import java.lang.annotation.Documented;

import java.lang.annotation.ElementType;

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.lang.annotation.Target;

@Documented

@Retention(RetentionPolicy.RUNTIME)

@Target(ElementType.METHOD)

public @interface MethodAnnotation {

    String name() default "Default Annotation Name";

    String url() default "default.com";

}

public interface IProxyTest {

    @MethodAnnotation()

    public void testMethodAnnotation();

    @MethodAnnotation(name="亚马逊",url="z.cn")

    public void testMethodAnnotationWithValue();

}

public class ProxyTestImpl implements IProxyTest {

    public void testMethodAnnotation() {

        System.out.println("UseAnnotion->testMethodAnnotation");

    }

    public void testMethodAnnotationWithValue() {

        System.out.println("UseAnnotion->testMethodAnnotationWithValue");

    }

}

import java.lang.reflect.InvocationHandler;

import java.lang.reflect.Method;

import java.lang.reflect.Proxy;

public class LogProxy implements InvocationHandler {

    private static int count = 0;

    private Object target;

    private LogProxy() {

    }

    private static Object getInstance(Object o) {

        LogProxy lp = new LogProxy();

        lp.target = o;

        Object result = Proxy.newProxyInstance(o.getClass().getClassLoader(), o

                .getClass().getInterfaces(), lp);//代理对象

        return result;

    }

    @Override

    public Object invoke(Object proxy, Method method, Object[] args)

            throws Throwable {

        if (method.isAnnotationPresent(MethodAnnotation.class)) {

            MethodAnnotation annotation = method

                    .getAnnotation(MethodAnnotation.class);

            count++;//使用场景：统计接口的使用次数，可以在性能范围内降级

            System.out.println("执行方法" + method.getName() + ":" + count);

        }

        Object obj = method.invoke(target, args);

        return obj;

    }

    public static void main(String[] args) {

        IProxyTest ua = new ProxyTestImpl();

        IProxyTest lp = (IProxyTest) LogProxy.getInstance(ua);

        lp.testMethodAnnotation();

        lp.testMethodAnnotationWithValue();

    }

}