标签：imessage 编程 mem ESS 分享图片 service 静态 his span
提供了对目标对象另外的访问方式;即通过代理对象访问目标对象.这样做的好处是:可以在目标对象实现的基础上,增强额外的功能操作,即扩展目标对象的功能.
这里使用到编程中的一个思想:不要随意去修改别人已经写好的代码或者方法,如果需改修改,可以通过代理的方式来扩展该方法
举个例子来说明代理的作用:假设我们想邀请一位明星,那么并不是直接连接明星,而是联系明星的经纪人,来达到同样的目的.明星就是一个目标对象,他只要负责活动中的节目,而其他琐碎的事情就交给他的代理人(经纪人)来解决.这就是代理思想在现实中的一个例子
静态代理在使用时,需要定义接口或者父类,被代理对象与代理对象一起实现相同的接口或者是继承相同父类.
class Program { static void Main(string[] args) { Member member = new Member() { Id=1,Name="test member"}; IMemberService baseMemberService = new MemberServiceImpl(); //代理原有业务类 MemberSerivceImplStaticProxy memberService = new MemberSerivceImplStaticProxy(baseMemberService); //遵守接口契约 string result = memberService.Create(member); System.Console.WriteLine(result); System.Console.ReadKey(); } } class Member { public int Id { get; set; } public String Name { get; set; } public override string ToString(){ return string.Format("Member[Id={0},Name={1}]", this.Id, this.Name); } } interface IMemberService { string Create(Member member); } class MemberServiceImpl : IMemberService { public string Create(Member member){ Console.WriteLine("create member:"+member); return "SUCCESS"; } } class MemberSerivceImplStaticProxy { private IMemberService target; public MemberSerivceImplStaticProxy(IMemberService target) { this.target = target; } public string Create(Member member){ before(member); string result= target.Create(member); after(member); return result; } private void before(Member member){ Console.WriteLine("before " + member); } private void after(Member member){ Console.WriteLine("after " + member); } }
动态代理有以下特点:
1.代理对象,不需要实现接口
2.代理对象的生成,是利用JDK的API,动态的在内存中构建代理对象(需要我们指定创建代理对象/目标对象实现的接口的类型)
3.动态代理也叫做:JDK代理,接口代理
class Program { static void Main(string[] args) { Member member = new Member() { Id=1,Name="test member"}; IMemberService baseMemberService = new MemberServiceImpl(); //代理原有业务类 IMemberService memberService = (IMemberService)new MemberServiceImplDynamicProxy(baseMemberService).GetTransparentProxy(); //遵守接口契约 string result = memberService.Create(member); System.Console.WriteLine(result); System.Console.ReadKey(); } } class Member { public int Id { get; set; } public String Name { get; set; } public override string ToString(){ return string.Format("Member[Id={0},Name={1}]", this.Id, this.Name); } } interface IMemberService { string Create(Member member); } class MemberServiceImpl : IMemberService { public string Create(Member member){ Console.WriteLine("create member:"+member); return "SUCCESS"; } } class MemberServiceImplDynamicProxy : System.Runtime.Remoting.Proxies.RealProxy { private IMemberService target; public MemberServiceImplDynamicProxy(IMemberService target) : base(typeof(IMemberService)){ this.target = target; } public override System.Runtime.Remoting.Messaging.IMessage Invoke(System.Runtime.Remoting.Messaging.IMessage msg){ System.Runtime.Remoting.Messaging.IMethodCallMessage callMessage = (System.Runtime.Remoting.Messaging.IMethodCallMessage)msg; Member member = callMessage.Args[0] as Member; before(member); object returnValue = callMessage.MethodBase.Invoke(this.target, callMessage.Args); after(member); return new System.Runtime.Remoting.Messaging.ReturnMessage(returnValue, new object[0], 0, null, callMessage); } private void before(Member member){ Console.WriteLine("before " + member); } private void after(Member member){ Console.WriteLine("after " + member); } }
为了让动态代理类更通用，可以对其调整为如下：
class DynamicProxyFactory : System.Runtime.Remoting.Proxies.RealProxy { private object target; public DynamicProxyFactory(object target, Type targetType) : base(targetType) { this.target = target; } public override System.Runtime.Remoting.Messaging.IMessage Invoke(System.Runtime.Remoting.Messaging.IMessage msg) { System.Runtime.Remoting.Messaging.IMethodCallMessage callMessage = (System.Runtime.Remoting.Messaging.IMethodCallMessage)msg; before(this.target); object returnValue = callMessage.MethodBase.Invoke(this.target, callMessage.Args); after(this.target); return new System.Runtime.Remoting.Messaging.ReturnMessage(returnValue, new object[0], 0, null, callMessage); } private void before(object member) { Console.WriteLine("before " + member); } private void after(object member) { Console.WriteLine("after " + member); } }
对应客户端调用时也要变，变为如下：
class Program { static void Main(string[] args) { Member member = new Member() { Id = 1, Name = "test member" }; IMemberService baseMemberService = new MemberServiceImpl(); //代理原有业务类 IMemberService memberService = (IMemberService)new DynamicProxyFactory(baseMemberService, typeof(IMemberService)).GetTransparentProxy(); //遵守接口契约 string result = memberService.Create(member); System.Console.WriteLine(result); System.Console.ReadKey(); } }
标签：imessage 编程 mem ESS 分享图片 service 静态 his span
原文地址：https://www.cnblogs.com/yy3b2007com/p/9065229.html
