Netty結(jié)合Protobuf進(jìn)行編解碼的方法
一般在使用netty時,數(shù)據(jù)傳輸?shù)臅r候都會選擇對傳輸?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(無法跨語言,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:
- Google的Protobuf
- Facebook的Thrift
- JBoss的Marshalling
今天我們簡單介紹一下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全稱是Google Protocol Buffers, 它是谷歌公司開源的一個序列化框架。
它將數(shù)據(jù)結(jié)構(gòu)以.proto文件進(jìn)行描述,通過代碼生成工具可以生成對應(yīng)數(shù)據(jù)結(jié)構(gòu)的POJO對象和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)存儲格式
- 高效的編解碼性能
- 語言無關(guān)、平臺無關(guān)、擴(kuò)展性好
- 官方支持多個語言(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)類的包路徑
option java_package = "cn.ddlover.nettystudy.protobuf";
// 生成的目標(biāo)類的名字
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;
}
此時項(xiàng)目結(jié)構(gòu)如下

重點(diǎn)關(guān)注一下兩個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. 此時項(xiàng)目結(jié)構(gòu)如下

下面開始代碼方面的開發(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版本圖書訂購代碼
*/
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書籍下單成功,3天后將會送到你的住處");
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的時候,中文在控制臺打印的是字節(jié),而調(diào)用對應(yīng)屬性的getter方法的時候,是可以做中文的判斷的,顯然這里protobuf的toString沒有被修改好呀。
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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