什么不同?为什么我要使用代理模式而不是其他模式?在过去的实际项目中，您是如何使用它们的?
当前回答
我相信代码会给出一个清晰的想法(补充其他答案)。请参见下面，(关注类实现和包装的类型)
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace TestConsole
{
class Program
{
static void Main(string[] args)
{
/* Proxy */
Console.WriteLine(Environment.NewLine);
Console.WriteLine("PROXY");
Console.WriteLine(Environment.NewLine);
//instead of creating here create using a factory method, the facory method will return the proxy
IReal realProxy = new RealProxy();
Console.WriteLine("calling do work with the proxy object ");
realProxy.DoWork();
Console.WriteLine(Environment.NewLine);
Console.WriteLine("ADAPTER");
Console.WriteLine(Environment.NewLine);
/*Adapter*/
IInHand objectIHave = new InHand();
Api myApi = new Api();
//myApi.SomeApi(objectIHave); /*I cant do this, use a adapter then */
IActual myAdaptedObject = new ActualAdapterForInHand(objectIHave);
Console.WriteLine("calling api with my adapted obj");
myApi.SomeApi(myAdaptedObject);
Console.WriteLine(Environment.NewLine);
Console.WriteLine("DECORATOR");
Console.WriteLine(Environment.NewLine);
/*Decorator*/
IReady maleReady = new Male();
Console.WriteLine("now male is going to get ready himself");
maleReady.GetReady();
Console.WriteLine(Environment.NewLine);
IReady femaleReady = new Female();
Console.WriteLine("now female is going to get ready her self");
femaleReady.GetReady();
Console.WriteLine(Environment.NewLine);
IReady maleReadyByBeautician = new Beautician(maleReady);
Console.WriteLine("now male is going to get ready by beautician");
maleReadyByBeautician.GetReady();
Console.WriteLine(Environment.NewLine);
IReady femaleReadyByBeautician = new Beautician(femaleReady);
Console.WriteLine("now female is going to get ready by beautician");
femaleReadyByBeautician.GetReady();
Console.WriteLine(Environment.NewLine);
Console.ReadLine();
}
}
/*Proxy*/
public interface IReal
{
void DoWork();
}
public class Real : IReal
{
public void DoWork()
{
Console.WriteLine("real is doing work ");
}
}
public class RealProxy : IReal
{
IReal real = new Real();
public void DoWork()
{
real.DoWork();
}
}
/*Adapter*/
public interface IActual
{
void DoWork();
}
public class Api
{
public void SomeApi(IActual actual)
{
actual.DoWork();
}
}
public interface IInHand
{
void DoWorkDifferently();
}
public class InHand : IInHand
{
public void DoWorkDifferently()
{
Console.WriteLine("doing work slightly different ");
}
}
public class ActualAdapterForInHand : IActual
{
IInHand hand = null;
public ActualAdapterForInHand()
{
hand = new InHand();
}
public ActualAdapterForInHand(IInHand hnd)
{
hand = hnd;
}
public void DoWork()
{
hand.DoWorkDifferently();
}
}
/*Decorator*/
public interface IReady
{
void GetReady();
}
public class Male : IReady
{
public void GetReady()
{
Console.WriteLine("Taking bath.. ");
Console.WriteLine("Dress up....");
}
}
public class Female : IReady
{
public void GetReady()
{
Console.WriteLine("Taking bath.. ");
Console.WriteLine("Dress up....");
Console.WriteLine("Make up....");
}
}
//this is a decorator
public class Beautician : IReady
{
IReady ready = null;
public Beautician(IReady rdy)
{
ready = rdy;
}
public void GetReady()
{
ready.GetReady();
Console.WriteLine("Style hair ");
if (ready is Female)
{
for (int i = 1; i <= 10; i++)
{
Console.WriteLine("doing ready process " + i);
}
}
}
}
}
其他回答
我相信代码会给出一个清晰的想法(补充其他答案)。请参见下面，(关注类实现和包装的类型)
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace TestConsole
{
class Program
{
static void Main(string[] args)
{
/* Proxy */
Console.WriteLine(Environment.NewLine);
Console.WriteLine("PROXY");
Console.WriteLine(Environment.NewLine);
//instead of creating here create using a factory method, the facory method will return the proxy
IReal realProxy = new RealProxy();
Console.WriteLine("calling do work with the proxy object ");
realProxy.DoWork();
Console.WriteLine(Environment.NewLine);
Console.WriteLine("ADAPTER");
Console.WriteLine(Environment.NewLine);
/*Adapter*/
IInHand objectIHave = new InHand();
Api myApi = new Api();
//myApi.SomeApi(objectIHave); /*I cant do this, use a adapter then */
IActual myAdaptedObject = new ActualAdapterForInHand(objectIHave);
Console.WriteLine("calling api with my adapted obj");
myApi.SomeApi(myAdaptedObject);
Console.WriteLine(Environment.NewLine);
Console.WriteLine("DECORATOR");
Console.WriteLine(Environment.NewLine);
/*Decorator*/
IReady maleReady = new Male();
Console.WriteLine("now male is going to get ready himself");
maleReady.GetReady();
Console.WriteLine(Environment.NewLine);
IReady femaleReady = new Female();
Console.WriteLine("now female is going to get ready her self");
femaleReady.GetReady();
Console.WriteLine(Environment.NewLine);
IReady maleReadyByBeautician = new Beautician(maleReady);
Console.WriteLine("now male is going to get ready by beautician");
maleReadyByBeautician.GetReady();
Console.WriteLine(Environment.NewLine);
IReady femaleReadyByBeautician = new Beautician(femaleReady);
Console.WriteLine("now female is going to get ready by beautician");
femaleReadyByBeautician.GetReady();
Console.WriteLine(Environment.NewLine);
Console.ReadLine();
}
}
/*Proxy*/
public interface IReal
{
void DoWork();
}
public class Real : IReal
{
public void DoWork()
{
Console.WriteLine("real is doing work ");
}
}
public class RealProxy : IReal
{
IReal real = new Real();
public void DoWork()
{
real.DoWork();
}
}
/*Adapter*/
public interface IActual
{
void DoWork();
}
public class Api
{
public void SomeApi(IActual actual)
{
actual.DoWork();
}
}
public interface IInHand
{
void DoWorkDifferently();
}
public class InHand : IInHand
{
public void DoWorkDifferently()
{
Console.WriteLine("doing work slightly different ");
}
}
public class ActualAdapterForInHand : IActual
{
IInHand hand = null;
public ActualAdapterForInHand()
{
hand = new InHand();
}
public ActualAdapterForInHand(IInHand hnd)
{
hand = hnd;
}
public void DoWork()
{
hand.DoWorkDifferently();
}
}
/*Decorator*/
public interface IReady
{
void GetReady();
}
public class Male : IReady
{
public void GetReady()
{
Console.WriteLine("Taking bath.. ");
Console.WriteLine("Dress up....");
}
}
public class Female : IReady
{
public void GetReady()
{
Console.WriteLine("Taking bath.. ");
Console.WriteLine("Dress up....");
Console.WriteLine("Make up....");
}
}
//this is a decorator
public class Beautician : IReady
{
IReady ready = null;
public Beautician(IReady rdy)
{
ready = rdy;
}
public void GetReady()
{
ready.GetReady();
Console.WriteLine("Style hair ");
if (ready is Female)
{
for (int i = 1; i <= 10; i++)
{
Console.WriteLine("doing ready process " + i);
}
}
}
}
}
在使用web服务时，我经常使用它。代理模式可能应该重命名为更实用的东西，比如“包装器模式”。我也有一个库，是一个代理到MS Excel。它使自动化Excel变得非常容易，而不必担心背景细节，如安装了什么版本(如果有的话)。
这是引用自 头部优先的设计模式
定义属于书。例子属于我。
装饰器——不改变界面，但增加了责任。假设你有一个汽车界面， 当您为不同型号的汽车(s, sv, sl)实现此功能时，您可能需要为某些型号添加更多的职责。比如有天窗，安全气囊等。
适配器—将一个接口转换为另一个接口。你有一个汽车界面，你想让它像吉普车一样工作。所以你把车开过来，改装成吉普车。因为这不是真正的吉普车。但它就像一辆吉普车。
Facade -使界面更简单。假设你有汽车、飞机、轮船接口。实际上，你所需要的只是一个将人从一个位置发送到另一个位置的类。你想让门面决定用什么车。然后将所有这些接口引用收集到一个保护伞下，并让它决定/委托以保持简单。
首先:“facade不仅简化了接口，还将客户端与子系统解耦 的组件。 外观和适配器可以包装多个类，但是外观的目的是简化 适配器的作用是将接口转换为不同的东西。”
它们非常相似，而且它们之间的线条是灰色的。我建议您阅读c2 wiki中的代理模式和装饰器模式条目。
那里的条目和讨论相当广泛，也链接到其他相关文章。顺便说一下，c2 wiki在了解不同模式之间的细微差别时非常有用。
总结c2项，我认为装饰器添加/更改行为，但代理与访问控制(延迟实例化，远程访问，安全等)有更多关系。但正如我所说，它们之间的界线是灰色的，我看到对代理的引用很容易被视为装饰器，反之亦然。
正如Bill的回答所说，它们的用例是不同的。
它们的结构也是如此。
Proxy and Decorator both have the same interface as their wrapped types, but the proxy creates an instance under the hood, whereas the decorator takes an instance in the constructor. Adapter and Facade both have a different interface than what they wrap. But the adapter derives from an existing interface, whereas the facade creates a new interface. Bridge and Adapter both point at an existing type. But the bridge will point at an abstract type, and the adapter might point to a concrete type. The bridge will allow you to pair the implementation at runtime, whereas the adapter usually won't.
