flatbuffers 可以应用到游戏中。媲美google protobuffer。

https://github.com/google/flatbuffers

http://google.github.io/flatbuffers/index.html

下载flatbuffers 编译对应平台的flatc。

接下来是编写fbs:

namespace com.dc.gameserver.genflat;table LoginRequest{msgID:int=1;username:string;password:string;time:long;
}
///table LoginResponse{msgID:int=2;time:long;uid:string;
}

详细说明见：http://google.github.io/flatbuffers/md__schemas.html

flatc脚本方式：http://google.github.io/flatbuffers/md__compiler.html

flatc.exe  -j   -o ../../java/ game.fbs

会生成对应的java文件.

// automatically generated, do not modifypackage com.dc.gameserver.genflat;import com.google.flatbuffers.FlatBufferBuilder;
import com.google.flatbuffers.Table;import java.nio.ByteBuffer;
import java.nio.ByteOrder;public class LoginRequest extends Table {public static LoginRequest getRootAsLoginRequest(ByteBuffer _bb) { return getRootAsLoginRequest(_bb, new LoginRequest()); }public static LoginRequest getRootAsLoginRequest(ByteBuffer _bb, LoginRequest obj) { _bb.order(ByteOrder.LITTLE_ENDIAN); return (obj.__init(_bb.getInt(_bb.position()) + _bb.position(), _bb)); }public LoginRequest __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; return this; }public int msgID() { int o = __offset(4); return o != 0 ? bb.getInt(o + bb_pos) : 1; }public String username() { int o = __offset(6); return o != 0 ? __string(o + bb_pos) : null; }public ByteBuffer usernameAsByteBuffer() { return __vector_as_bytebuffer(6, 1); }public String password() { int o = __offset(8); return o != 0 ? __string(o + bb_pos) : null; }public ByteBuffer passwordAsByteBuffer() { return __vector_as_bytebuffer(8, 1); }public long time() { int o = __offset(10); return o != 0 ? bb.getLong(o + bb_pos) : 0; }public static int createLoginRequest(FlatBufferBuilder builder,int msgID,int username,int password,long time) {builder.startObject(4);LoginRequest.addTime(builder, time);LoginRequest.addPassword(builder, password);LoginRequest.addUsername(builder, username);LoginRequest.addMsgID(builder, msgID);return LoginRequest.endLoginRequest(builder);}public static void startLoginRequest(FlatBufferBuilder builder) { builder.startObject(4); }public static void addMsgID(FlatBufferBuilder builder, int msgID) { builder.addInt(0, msgID, 1); }public static void addUsername(FlatBufferBuilder builder, int usernameOffset) { builder.addOffset(1, usernameOffset, 0); }public static void addPassword(FlatBufferBuilder builder, int passwordOffset) { builder.addOffset(2, passwordOffset, 0); }public static void addTime(FlatBufferBuilder builder, long time) { builder.addLong(3, time, 0); }public static int endLoginRequest(FlatBufferBuilder builder) {int o = builder.endObject();return o;}
};

// automatically generated, do not modifypackage com.dc.gameserver.genflat;import com.google.flatbuffers.FlatBufferBuilder;
import com.google.flatbuffers.Table;import java.nio.ByteBuffer;
import java.nio.ByteOrder;///public class LoginResponse extends Table {public static LoginResponse getRootAsLoginResponse(ByteBuffer _bb) { return getRootAsLoginResponse(_bb, new LoginResponse()); }public static LoginResponse getRootAsLoginResponse(ByteBuffer _bb, LoginResponse obj) { _bb.order(ByteOrder.LITTLE_ENDIAN); return (obj.__init(_bb.getInt(_bb.position()) + _bb.position(), _bb)); }public LoginResponse __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; return this; }public int msgID() { int o = __offset(4); return o != 0 ? bb.getInt(o + bb_pos) : 2; }public long time() { int o = __offset(6); return o != 0 ? bb.getLong(o + bb_pos) : 0; }public String uid() { int o = __offset(8); return o != 0 ? __string(o + bb_pos) : null; }public ByteBuffer uidAsByteBuffer() { return __vector_as_bytebuffer(8, 1); }public static int createLoginResponse(FlatBufferBuilder builder,int msgID,long time,int uid) {builder.startObject(3);LoginResponse.addTime(builder, time);LoginResponse.addUid(builder, uid);LoginResponse.addMsgID(builder, msgID);return LoginResponse.endLoginResponse(builder);}public static void startLoginResponse(FlatBufferBuilder builder) { builder.startObject(3); }public static void addMsgID(FlatBufferBuilder builder, int msgID) { builder.addInt(0, msgID, 2); }public static void addTime(FlatBufferBuilder builder, long time) { builder.addLong(1, time, 0); }public static void addUid(FlatBufferBuilder builder, int uidOffset) { builder.addOffset(2, uidOffset, 0); }public static int endLoginResponse(FlatBufferBuilder builder) {int o = builder.endObject();return o;}
};

消息设计原则除了基础的游戏数据会有一个消息ID。

获取生成Table消息ID可以这样：

 LoginResponse.getRootAsLoginResponse(ByteBuffer.allocate(4)).msgID();

修改了下源码(Table)，避免new一个ByteBuffer，可以这样

  // Look up a field in the vtable, return an offset into the object, or 0 if the field is not// present.protected int __offset(int vtable_offset) {if (bb == null) return 0; // get msgID  ,ignore allocate ByteBufferint vtable = bb_pos - bb.getInt(bb_pos);return vtable_offset < bb.getShort(vtable) ? bb.getShort(vtable + vtable_offset) : 0;}

new LoginResponse().msgID();

flatbuffer中有对默认的数值填充，将会不对其存储！。如没有默认值的字段都为0，不管基础数据类型还是string.;存在默认值如id:int=1;在填充数据value==1时，不会被存储。

反正默认值不被存储就对了，详见代码Table;当然可以强制进行存储，builder.setForcexx(true);

netty只负责网络传输。解析网络字节码就对了，根据协议包长+消息体（ID+游戏操作数据）。

针对java，采用多态的方式进行处理对应的消息体。

  static final IController game_controllers[] = new IController[2];

存储消息处理类的引用。

Controller接口设计：

/*** 基于flatBuffers 结构数据传输** @param data   cast subclass of table .* @param player game session* @throws Exception*/void DispatchFlatBuffer(final byte[] data, final PlayerInstance player) throws Exception;

实现类：

/** Copyright (c) 2015.* 游戏服务器核心代码编写人石头哥哥拥有使用权* 最终使用解释权归创心科技所有* 联系方式：E-mail:13638363871@163.com ;* 个人博客主页：http://my.oschina.net/chenleijava* powered by 石头哥哥*/package com.dc.gameserver.servercore.controller.testflatbuffercontroller;import com.dc.gameserver.genflat.LoginRequest;
import com.dc.gameserver.genflat.LoginResponse;
import com.dc.gameserver.model.character.PlayerInstance;
import com.dc.gameserver.servercore.controller.abstractController.AbstractController;
import com.google.flatbuffers.FlatBufferBuilder;
import com.google.protobuf.MessageLite;
import org.springframework.stereotype.Service;import java.nio.ByteBuffer;
import java.util.UUID;/*** @author 石头哥哥*         </P>*         Date:   2015/6/1*         </P>*         Time:   14:36*         </P>*         Package: dcServer-parent*         </P>*         <p/>*         注解： 测试flatbuf 转化到游戏逻辑处理*/
@Service
public class TestFlatBufferController extends AbstractController {/*** spring 容器初始化 加载并初始化相应控制器处理句柄* 非spring环境下 可以采用静态的初始化方案*/@Overridepublic void PostConstruct() {game_controllers[new LoginRequest().msgID()] = this;}/*** messageLite数据结构体分发** @param messageLite 数据载体* @param player      active object* @throws Exception 注意messageLite应该递交给GC直接处理  ，set null*/@Override@Deprecatedpublic void DispatchMessageLit(MessageLite messageLite, PlayerInstance player) throws Exception {}/*** 基于flatBuffers 结构数据传输** @param data   cast subclass of table .         msgID + 游戏数据（可反序列化为flatbuffers Table 子类 这里如LoginRequest）* @param player game session* @throws Exception*/@Overridepublic void DispatchFlatBuffer(byte[] data, PlayerInstance player) throws Exception {//4 为消息ID 所占用的位置LoginRequest login = LoginRequest.getRootAsLoginRequest(ByteBuffer.wrap(data, 4, data.length - 4));String username = login.username();String password = login.password();// do something// get msgIDint msgID = new LoginResponse().msgID();FlatBufferBuilder builder = new FlatBufferBuilder(8);builder.finish(LoginResponse.createLoginResponse(builder, msgID, System.currentTimeMillis(), builder.createString(UUID.randomUUID().toString())));wrappedBufferInt(msgID, builder);}public static void main(String[] args) {//builder data  and finish itint msgID = new LoginResponse().msgID();FlatBufferBuilder builder = new FlatBufferBuilder(8);builder.finish(LoginResponse.createLoginResponse(builder, msgID, System.currentTimeMillis(), builder.createString(UUID.randomUUID().toString())));wrappedBufferInt(msgID, builder);}}

由于flatbuf相对protobuffer 体积较小  在cocos2dx中应用 相对较为方便。  目前已经有一套完整的应用解决方案思路(前后端代码生成器)。欢迎交流！