ProtoBuf和Netty的简单使用

先看工程路径，如下图

1.pom.xml:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>netty-demo</groupId>
    <artifactId>com.kingdee</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <spring.version>3.2.5.RELEASE</spring.version>
        <spring.rabbit.version>1.3.5.RELEASE</spring.rabbit.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/io.netty/netty-all -->
        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.0.23.Final</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/log4j/log4j -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/commons-logging/commons-logging -->
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.1.1</version>
        </dependency>

        <dependency>
            <groupId>com.google.protobuf</groupId>
            <artifactId>protobuf-java</artifactId>
            <version>3.0.0</version>
        </dependency>
    </dependencies>
</project>

2.msg.proto,把它转换成java代码,再拷贝到对应的包下,利用proto.exe工具生成

mgs.proto:

package com.netty.demo;
message Client {  
    required string head = 1;  
    required string body = 2;  
}

message Server {
    required int32 code=1;
    required string message=2;
}

 

3.客户端代码：

Client.java:

package com.netty.demo.client;

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 Client {
    public static String host = "127.0.0.1";
    public static int port = 8787;

    public static void main(String[] args) {
        EventLoopGroup worker = new NioEventLoopGroup();
        Bootstrap b = new Bootstrap();
        b.group(worker);
        b.channel(NioSocketChannel.class);
        b.handler(new ClientInitializer());
        try {
            ChannelFuture f = b.connect(host, port).sync();
            f.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            
            e.printStackTrace();
        } finally {
            worker.shutdownGracefully();
        }

    }
}

ClientHandler.java(处理客户端消息发送和收到服务端消息的处理,但一般情况下是不会在这里写发送消息的逻辑的，只是为了写demo，所以把发消息写在这里面)

package com.netty.demo.client;

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

import com.google.protobuf.Message;
import com.netty.demo.Msg;

public class ClientHandler extends SimpleChannelInboundHandler<Message> {

    /**
     * 
     */
    protected void channelRead0(ChannelHandlerContext ctx, Message msg) throws Exception {
        
        System.out.println("Server say : " + msg.toString());
    }

    /**
     * 
     */
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("Client active ");
        Msg.Client msg = Msg.Client.newBuilder().setHead("Content-Type:application/json;charset=UTF-8").setBody("hello world!").build();
        ctx.writeAndFlush(msg);
        super.channelActive(ctx);
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("Client close ");
        super.channelInactive(ctx);
    }

}

ClientInitializer.java（初始化Chanel，如解码，加密等）

package com.netty.demo.client;

import com.netty.demo.Msg;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.codec.LengthFieldPrepender;
import io.netty.handler.codec.protobuf.ProtobufDecoder;
import io.netty.handler.codec.protobuf.ProtobufEncoder;

public class ClientInitializer extends ChannelInitializer<SocketChannel> {

    protected void initChannel(SocketChannel ch) throws Exception {
        // decoded
        ch.pipeline().addLast(new LengthFieldBasedFrameDecoder(1024, 0, 4, 0, 4));
        //这里是收到服务端发过来的消息,所以是对服务端的response解码
        ch.pipeline().addLast(new ProtobufDecoder(Msg.Server.getDefaultInstance()));
        // encoded
        ch.pipeline().addLast(new LengthFieldPrepender(4));
        ch.pipeline().addLast(new ProtobufEncoder());
        // 注册handler
        ch.pipeline().addLast(new ClientHandler());
    }

}

4.Server端代码：

Server.java

package com.netty.demo.server;

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

public class Server {
    private static int port = 8787;
    public static void main(String[] args) {
        EventLoopGroup boss = new NioEventLoopGroup();
        EventLoopGroup worker = new NioEventLoopGroup();
        ServerBootstrap server = new ServerBootstrap();
        server.group(boss, worker);
        server.channel(NioServerSocketChannel.class);
        server.childHandler(new ServerInitializer());
        server.option(ChannelOption.SO_BACKLOG, 128);
        server.childOption(ChannelOption.SO_KEEPALIVE, true);
        
        try {
            //绑定端口 同步等待成功
            ChannelFuture f = server.bind(port).sync();
            //等待服务端监听端口关闭
            f.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            
            e.printStackTrace();
        } finally {
            worker.shutdownGracefully();
            boss.shutdownGracefully();
        }
    }
}

ServerHandler.java:

package com.netty.demo.server;

import java.net.InetAddress;

import com.google.protobuf.Message;
import com.netty.demo.Msg;
import com.netty.demo.Msg.Client;

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

/**
 * 处理客户端连接时的handler
 * 
 * @author shizhengchao32677
 * 
 */
public class ServerHandler extends SimpleChannelInboundHandler<Message> {

    /**
     * 收到客户端发过来的消息
     */
    protected void channelRead0(ChannelHandlerContext ctx, Message msg) throws Exception {
        // 收到消息直接打印输出
        System.out.println(msg.getClass());
        Msg.Server response = null;
        if(msg instanceof Msg.Client) {
            Msg.Client clientMsg = (Client) msg;
            System.out.println(ctx.channel().remoteAddress() + " Say : " + clientMsg.getBody());
            response = Msg.Server.newBuilder().setCode(0).setMessage("Received client message success").build();
        } else {
            response = Msg.Server.newBuilder().setCode(-1).setMessage("client message is illegal").build();
            System.out.println("client message is illegal");
        }
        // 返回客户端消息 - 我已经接收到了你的消息
        ctx.writeAndFlush(response);
    }

    /*
     * 覆盖 channelActive 方法 在channel被启用的时候触发 (在建立连接的时候)
     */
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("RamoteAddress : " + ctx.channel().remoteAddress() + " active !");
        String welcome = "Welcome to " + InetAddress.getLocalHost().getHostName() + " service!";
        Msg.Server response = Msg.Server.newBuilder().setCode(101).setMessage(welcome).build();
        ctx.writeAndFlush(response);
        super.channelActive(ctx);
    }

}

ServerInitializer.java

package com.netty.demo.server;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.codec.LengthFieldPrepender;
import io.netty.handler.codec.protobuf.ProtobufDecoder;
import io.netty.handler.codec.protobuf.ProtobufEncoder;

import com.netty.demo.Msg;

public class ServerInitializer extends ChannelInitializer<SocketChannel> {

    protected void initChannel(SocketChannel ch) throws Exception {
        // decoded
        ch.pipeline().addLast(new LengthFieldBasedFrameDecoder(1024, 0, 4, 0, 4));
        //解码客户端发过来的消息
        ch.pipeline().addLast(new ProtobufDecoder(Msg.Client.getDefaultInstance()));
        // encoded
        ch.pipeline().addLast(new LengthFieldPrepender(4));
        ch.pipeline().addLast(new ProtobufEncoder());
        // 注册handler
        ch.pipeline().addLast(new ServerHandler());
    }

}

 

运行Server.java和Client.java:

Server输出：

RamoteAddress : /127.0.0.1:59693 active !
class com.netty.demo.Msg$Client
/127.0.0.1:59693 Say : hello world!



Clientl输出：

Client active 
Server say : code: 101
message: "Welcome to H4UOJJQSF23HQ91 service!"

Server say : code: 0
message: "Received client message success"