這篇文章主要介紹了Netty結合Protobuf進行編解碼的示例分析，具有一定借鑒價值，感興趣的朋友可以參考下，希望大家閱讀完這篇文章之后大有收獲，下面讓小編帶著大家一起了解一下。
Protobuf全稱是Google Protocol Buffers, 它是谷歌公司開源的一個序列化框架。
它將數據結構以.proto文件進行描述，通過代碼生成工具可以生成對應數據結構的POJO對象和Protobuf相關的方法和屬性。
它的特點如下：
結構化數據存儲格式
高效的編解碼性能
語言無關、平臺無關、擴展性好
官方支持多個語言（java，c++，python，c#等）
Protobuf已經托管在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，將壓縮包進行解壓。這里主要用到bin目錄下的protoc.exe。
SubscribeReq.proto
// 區分不同的protobuf版本，必須有
syntax = "proto2";
package netty;
// 生成的目標類的包路徑
option java_package = "cn.ddlover.nettystudy.protobuf";
// 生成的目標類的名字
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;
}此時項目結構如下
重點關注一下兩個proto文件的位置，是位于項目的根路徑下
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命令設置的是proto文件中java_package指令的父目錄。
下面開始代碼方面的開發，
<?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>
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();
}
}
}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();
}
}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();
}
}
}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();
}
}代碼部分到此就結束了，然后分別運行SubReqServer和SubReqClient， 就可以發現運行成功了。
這里要注意的事，調用toString的時候，中文在控制臺打印的是字節，而調用對應屬性的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。
當然，我們也可以發現，netty本身已經封裝好了對谷歌的protobuf的支持。Netty還是很強大的。
感謝你能夠認真閱讀完這篇文章，希望小編分享的“Netty結合Protobuf進行編解碼的示例分析”這篇文章對大家有幫助，同時也希望大家多多支持億速云，關注億速云行業資訊頻道，更多相關知識等著你來學習!
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