Netty中集成Protobuf实现Java对象数据传递

在上面两篇博客基础上，对于Socket搭建服务端和客户端进行通信以及

在Java中Protobuf的使用已经有了初步的理解。

那么怎样使用Netty进行服务端和客户端的通信时使用protobuf进行数据传递。

注：

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实现

在src下新建protobuf目录，目录下新建Person.prpto描述文件

syntax = "proto3";

package com.badao.protobuf;

option optimize_for =SPEED;
option java_package = "com.badao.NettyProtobuf";
option java_outer_classname = "BadaoDataInfo";

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

具体的讲解可以见上面的博客。

然后在src/main/java下新建包com.badao.NettyProtobuf

打开终端Ternimal，使用protoc进行编译代码

protoc --java_out=src/main/java src/protobuf/Person.proto

然后就会在上面NettyProtobuf包下生成BadaoDataInfo类

上面具体的流程与讲解参照上面的博客。

然后新建服务端类NettyProtobufServer

package com.badao.NettyProtobuf;

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;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;

public class NettyProtobufServer {
    public static void main(String[] args) throws  Exception
    {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try{
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap.group(bossGroup,workerGroup).channel(NioServerSocketChannel.class)
                    .handler(new LoggingHandler(LogLevel.INFO))
                    .childHandler(new NettyProtobufInitializer());
            //绑定端口
            ChannelFuture channelFuture = serverBootstrap.bind(70).sync();
            channelFuture.channel().closeFuture().sync();
        }finally {
            //关闭事件组
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

其中用到了自定义的初始化器NettyProtoInitilizer

package com.badao.NettyProtobuf;

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 NettyProtobufInitializer extends ChannelInitializer<SocketChannel> {
    @Override
    protected void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();

        pipeline.addLast(new ProtobufVarint32FrameDecoder());
        pipeline.addLast(new ProtobufDecoder(BadaoDataInfo.Person.getDefaultInstance()));
        pipeline.addLast(new ProtobufVarint32LengthFieldPrepender());
        pipeline.addLast(new ProtobufEncoder());

        pipeline.addLast(new NettyProtobufHandler());
    }
}

注意这里不同的是添加的处理器是Netty自带的关于Protobuf的解码编码的处理器。

其中Decode处理器的参数就是上面生成的代码的默认的实例。

然后最后又添加了自定义的处理器NettyProtobufHandler

package com.badao.NettyProtobuf;

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

public class NettyProtobufHandler extends SimpleChannelInboundHandler<BadaoDataInfo.Person> {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, BadaoDataInfo.Person msg) throws Exception {
        System.out.println(msg.getName());
        System.out.println(msg.getAge());
        System.out.println(msg.getAddress());
    }
}

自定义处理器中在收到发送的消息时将消息进行输出，这里这里在继承SimpleChannelInboundHandler

的泛型就是上面生成的类。

然后新建客户端类

package com.badao.NettyProtobuf;

import io.netty.bootstrap.Bootstrap;
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 NettyProtobufClient {
    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 NettyProtoBufClientInitializer());
            //绑定端口
            ChannelFuture channelFuture = bootstrap.connect("localhost", 70);
            channelFuture.channel().closeFuture().sync();
        } finally {
            //关闭事件组
            eventLoopGroup.shutdownGracefully();

        }
    }
}

编写其用到的初始化器

package com.badao.NettyProtobuf;

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 NettyProtoBufClientInitializer extends ChannelInitializer<SocketChannel> {
    @Override
    protected void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();

        pipeline.addLast(new ProtobufVarint32FrameDecoder());
        pipeline.addLast(new ProtobufDecoder(BadaoDataInfo.Person.getDefaultInstance()));
        pipeline.addLast(new ProtobufVarint32LengthFieldPrepender());
        pipeline.addLast(new ProtobufEncoder());

        pipeline.addLast(new NettyProtobufClientHandler());
    }
}

和服务端的初始化器用到的处理器一致，最后也要有自定义的处理器

package com.badao.NettyProtobuf;

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

public class NettyProtobufClientHandler extends SimpleChannelInboundHandler<BadaoDataInfo.Person> {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, BadaoDataInfo.Person msg) throws Exception {

    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        BadaoDataInfo.Person person = BadaoDataInfo.Person.newBuilder()
                .setName("公众号:霸道的程序猿")
                .setAge(100)
                .setAddress("中国").build();
        ctx.channel().writeAndFlush(person);
    }
}

在与服务端建立连接即通道激活的回调方法中向服务端发送数据。

然后运行服务端的main方法再运行客户端的main方法。