netty借助protobuf发送数据

---

前言

---

netty借助protobuf传输数据。

一、protobuf是什么？

protobuf是google开源的请求和响应格式，有自己独特的编解码方式；protobuf相较于xml格式来说体积更小、速度更快；并且支持跨语言。

二、使用步骤

1.引入库

代码如下（示例）：

mysql的驱动会带一个protobuf的版本,需要注意

		 <dependency> 
		 	<groupId>mysqlgroupId> 
		 	<artifactId>mysql-connector-javaartifactId> 
			<version>8.0.19version>
			 <exclusions>
				 <exclusion>
					 <groupId>com.google.protobufgroupId>
					 <artifactId>protobuf-javaartifactId>
				 exclusion>
			 exclusions>
		 dependency>

		<dependency>
			<groupId>io.nettygroupId>
			<artifactId>netty-allartifactId>
			<version>4.1.80.Finalversion>
		dependency>

		<dependency>
			<groupId>com.google.api.grpcgroupId>
			<artifactId>proto-google-common-protosartifactId>
			<version>2.9.2version>
		dependency>

2.编写proto文件

idea可以安装Protobuf插件,有提示和校验

student.proto：

syntax="proto3";
//option java_package="netty.proto";
option java_outer_classname="StudentPOJO";
message Student{
     int32 id=1;
     string name=2;
}

3.编译proto文件

下载解压到本地，找到bin目录下的protoc.exe复制到工程下
protoc-21.7-win64.zip

4.编写netty测试程序

NettyServer.java

package netty.proto;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.protobuf.ProtobufDecoder;

/**
 * Create by zjg on 2022/9/12
 */
public class NettyServer {
    public static void main(String[] args) {
        NioEventLoopGroup bossGroup = null;
        NioEventLoopGroup workGroup= null;
        try {
            bossGroup=new NioEventLoopGroup();
            workGroup=new NioEventLoopGroup();
            ServerBootstrap bootstrap=new ServerBootstrap();
            bootstrap.group(bossGroup,workGroup)
                    .channel(NioServerSocketChannel.class)
                    .option(ChannelOption.SO_BACKLOG,128)
                    .childOption(ChannelOption.SO_KEEPALIVE,true)
                    .childHandler(new ChannelInitializer() {
                        @Override
                        protected void initChannel(Channel channel) throws Exception {
                            ChannelPipeline pipeline = channel.pipeline();
                            pipeline.addLast(new ProtobufDecoder(StudentPOJO.Student.getDefaultInstance()));
                            pipeline.addLast(new NettyServerHandler());
                        }
                    });
            ChannelFuture channelFuture = bootstrap.bind(8080).sync();
            System.out.println("服务端启动完成!");
            channelFuture.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            bossGroup.shutdownGracefully();
            workGroup.shutdownGracefully();
        }
    }
}

NettyServerHandler.java

package netty.proto;

import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

/**
 * Create by zjg on 2022/9/12
 */
public class NettyServerHandler extends ChannelInboundHandlerAdapter {
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        StudentPOJO.Student student= (StudentPOJO.Student) msg;
        System.out.println("接收到客户端请求:");
        System.out.println("id:"+student.getId()+";name:"+student.getName());
        String res= "服务器响应["+ LocalDateTime.now().format(DateTimeFormatter.ISO_DATE)+" "+LocalDateTime.now().format(DateTimeFormatter.ISO_TIME)+"]:--YYDS";
        System.out.println("服务端响应:"+res);
        ctx.writeAndFlush(Unpooled.copiedBuffer(res,CharsetUtil.UTF_8));
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        System.out.println("异常");
        cause.printStackTrace();
        ctx.close();
    }
}

NettyClient.java

package netty.proto;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
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;

/**
 * Create by zjg on 2022/9/12
 */
public class NettyClient {
    //protoc.exe --java_out=. student.proto
    public static void main(String[] args) {
        NioEventLoopGroup nioEventLoopGroup=null;
        try {
            nioEventLoopGroup=new NioEventLoopGroup();
            Bootstrap bootstrap=new Bootstrap();
            bootstrap.group(nioEventLoopGroup)
                    .channel(NioSocketChannel.class)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel socketChannel) throws Exception {
                            ChannelPipeline pipeline = socketChannel.pipeline();
                            pipeline.addLast(new ProtobufEncoder());
                            pipeline.addLast(new NettyClientHandler());
                        }
                    });
            ChannelFuture channelFuture = bootstrap.connect("127.0.0.1", 8080).sync();
            channelFuture.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            nioEventLoopGroup.shutdownGracefully();
        }

    }
}

NettyClientHandler.java

package netty.proto;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;

/**
 * Create by zjg on 2022/9/12
 */
public class NettyClientHandler extends ChannelInboundHandlerAdapter {
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        StudentPOJO.Student student = StudentPOJO.Student.newBuilder().setId(1).setName("哈哈哈").build();
        ctx.writeAndFlush(student);
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf byteBuf= (ByteBuf) msg;
        System.out.println("接收到服务端响应:"+byteBuf.toString(CharsetUtil.UTF_8));
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }
}

StudentPOJO.java

package netty.proto;// Generated by the protocol buffer compiler.  DO NOT EDIT!
// source: Student.proto

public final class StudentPOJO {
  private StudentPOJO() {}
  public static void registerAllExtensions(
      com.google.protobuf.ExtensionRegistryLite registry) {
  }

  public static void registerAllExtensions(
      com.google.protobuf.ExtensionRegistry registry) {
    registerAllExtensions(
        (com.google.protobuf.ExtensionRegistryLite) registry);
  }
  public interface StudentOrBuilder extends
      // @@protoc_insertion_point(interface_extends:Student)
      com.google.protobuf.MessageOrBuilder {

    /**
     * int32 id = 1;
     * @return The id.
     */
    int getId();

    /**
     * string name = 2;
     * @return The name.
     */
    java.lang.String getName();
    /**
     * string name = 2;
     * @return The bytes for name.
     */
    com.google.protobuf.ByteString
        getNameBytes();
  }
  /**
   * Protobuf type {@code Student}
   */
  public static final class Student extends
      com.google.protobuf.GeneratedMessageV3 implements
      // @@protoc_insertion_point(message_implements:Student)
      StudentOrBuilder {
  private static final long serialVersionUID = 0L;
    // Use Student.newBuilder() to construct.
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      super(builder);
    }
    private Student() {
      name_ = "";
    }

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    @SuppressWarnings({"unused"})
    protected java.lang.Object newInstance(
        UnusedPrivateParameter unused) {
      return new Student();
    }

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    public final com.google.protobuf.UnknownFieldSet
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    public int getId() {
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    }
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    @java.lang.Override
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      if (getId()
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    @java.lang.Override
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    public static StudentPOJO.Student parseFrom(
        java.nio.ByteBuffer data)
        throws com.google.protobuf.InvalidProtocolBufferException {
      return PARSER.parseFrom(data);
    }
    public static StudentPOJO.Student parseFrom(
        java.nio.ByteBuffer data,
        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
        throws com.google.protobuf.InvalidProtocolBufferException {
      return PARSER.parseFrom(data, extensionRegistry);
    }
    public static StudentPOJO.Student parseFrom(
        com.google.protobuf.ByteString data)
        throws com.google.protobuf.InvalidProtocolBufferException {
      return PARSER.parseFrom(data);
    }
    public static StudentPOJO.Student parseFrom(
        com.google.protobuf.ByteString data,
        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
        throws com.google.protobuf.InvalidProtocolBufferException {
      return PARSER.parseFrom(data, extensionRegistry);
    }
    public static StudentPOJO.Student parseFrom(byte[] data)
        throws com.google.protobuf.InvalidProtocolBufferException {
      return PARSER.parseFrom(data);
    }
    public static StudentPOJO.Student parseFrom(
        byte[] data,
        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
        throws com.google.protobuf.InvalidProtocolBufferException {
      return PARSER.parseFrom(data, extensionRegistry);
    }
    public static StudentPOJO.Student parseFrom(java.io.InputStream input)
        throws java.io.IOException {
      return com.google.protobuf.GeneratedMessageV3
          .parseWithIOException(PARSER, input);
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    public static StudentPOJO.Student parseFrom(
        java.io.InputStream input,
        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
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          .parseWithIOException(PARSER, input, extensionRegistry);
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        throws java.io.IOException {
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          .parseDelimitedWithIOException(PARSER, input);
    }
    public static StudentPOJO.Student parseDelimitedFrom(
        java.io.InputStream input,
        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
        throws java.io.IOException {
      return com.google.protobuf.GeneratedMessageV3
          .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
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    public static StudentPOJO.Student parseFrom(
        com.google.protobuf.CodedInputStream input)
        throws java.io.IOException {
      return com.google.protobuf.GeneratedMessageV3
          .parseWithIOException(PARSER, input);
    }
    public static StudentPOJO.Student parseFrom(
        com.google.protobuf.CodedInputStream input,
        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
        throws java.io.IOException {
      return com.google.protobuf.GeneratedMessageV3
          .parseWithIOException(PARSER, input, extensionRegistry);
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    @java.lang.Override
    public Builder newBuilderForType() { return newBuilder(); }
    public static Builder newBuilder() {
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    public static Builder newBuilder(StudentPOJO.Student prototype) {
      return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
    }
    @java.lang.Override
    public Builder toBuilder() {
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          ? new Builder() : new Builder().mergeFrom(this);
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    @java.lang.Override
    protected Builder newBuilderForType(
        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
      Builder builder = new Builder(parent);
      return builder;
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    /**
     * Protobuf type {@code Student}
     */
    public static final class Builder extends
        com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
        // @@protoc_insertion_point(builder_implements:Student)
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      // @@protoc_insertion_point(builder_scope:Student)
    }

    // @@protoc_insertion_point(class_scope:Student)
    private static final StudentPOJO.Student DEFAULT_INSTANCE;
    static {
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    }

    public static StudentPOJO.Student getDefaultInstance() {
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    }

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    @java.lang.Override
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  }
  private static  com.google.protobuf.Descriptors.FileDescriptor
      descriptor;
  static {
    java.lang.String[] descriptorData = {
      "\n\rStudent.proto\"#\n\007Student\022\n\n\002id\030\001 \001(\005\022\014" +
      "\n\004name\030\002 \001(\tB\rB\013StudentPOJOb\006proto3"
    };
    descriptor = com.google.protobuf.Descriptors.FileDescriptor
      .internalBuildGeneratedFileFrom(descriptorData,
        new com.google.protobuf.Descriptors.FileDescriptor[] {
        });
    internal_static_Student_descriptor =
      getDescriptor().getMessageTypes().get(0);
    internal_static_Student_fieldAccessorTable = new
      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
        internal_static_Student_descriptor,
        new java.lang.String[] { "Id", "Name", });
  }

  // @@protoc_insertion_point(outer_class_scope)
}

总结

。