netty4与protocol buffer结合简易教程

各项目之间通常使用二进制进行通讯，占用带宽小、处理速度快~

感谢netty作者Trustin Lee。让netty天生支持protocol buffer。

本实例使用netty4+protobuf-2.5.0。在win7下运行。而且如果已经安装jdk和maven。

1、下载并解压protoc-2.5.0-win32.zip和protobuf-2.5.0.zip

2、到protobuf-2.5.0.zip安装文件夹protobuf-2.5.0\java下，运行maven命令：mvn package jar:jar，将生成target\protobuf-java-2.5.0.jar

3、定义proto文件test.proto：

package domain;



option java_package = "com.server.domain";



message TestPro {

  required string test = 1;

}

4、将第2部的jar包复制到java文件存放文件夹下，然后执行以下命令，生成java文件：

protoc-2.5.0-win32.zip安装文件夹\protoc.exe --java_out=java文件存放文件夹 proto定义文件文件夹\test.proto

5、将生成的protobuf-java-2.5.0.jar和netty4的jar包放到项目的classpath中，并将第4部生成的java文件放到项目的对应路径下。

6、编写Server端代码

1）、编写handler类：

import io.netty.channel.ChannelHandlerContext;

import io.netty.channel.SimpleChannelInboundHandler;



public class ServerHandler extends SimpleChannelInboundHandler<Test.TestPro> {

@Override

public void channelRead0(ChannelHandlerContext ctx, Test.TestPro msg) throws Exception {

System.out.println("server:" + "channelRead:" + msg.getTest());



Test.TestPro.Builder builder = Test.TestPro.newBuilder();

builder.setTest("Received your message !");

ctx.writeAndFlush(builder.build());

}

}

2）、注冊服务，绑定port：

import io.netty.bootstrap.ServerBootstrap;

import io.netty.channel.Channel;

import io.netty.channel.ChannelFuture;

import io.netty.channel.ChannelInitializer;

import io.netty.channel.ChannelOption;

import io.netty.channel.EventLoopGroup;

import io.netty.channel.nio.NioEventLoopGroup;

import io.netty.channel.socket.nio.NioServerSocketChannel;

import io.netty.handler.codec.protobuf.ProtobufDecoder;

import io.netty.handler.codec.protobuf.ProtobufEncoder;



public class Server {



public static void main(String[] args) {

EventLoopGroup bossEventLoopGroup = new NioEventLoopGroup();

EventLoopGroup workerEventLoopGroup = new NioEventLoopGroup();

try {

ServerBootstrap serverBootstrap = new ServerBootstrap();

serverBootstrap.group(bossEventLoopGroup, workerEventLoopGroup);

serverBootstrap.channel(NioServerSocketChannel.class);

serverBootstrap.childHandler(new ChannelInitializer<Channel>() {

@Override

protected void initChannel(Channel ch) throws Exception {

ch.pipeline().addLast("encoder", new ProtobufEncoder());

ch.pipeline().addLast("decoder", new ProtobufDecoder(Test.TestPro.getDefaultInstance()));

ch.pipeline().addLast("handler", new ServerHandler());

};

});

serverBootstrap.childOption(ChannelOption.SO_KEEPALIVE, true);

ChannelFuture channelFuture = serverBootstrap.bind(8888).sync();

channelFuture.channel().closeFuture().sync();

} catch (Exception e) {

e.printStackTrace();

} finally {

bossEventLoopGroup.shutdownGracefully();

workerEventLoopGroup.shutdownGracefully();

}

}

}

7、编写Client端代码

1）、定义Client端的handler类：

import io.netty.channel.ChannelHandlerContext;

import io.netty.channel.SimpleChannelInboundHandler;



public class ClientHandler extends SimpleChannelInboundHandler<Test.TestPro> {



@Override

protected void channelRead0(ChannelHandlerContext ctx, Test.TestPro msg) throws Exception {

System.out.println("client:" + "channelRead:" + msg.getTest());

}

}

2）、建立Client端到Server端的连接

import java.io.BufferedReader;

import java.io.InputStreamReader;



import io.netty.bootstrap.Bootstrap;

import io.netty.channel.Channel;

import io.netty.channel.ChannelInitializer;

import io.netty.channel.EventLoopGroup;

import io.netty.channel.nio.NioEventLoopGroup;

import io.netty.channel.socket.nio.NioSocketChannel;

import io.netty.handler.codec.protobuf.ProtobufDecoder;

import io.netty.handler.codec.protobuf.ProtobufEncoder;

import io.netty.handler.codec.string.StringDecoder;

import io.netty.handler.codec.string.StringEncoder;



public class Client {



public static void main(String[] args) {

EventLoopGroup eventLoopGroup = new NioEventLoopGroup();

try {

Bootstrap bootstrap = new Bootstrap();

bootstrap.group(eventLoopGroup);

bootstrap.channel(NioSocketChannel.class);

bootstrap.handler(new ChannelInitializer<Channel>() {

@Override

protected void initChannel(Channel ch) throws Exception {

ch.pipeline().addLast("encoder", new ProtobufEncoder());

ch.pipeline().addLast("decoder", new ProtobufDecoder(Test.TestPro.getDefaultInstance()));

ch.pipeline().addLast("handler", new ClientHandler());

};

});



Channel ch = bootstrap.connect("127.0.0.1", 8888).sync().channel();



// 控制台输入

BufferedReader in = new BufferedReader(new InputStreamReader(System.in));

for (;;) {

String line = in.readLine();

if (line == null || "".equals(line)) {

continue;

}

Test.TestPro.Builder builder = Test.TestPro.newBuilder();

builder.setTest(line);

ch.writeAndFlush(builder.build());

}

} catch (Exception e) {

e.printStackTrace();

} finally {

eventLoopGroup.shutdownGracefully();

}

}

}

新手教程，欢迎拍砖。

推荐其它參考教程：protocol与netty结合的资料http://blog.csdn.net/goldenfish1919/article/details/6719276