代理(Proxy)设计模式简介：
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：
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：
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();
}
}
基础才是编程人员应该深入研究的问题，比如:
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2）mysql索引存储结构&如何调优/b-tree特点、计算复杂度及影响复杂度的因素。。。
3）JVM运行组成与原理及调优
4）Java类加载器运行原理
5）Java中GC过程原理|使用的回收算法原理
6）Redis中hash一致性实现及与hash其他区别
7）Java多线程、线程池开发、管理Lock与Synchroined区别
8）Spring IOC/AOP 原理；加载过程的。。。