Java的代理模式例子

(1).  创建一个接口, 要代理的类和 代理类都将继承它
package stone;
public interface Image {
    public void show();
}
(2). 创建要被代理的类:
package stone;
public class BigImage implements Image {
    public BigImage() {
        try {
            Thread.sleep(3000);                      // 模拟大图片要用长时间来加载
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("loading big image ");
    }
    public void show() {
        System.out.println("show image");
    }
}
(3). 创建代理类
package stone;
public class TestProxy {
    public static void main(String[] args) {
        long start= System.currentTimeMillis();
        Image image= new ImageProxy(null);
        System.out.println("Load time:"+String.valueOf(System.currentTimeMillis()-start));
        image.show();
        System.out.println("Show time:"+String.valueOf(System.currentTimeMillis()-start));
    }
}
(4). 运行测试类,测试代理模式:
package stone;
public class TestProxy {
    public static void main(String[] args) {
        long start= System.currentTimeMillis();
        Image image= new ImageProxy(null);
        System.out.println("Load time:"+String.valueOf(Syste