JDK动态代理借助接口实现，目标类需是接口形式，代理类继承InvocationHandler类，通过反射方式动态创建目标类。

1.目标对象

public interface ByShoot {
	void byShoot(String size);
}

public class ShootFactory implements ByShoot{

	@Override
	public void byShoot(String size) {
		System.out.println("已经为您生产出了尺码为"+size+"的鞋子");
	}

}

2.代理类 关键字继承InvocationHandler类

public class LisiFactory implements InvocationHandler {

	// 被代理的对象
	private Object factory ;

	public Object getFactory() {
		return factory;
	}

	public void setFactory(Object factory) {
		this.factory = factory;
	}

	//ssm: Spring SpringMVC mybitys
	//Spring:AOP IOC +....
	//AOP:代理    (面向切面的编程)
	// 通过代理对象对方法进行增强
	@Override
	public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
		FrontService();
		Object retObject = method.invoke(factory, args);  //这里用了反射的思想，因为我们不知道调用的是那个工厂的那个方法
		endService();
		return null;
	}

	// 前置服务
	public void FrontService() {
		System.out.println("根据您的需求进行市场调研");
	}

	// 后置服务
	public void endService() {
		System.out.println("为您提供一条龙的包办服务");
	}
	
	//调度员工
	/**
	* 1 新建一名员工
	 * 2.告诉员工工厂地址
	 * this:绑定
	 * @return
	 */
	public Object getProxyInstance() {
		// TODO Auto-generated method stub
		return Proxy.newProxyInstance(factory.getClass().getClassLoader(), factory.getClass().getInterfaces(), this);
	}
	
	
}

3.测试类，买家

public class Test {
	public static void main(String[] args) {
		ClothesFactory clothesFactory = new ClothesFactory();
		ShootFactory shootFactory = new ShootFactory();
		LisiFactory lisiFactory = new LisiFactory();
		lisiFactory.setFactory(shootFactory);
		ByShoot yuangong1 = (ByShoot) lisiFactory.getProxyInstance();
		yuangong1.byShoot("42");
		lisiFactory.setFactory(clothesFactory);
		ByClothes yuangong  = (ByClothes) lisiFactory.getProxyInstance();
		yuangong.clothes("XXL");
	}
}