Netty中集成Protobuf实现Java对象数据传递

深藏阁楼爱情的钟 2023-10-05 07:29 2阅读 0赞

## 场景 ##

Netty的Socket编程详解-搭建服务端与客户端并进行数据传输：

[https://blog.csdn.net/BADAO\_LIUMANG\_QIZHI/article/details/108615023][https_blog.csdn.net_BADAO_LIUMANG_QIZHI_article_details_108615023]

ProtoBuf的介绍以及在Java中使用protobuf将对象进行序列化与反序列化：

[https://blog.csdn.net/BADAO\_LIUMANG\_QIZHI/article/details/108667427][https_blog.csdn.net_BADAO_LIUMANG_QIZHI_article_details_108667427]

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：

博客：  
[https://blog.csdn.net/badao\_liumang\_qizhi][https_blog.csdn.net_badao_liumang_qizhi]  
关注公众号  
霸道的程序猿  
获取编程相关电子书、教程推送与免费下载。

## 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

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。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70][]

### 示例代码下载 ###

[https://download.csdn.net/download/BADAO\_LIUMANG\_QIZHI/12863005][https_download.csdn.net_download_BADAO_LIUMANG_QIZHI_12863005]

[https_blog.csdn.net_BADAO_LIUMANG_QIZHI_article_details_108615023]: https://blog.csdn.net/BADAO_LIUMANG_QIZHI/article/details/108615023
[https_blog.csdn.net_BADAO_LIUMANG_QIZHI_article_details_108667427]: https://blog.csdn.net/BADAO_LIUMANG_QIZHI/article/details/108667427
[https_blog.csdn.net_badao_liumang_qizhi]: https://blog.csdn.net/badao_liumang_qizhi
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200919114600276.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk=,size_16,color_FFFFFF,t_70
[https_download.csdn.net_download_BADAO_LIUMANG_QIZHI_12863005]: https://download.csdn.net/download/BADAO_LIUMANG_QIZHI/12863005