Netty中Protobuf多协议消息支撑

先定义.proto文件，其中定义一个枚举DateType标识不同的消息类别，然后oneof定义Mymessage中的dataBody只能是Person、Dog、Cat中的一种。然后使用protobuf编译器编译，编译命令：protoc --java_out=src/main/java src/protobuf/Person.proto

syntax = "proto2";

package com.wq.protobuf;

option optimize_for = SPEED;
option java_package = "com.wq.nettyproto";
option java_outer_classname = "MyDataInfo";

message MyMessage{
    enum DateType{
        PersonType = 1;
        DogType = 2;
        CatType = 3;
    }
    required DateType data_type= 1;
    oneof dataBody{
        Person person = 2;
        Dog dog = 3;
        Cat cat = 4;
    }

}

message Person{
    optional string name = 1;
    optional int32 age = 2;
    optional string address = 3;
}
message Dog{
    optional string name = 1;
    optional int32 age = 2;
}

message Cat{
    optional string name = 1;
    optional string city = 2;
}

接下来是netty服务端代码：其中handler中的channelRead0中的参数为MyDataInfo.MyMessage类型，然后可以根据其中的msg.getDataType()来判断传过来的是Person、Dog、Cat然后进行处理。

package com.wq.nettyproto;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;

public class MyServer {
    public static void main(String[] args) {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try{
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap.group(bossGroup,workerGroup).
                    channel(NioServerSocketChannel.class).
                    childHandler(new MyServerInitializer());
            ChannelFuture channelFuture = serverBootstrap.bind(8899).sync();
            channelFuture.channel().closeFuture().sync();
        }catch(Exception e){
            e.printStackTrace();
        }finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

package com.wq.nettyproto;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.protobuf.ProtobufDecoder;
import io.netty.handler.codec.protobuf.ProtobufEncoder;
import io.netty.handler.codec.protobuf.ProtobufVarint32FrameDecoder;
import io.netty.handler.codec.protobuf.ProtobufVarint32LengthFieldPrepender;

public class MyServerInitializer extends ChannelInitializer {
    @Override
    protected void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();
        pipeline.addLast(new ProtobufVarint32FrameDecoder());
        pipeline.addLast(new ProtobufDecoder(MyDataInfo.MyMessage.getDefaultInstance()));
        pipeline.addLast(new ProtobufVarint32LengthFieldPrepender());
        pipeline.addLast(new ProtobufEncoder());
        pipeline.addLast(new MyServerHandler());

    }
}

package com.wq.nettyproto;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;

public class MyServerHandler extends SimpleChannelInboundHandler {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, MyDataInfo.MyMessage msg) throws Exception {
       MyDataInfo.MyMessage.DateType dateType =  msg.getDataType();
        if(dateType==MyDataInfo.MyMessage.DateType.PersonType){
            MyDataInfo.Person person = msg.getPerson();
            System.out.println(person.getName());
            System.out.println(person.getAge());
            System.out.println(person.getAddress());
        }else  if(dateType==MyDataInfo.MyMessage.DateType.DogType){
            MyDataInfo.Dog dog = msg.getDog();
            System.out.println(dog.getName());
            System.out.println(dog.getAge());
        }else  if(dateType==MyDataInfo.MyMessage.DateType.CatType){
            MyDataInfo.Cat cat = msg.getCat();
            System.out.println(cat.getName());
            System.out.println(cat.getCity());
        }

    }
}

接下来是客户端：其中在handler中的channelActive中随机生成Person、Dog、Cat然后传给服务端。

package com.wq.nettyproto;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;


public class MyClient {
    public static void main(String[] args) throws Exception{
        EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
        try{
            Bootstrap bootstrap = new Bootstrap();
            bootstrap.group(eventLoopGroup).channel(NioSocketChannel.class).handler(new MyClientInitializer());
            ChannelFuture channelFuture = bootstrap.connect("localhost",8899).sync();
            channelFuture.channel().closeFuture().sync();
        }catch(Exception e){
            e.printStackTrace();
        }finally {
            eventLoopGroup.shutdownGracefully();
        }
    }
}

package com.wq.nettyproto;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.protobuf.ProtobufDecoder;
import io.netty.handler.codec.protobuf.ProtobufEncoder;
import io.netty.handler.codec.protobuf.ProtobufVarint32FrameDecoder;
import io.netty.handler.codec.protobuf.ProtobufVarint32LengthFieldPrepender;

public class MyClientInitializer extends ChannelInitializer {
    @Override
    protected void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();
        pipeline.addLast(new ProtobufVarint32FrameDecoder());
        pipeline.addLast(new ProtobufDecoder(MyDataInfo.Person.getDefaultInstance()));
        pipeline.addLast(new ProtobufVarint32LengthFieldPrepender());
        pipeline.addLast(new ProtobufEncoder());
        pipeline.addLast(new MyClientHandler());
    }
}

package com.wq.nettyproto;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;

import java.util.Random;

public class MyClientHandler extends SimpleChannelInboundHandler {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, MyDataInfo.MyMessage msg) throws Exception {

    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {

        int randomInt = new Random().nextInt(3);
        MyDataInfo.MyMessage.Builder myMessage = null;
        if(randomInt==0){
            myMessage = MyDataInfo.MyMessage.newBuilder().
                    setDataType(MyDataInfo.MyMessage.DateType.PersonType).
                    setPerson(MyDataInfo.Person.newBuilder().
                            setName("王强").
                            setAge(30).
                            setAddress("郑州").build());
        }else if (randomInt==1){
            myMessage = MyDataInfo.MyMessage.newBuilder().
                    setDataType(MyDataInfo.MyMessage.DateType.DogType).setDog(MyDataInfo.Dog.newBuilder().setName("tomDog").setAge(2).build());
        }else{
            myMessage = MyDataInfo.MyMessage.newBuilder().
                    setDataType(MyDataInfo.MyMessage.DateType.CatType).setCat(MyDataInfo.Cat.newBuilder().setName("hellokity").setCity("香港迪士尼").build());
        }
        ctx.channel().writeAndFlush(myMessage);
    }
}