自动实现接口的实例，mybatis就是这样实现的

 InvocationHandler handler = new InvocationHandler() {

            /**
             * 代理对象 执行方法 方法参数
             */
            @Override
            public Object invoke(Object handler, Method method, Object[] params) throws Throwable {
                Dao dao = method.getAnnotation(Dao.class);
                if (null != dao) {
                    String value = dao.value();
                    System.out.println(value);
                    
                } else {
                    System.out.println("null");
                }

                Class<?> returnType = method.getReturnType();
                System.out.println(returnType.getName());
                return null;
            }
        };

        @SuppressWarnings("unchecked")
　　　　
        Class<Animal> cl = (Class<Animal>) Class.forName("zxj.proxy.Animal");

        Class<?>[] cc = { cl };
        Object instance = Proxy.newProxyInstance(Animal.class.getClassLoader(), cc, handler);
        System.out.println(instance.getClass().getName());

        Animal an = (Animal) instance;

        an.run();

        an.call();

        an.eat();

package zxj.proxy;

public interface Animal {

    @Dao("走")
    public void run();

    @Dao("吃")
    public void eat();

    @Dao("叫")
    public String call();
}