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
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
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
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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。
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