静态代理模式设计

public abstract class Subject{public abstract void request(); }public class RealSubject extends Subject{public void request(){System.out.println("From realsubject!");}}public class ProxySubject extends Subject{private RealSubject realsubject;public void request(){this.pre();if(realsubject==null){realsubject=new RealSubject();}realsubject.request();this.post();}private void pre(){System.out.println("pre!");}private void post(){System.out.println("post!");}}public class User{public static void main(String args[]){Subject subject=new ProxySubject();subject.request();}}