<dubbo:reference id="hello" interface="com.zhang.HelloService" check="false" />

EchoService echoService = (EchoService) appCtx.getBean("hello");

Object str = echoService.$echo("zhang");

public interface EchoService {

    Object $echo(Object message);

}

//AbstractProxyFactory

public <T> T getProxy(Invoker<T> invoker) throws RpcException {

    Class<?>[] interfaces = null;

    String config = invoker.getUrl().getParameter("interfaces");

    if (config != null && config.length() > 0) {

        String[] types = Constants.COMMA_SPLIT_PATTERN.split(config);

        if (types != null && types.length > 0) {

            interfaces = new Class<?>[types.length + 2];

            interfaces[0] = invoker.getInterface();

            interfaces[1] = EchoService.class;

            for (int i = 0; i < types.length; i ++) {

                interfaces[i + 1] = ReflectUtils.forName(types[i]);

            }

        }

    }

    if (interfaces == null) {

        //加入了EchoService接口

        interfaces = new Class<?>[] {invoker.getInterface(), EchoService.class};

    }

    //JavassistProxyFactory和JdkProxyFactory分别实现EchoService接口

    return getProxy(invoker, interfaces);

}

@Activate(group = Constants.PROVIDER, order = -110000)

public class EchoFilter implements Filter {

    public Result invoke(Invoker<?> invoker, Invocation inv) throws RpcException {

        if(inv.getMethodName().equals(Constants.$ECHO) 
　　　　　　　　&& inv.getArguments() != null && inv.getArguments().length == 1)

            return new RpcResult(inv.getArguments()[0]);

        return invoker.invoke(inv);

    }

}