Netty结合Protobuf进行编解码的示例分析
这篇文章主要介绍了Netty结合Protobuf进行编解码的示例分析，具有一定借鉴价值，感兴趣的朋友可以参考下，希望大家阅读完这篇文章之后大有收获，下面让小编带着大家一起了解一下。
1. 什么是Protobuf？
Protobuf全称是Google Protocol Buffers, 它是谷歌公司开源的一个序列化框架。
它将数据结构以.proto文件进行描述，通过代码生成工具可以生成对应数据结构的POJO对象和Protobuf相关的方法和属性。
它的特点如下：
结构化数据存储格式
高效的编解码性能
语言无关、平台无关、扩展性好
官方支持多个语言（java，c++，python，c#等）
2. 下载安装
Protobuf已经托管在github上，可以在release页面下载，本案例使用的是v3.6（要下载后缀为-win32.zip的）。
下载后，将压缩包进行解压。这里主要用到bin目录下的protoc.exe。
3. 定义好proto文件
SubscribeReq.proto
// 区分不同的protobuf版本，必须有
syntax = "proto2";
package netty;
// 生成的目标类的包路径
option java_package = "cn.ddlover.nettystudy.protobuf";
// 生成的目标类的名字
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;
}
此时项目结构如下
重点关注一下两个proto文件的位置，是位于项目的根路径下
4. 分别执行以下命令
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
这里需要把protoc.exe的位置换成自己的， --java_out命令设置的是proto文件中java_package指令的父目录。
5. 此时项目结构如下
下面开始代码方面的开发，
1. 先贴一波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. 这里贴上完整代码的项目结构
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版本图书订购代码
*/
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 {
// 半包处理
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 ("张三".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书籍下单成功，3天后将会送到你的住处");
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 {
// 半包处理
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("张三");
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();
}
}
代码部分到此就结束了，然后分别运行SubReqServer和SubReqClient， 就可以发现运行成功了。
这里要注意的事，调用toString的时候，中文在控制台打印的是字节，而调用对应属性的getter方法的时候，是可以做中文的判断的，显然这里protobuf的toString没有被修改好呀。
当然，我们也可以发现，netty本身已经封装好了对谷歌的protobuf的支持。Netty还是很强大的。
感谢你能够认真阅读完这篇文章，希望小编分享的“Netty结合Protobuf进行编解码的示例分析”这篇文章对大家有帮助，同时也希望大家多多支持亿速云，关注行业资讯频道，更多相关知识等着你来学习!