设计模式-代理模式

    public abstract class Subject {
        /**
         * 主体类
         */
        public abstract void request();
    }

public class RealSubject extends extends Subject {
    @Override
    public void request() {
        System.out.println("真实的请求");
    }
}

public class Proxy extends Subject{
    private RealSubject realSubject;
    /**
     * 代理真实实体,使用它的真实方法
     */
    @Override
    public void request() {
        if (realSubject ==null){
            realSubject =new RealSubject();

        }
        realSubject.request();
    }
}

public class Test {
    public static void main(String[] args) {
        Proxy proxy =new Proxy();
        proxy.request();
    }
}