在动态代理中取Target

2016-07-30

动态代理取Target

本文作废，Spring有提供的工具，不用自己写，参考新文章

如果对某些函数执行了动态代理，那么可能造成反射无法获得函数原本对Class，而是获得的JDK动态代理，所以需要从动态代理中找到原本Object的指针


public class ReflectionUtil {

    /**
     * 获取 代理目标对象
     *
     * @param proxy 代理对象
     * @return 目标对象
     * @throws Exception
     */
    public static Object getTarget(Object proxy) throws Exception {
        // 不是代理对象
        if (!AopUtils.isAopProxy(proxy)) {
            return proxy;
        }
        // 如果是JdkDynamicProxy代理对象
        if (AopUtils.isJdkDynamicProxy(proxy)) {
            return getJdkDynamicProxyTargetObject(proxy);
        // 如果是Cglib代理对象
        } else {
            return getCglibProxyTargetObject(proxy);
        }


    }

    /**
     * 获取Cglib目标对象
     *
     * @param proxy 代理对象
     * @return 目标对象
     * @throws Exception
     */
    private static Object getCglibProxyTargetObject(Object proxy) throws Exception {
        Field h = proxy.getClass().getDeclaredField("CGLIB$CALLBACK_0");
        h.setAccessible(true);
        Object dynamicAdvisedInterceptor = h.get(proxy);
        Field advised = dynamicAdvisedInterceptor.getClass().getDeclaredField("advised");
        advised.setAccessible(true);
        Object target = ((AdvisedSupport) advised.get(dynamicAdvisedInterceptor)).getTargetSource().getTarget();
        return target;
    }

    /**
     * 获取JdkDynamicProxy目标对象
     *
     * @param proxy  代理对象
     * @return 目标对象
     * @throws Exception
     */
    private static Object getJdkDynamicProxyTargetObject(Object proxy) throws Exception {
        Field h = proxy.getClass().getSuperclass().getDeclaredField("h");
        h.setAccessible(true);
        AopProxy aopProxy = (AopProxy) h.get(proxy);
        Field advised = aopProxy.getClass().getDeclaredField("advised");
        advised.setAccessible(true);
        Object target = ((AdvisedSupport) advised.get(aopProxy)).getTargetSource().getTarget();
        return target;
    }
}