README

syntax = "proto3";

option java_multiple_files = true;
option java_package = "org.apache.dubbo.demo";
option java_outer_classname = "DemoServiceProto";
option objc_class_prefix = "DEMOSRV";

package demoservice;

// The demo service definition.
service DemoService {
  rpc SayHello (HelloRequest) returns (HelloReply) {}
}

// The request message containing the user's name.
message HelloRequest {
  string name = 1;
}

// The response message containing the greetings
message HelloReply {
  string message = 1;
}

now dubbo support his own protoc plugin base on dubbo-maven-plugin

<plugin>
    <groupId>org.apache.dubbo</groupId>
    <artifactId>dubbo-maven-plugin</artifactId>
    <version>${dubbo.version}</version>
    <executions>
        <execution>
            <goals>
                <goal>compile</goal>
            </goals>
        </execution>
    </executions>
</plugin>

/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License.  You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

    package org.apache.dubbo.demo;

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.atomic.AtomicBoolean;

public final class DemoServiceDubbo {
private static final AtomicBoolean registered = new AtomicBoolean();

private static Class<?> init() {
Class<?> clazz = null;
try {
clazz = Class.forName(DemoServiceDubbo.class.getName());
if (registered.compareAndSet(false, true)) {
    org.apache.dubbo.common.serialize.protobuf.support.ProtobufUtils.marshaller(
    org.apache.dubbo.demo.HelloReply.getDefaultInstance());
    org.apache.dubbo.common.serialize.protobuf.support.ProtobufUtils.marshaller(
    org.apache.dubbo.demo.HelloRequest.getDefaultInstance());
}
} catch (ClassNotFoundException e) {
// ignore
}
return clazz;
}

private DemoServiceDubbo() {}

public static final String SERVICE_NAME = "org.apache.dubbo.demo.DemoService";

/**
* Code generated for Dubbo
*/
public interface IDemoService extends org.apache.dubbo.rpc.model.DubboStub {

static Class<?> clazz = init();

    org.apache.dubbo.demo.HelloReply sayHello(org.apache.dubbo.demo.HelloRequest request);

    CompletableFuture<org.apache.dubbo.demo.HelloReply> sayHelloAsync(org.apache.dubbo.demo.HelloRequest request);


}

}