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Netty結(jié)合Protobuf進(jìn)行編解碼的方法

更新時(shí)間：2021年06月25日 17:34:34 作者：xiah_jp

這篇文章主要介紹了Netty結(jié)合Protobuf進(jìn)行編解碼,通過(guò)文檔表述和代碼實(shí)例充分說(shuō)明了如何進(jìn)行使用和操作,需要的朋友可以參考下

一般在使用netty時(shí)，數(shù)據(jù)傳輸?shù)臅r(shí)候都會(huì)選擇對(duì)傳輸?shù)臄?shù)據(jù)進(jìn)行編解碼，編碼后的數(shù)據(jù)變小，有利于在有限的帶寬下傳輸更多的數(shù)據(jù)。

由于java本身序列化的缺點(diǎn)較多（無(wú)法跨語(yǔ)言，序列化后的碼流太大，序列化的性能太低等），業(yè)界主流的編解碼框架主要有如下三個(gè):

Google的Protobuf
Facebook的Thrift
JBoss的Marshalling

今天我們簡(jiǎn)單介紹一下Netty結(jié)合google的Protobuf框架進(jìn)行數(shù)據(jù)的編解碼。

1. 什么是Protobuf？

Protobuf全稱(chēng)是Google Protocol Buffers, 它是谷歌公司開(kāi)源的一個(gè)序列化框架。

它將數(shù)據(jù)結(jié)構(gòu)以.proto文件進(jìn)行描述，通過(guò)代碼生成工具可以生成對(duì)應(yīng)數(shù)據(jù)結(jié)構(gòu)的POJO對(duì)象和Protobuf相關(guān)的方法和屬性。

它的特點(diǎn)如下：

結(jié)構(gòu)化數(shù)據(jù)存儲(chǔ)格式
高效的編解碼性能
語(yǔ)言無(wú)關(guān)、平臺(tái)無(wú)關(guān)、擴(kuò)展性好
官方支持多個(gè)語(yǔ)言（java，c++，python，c#等）

2. 下載安裝

Protobuf已經(jīng)托管在github上，可以在release頁(yè)面下載，本案例使用的是v3.6（要下載后綴為-win32.zip的）。

下載后，將壓縮包進(jìn)行解壓。這里主要用到bin目錄下的protoc.exe。

3. 定義好proto文件

SubscribeReq.proto

// 區(qū)分不同的protobuf版本，必須有
syntax = "proto2";
 
package netty;
// 生成的目標(biāo)類(lèi)的包路徑
option java_package = "cn.ddlover.nettystudy.protobuf";
// 生成的目標(biāo)類(lèi)的名字
option java_outer_classname = "SubscribeReqProto";
 
message SubscribeReq{
    required int32 subReqID = 1;
    required string userName = 2;
    required string productName = 3;
    repeated string address = 4;
}

SubscribeResp.proto

syntax = "proto2";
package netty;
 
option java_package = "cn.ddlover.nettystudy.protobuf";
option java_outer_classname = "SubscribeRespProto";
 
message SubscribeResp{
    required int32 subReqID = 1;
    required int32 respCode = 2;
    required string desc = 3;
}

此時(shí)項(xiàng)目結(jié)構(gòu)如下

重點(diǎn)關(guān)注一下兩個(gè)proto文件的位置，是位于項(xiàng)目的根路徑下

4. 分別執(zhí)行以下命令

D:\xhb\protoc-3.6.1-win32\bin\protoc.exe --java_out=.\src\main\java SubscribeResp.proto

D:\xhb\protoc-3.6.1-win32\bin\protoc.exe --java_out=.\src\main\java SubscribeReq.proto

這里需要把protoc.exe的位置換成自己的， --java_out命令設(shè)置的是proto文件中java_package指令的父目錄。

5. 此時(shí)項(xiàng)目結(jié)構(gòu)如下

下面開(kāi)始代碼方面的開(kāi)發(fā)，

1. 先貼一波maven的配置

<?xml version="1.0" encoding="UTF-8"?>
<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>cn.ddlover</groupId>
    <artifactId>nettystudy</artifactId>
    <version>1.0-SNAPSHOT</version>
 
 
    <properties>
        <java.version>1.8</java.version>
    </properties>
 
    <dependencies>
        <!-- https://mvnrepository.com/artifact/io.netty/netty-all -->
        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.1.33.Final</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/com.google.protobuf/protobuf-java -->
        <dependency>
            <groupId>com.google.protobuf</groupId>
            <artifactId>protobuf-java</artifactId>
            <version>3.6.1</version>
        </dependency>
 
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.4</version>
        </dependency>
    </dependencies>
</project>

2. 這里貼上完整代碼的項(xiàng)目結(jié)構(gòu)

3. SubReqServer.java

 
import cn.ddlover.nettystudy.handler.SubReqServerHandler;
import cn.ddlover.nettystudy.protobuf.SubscribeReqProto;
import io.netty.bootstrap.ServerBootstrap;
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.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
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;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
 
/**
 * Protobuf版本圖書(shū)訂購(gòu)代碼
 */
public class SubReqServer {
    private static final int PORT = 8080;
 
    public static void main(String[] args) {
        bind(PORT);
    }
 
    private static void bind(int port) {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
 
        ServerBootstrap b = new ServerBootstrap();
        try {
            b.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .option(ChannelOption.SO_BACKLOG, 100)
                    .handler(new LoggingHandler(LogLevel.INFO))
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel socketChannel) throws Exception {
                            // 半包處理
                            socketChannel.pipeline().addLast(new ProtobufVarint32FrameDecoder());
                            socketChannel.pipeline().addLast(new ProtobufDecoder(SubscribeReqProto.SubscribeReq.getDefaultInstance()));
                            socketChannel.pipeline().addLast(new ProtobufVarint32LengthFieldPrepender());
                            socketChannel.pipeline().addLast(new ProtobufEncoder());
                            socketChannel.pipeline().addLast(new SubReqServerHandler());
                        }
                    });
            ChannelFuture future = b.bind(port).sync();
            future.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

4. SubReqServerHandler.java

import cn.ddlover.nettystudy.protobuf.SubscribeReqProto;
import cn.ddlover.nettystudy.protobuf.SubscribeRespProto;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
 
public class SubReqServerHandler extends ChannelInboundHandlerAdapter {
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        SubscribeReqProto.SubscribeReq req = (SubscribeReqProto.SubscribeReq)msg;
 
        if ("張三".equals(req.getUserName())) {
            System.out.println("Server accept clietn subscribe req : ["+req.toString()+"]");
            ctx.writeAndFlush(resp(req.getSubReqID()));
        }
    }
 
    private SubscribeRespProto.SubscribeResp resp(int subReqID) {
        SubscribeRespProto.SubscribeResp.Builder builder = SubscribeRespProto.SubscribeResp.newBuilder();
        builder.setSubReqID(subReqID);
        builder.setRespCode(0);
        builder.setDesc("netty書(shū)籍下單成功，3天后將會(huì)送到你的住處");
        return builder. build();
    }
 
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }
}

5. SubReqClient.java

import cn.ddlover.nettystudy.handler.SubReqClientHandler;
import cn.ddlover.nettystudy.protobuf.SubscribeRespProto;
import io.netty.bootstrap.Bootstrap;
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.SocketChannel;
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.protobuf.ProtobufVarint32FrameDecoder;
import io.netty.handler.codec.protobuf.ProtobufVarint32LengthFieldPrepender;
 
public class SubReqClient {
    private static final String HOST = "localhost";
    private static final int PORT = 8080;
 
    public static void main(String[] args) {
        connect(HOST, PORT);
    }
 
    private static void connect(String host, int port) {
        EventLoopGroup group = new NioEventLoopGroup();
 
        Bootstrap b = new Bootstrap();
        try {
            b.group(group).channel(NioSocketChannel.class)
                    .option(ChannelOption.TCP_NODELAY, true)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel socketChannel) throws Exception {
 
                            // 半包處理
                            socketChannel.pipeline().addLast(new ProtobufVarint32FrameDecoder());
                            socketChannel.pipeline().addLast(new ProtobufDecoder(SubscribeRespProto.SubscribeResp.getDefaultInstance()));
                            socketChannel.pipeline().addLast(new ProtobufVarint32LengthFieldPrepender());
                            socketChannel.pipeline().addLast(new ProtobufEncoder());
                            socketChannel.pipeline().addLast(new SubReqClientHandler());
                        }
                    });
            ChannelFuture f = b.connect(host, port).sync();
            f.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            group.shutdownGracefully();
        }
    }
}

6. SubReqClientHandler.java

import cn.ddlover.nettystudy.protobuf.SubscribeReqProto;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
 
import java.util.ArrayList;
import java.util.List;
 
public class SubReqClientHandler extends ChannelInboundHandlerAdapter {
 
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        for (int i =0;i<10;i++) {
            ctx.write(subReq(i));
        }
        ctx.flush();
    }
 
    private SubscribeReqProto.SubscribeReq subReq(int i) {
        SubscribeReqProto.SubscribeReq.Builder builder = SubscribeReqProto.SubscribeReq.newBuilder();
        builder.setSubReqID(i);
        builder.setUserName("張三");
        builder.setProductName("Netty Book");
        List<String> address = new ArrayList<>();
        address.add("NanJing YuHuaTai");
        address.add("BeiJing LiuLiChang");
        address.add("ShenZhen HongShuLin");
        builder.addAllAddress(address);
        return builder.build();
    }
 
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        System.out.println("Receive server response : ["+ msg +"]");
    }
 
 
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }
}

代碼部分到此就結(jié)束了，然后分別運(yùn)行SubReqServer和SubReqClient， 就可以發(fā)現(xiàn)運(yùn)行成功了。

這里要注意的事，調(diào)用toString的時(shí)候，中文在控制臺(tái)打印的是字節(jié)，而調(diào)用對(duì)應(yīng)屬性的getter方法的時(shí)候，是可以做中文的判斷的，顯然這里protobuf的toString沒(méi)有被修改好呀。

當(dāng)然，我們也可以發(fā)現(xiàn)，netty本身已經(jīng)封裝好了對(duì)谷歌的protobuf的支持。Netty還是很強(qiáng)大的。

到此這篇關(guān)于Netty結(jié)合Protobuf進(jìn)行編解碼的文章就介紹到這了,更多相關(guān)Netty結(jié)合Protobuf編解碼內(nèi)容請(qǐng)搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持腳本之家！

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