Netty学习——Netty和Protobuf的整合（一）

Netty学习——Netty和Protobuf的整合

---

Protobuf作为序列化的工具，将序列化后的数据，通过Netty来进行在网络上的传输

1.将proto文件里的java包的位置修改一下，然后再执行一下protoc

 异常捕获：启动服务器端正常，在启动客户端的时候，发送消息，报错

警告: An exceptionCaught() event was fired, and it reached at the tail of the pipeline. It usually means the last handler in the pipeline did not handle the exception.
io.netty.handler.codec.DecoderException: com.google.protobuf.InvalidProtocolBufferException: Protocol message contained an invalid tag (zero).
    at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:98)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
    at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:326)
    at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:313)
    at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:427)
    at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:281)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
    at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1422)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
    at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:931)
    at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163)
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:700)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:635)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:552)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:514)
    at io.netty.util.concurrent.SingleThreadEventExecutor$6.run(SingleThreadEventExecutor.java:1050)
    at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
    at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
    at java.lang.Thread.run(Thread.java:748)
Caused by: com.google.protobuf.InvalidProtocolBufferException: Protocol message contained an invalid tag (zero).
    at com.google.protobuf.InvalidProtocolBufferException.invalidTag(InvalidProtocolBufferException.java:102)
    at com.google.protobuf.CodedInputStream$ArrayDecoder.readTag(CodedInputStream.java:627)
    at com.dawa.netty.sixthexample.MyDataInfo$Person.<init>(MyDataInfo.java:109)
    at com.dawa.netty.sixthexample.MyDataInfo$Person.<init>(MyDataInfo.java:69)
    at com.dawa.netty.sixthexample.MyDataInfo$Person$1.parsePartialFrom(MyDataInfo.java:881)
    at com.dawa.netty.sixthexample.MyDataInfo$Person$1.parsePartialFrom(MyDataInfo.java:875)
    at com.google.protobuf.AbstractParser.parsePartialFrom(AbstractParser.java:158)
    at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:191)
    at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:197)
    at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:48)
    at io.netty.handler.codec.protobuf.ProtobufDecoder.decode(ProtobufDecoder.java:121)
    at io.netty.handler.codec.protobuf.ProtobufDecoder.decode(ProtobufDecoder.java:65)
    at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:88)
    ... 23 more

十二月 03, 2019 11:01:51 上午 io.netty.channel.DefaultChannelPipeline onUnhandledInboundException
警告: An exceptionCaught() event was fired, and it reached at the tail of the pipeline. It usually means the last handler in the pipeline did not handle the exception.
io.netty.handler.codec.DecoderException: com.google.protobuf.InvalidProtocolBufferException: While parsing a protocol message, the input ended unexpectedly in the middle of a field.  This could mean either that the input has been truncated or that an embedded message misreported its own length.
    at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:98)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
    at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:326)
    at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:300)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
    at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1422)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
    at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:931)
    at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163)
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:700)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:635)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:552)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:514)
    at io.netty.util.concurrent.SingleThreadEventExecutor$6.run(SingleThreadEventExecutor.java:1050)
    at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
    at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
    at java.lang.Thread.run(Thread.java:748)
Caused by: com.google.protobuf.InvalidProtocolBufferException: While parsing a protocol message, the input ended unexpectedly in the middle of a field.  This could mean either that the input has been truncated or that an embedded message misreported its own length.
    at com.google.protobuf.InvalidProtocolBufferException.truncatedMessage(InvalidProtocolBufferException.java:84)
    at com.google.protobuf.CodedInputStream$ArrayDecoder.readRawByte(CodedInputStream.java:1238)
    at com.google.protobuf.CodedInputStream$ArrayDecoder.readRawVarint64SlowPath(CodedInputStream.java:1126)
    at com.google.protobuf.CodedInputStream$ArrayDecoder.readRawVarint32(CodedInputStream.java:1020)
    at com.google.protobuf.CodedInputStream$ArrayDecoder.readTag(CodedInputStream.java:623)
    at com.dawa.netty.sixthexample.MyDataInfo$Person.<init>(MyDataInfo.java:109)
    at com.dawa.netty.sixthexample.MyDataInfo$Person.<init>(MyDataInfo.java:69)
    at com.dawa.netty.sixthexample.MyDataInfo$Person$1.parsePartialFrom(MyDataInfo.java:881)
    at com.dawa.netty.sixthexample.MyDataInfo$Person$1.parsePartialFrom(MyDataInfo.java:875)
    at com.google.protobuf.AbstractParser.parsePartialFrom(AbstractParser.java:158)
    at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:191)
    at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:197)
    at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:48)
    at io.netty.handler.codec.protobuf.ProtobufDecoder.decode(ProtobufDecoder.java:121)
    at io.netty.handler.codec.protobuf.ProtobufDecoder.decode(ProtobufDecoder.java:65)
    at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:88)
    ... 21 more

开始找问题：
1.io.netty.handler.codec.DecoderException: 在解码过程中出错，可能是服务器端出的错
2.Caused by: com.google.protobuf.InvalidProtocolBufferException: Protocol message contained an invalid tag (zero).
3.While parsing a protocol message, the input ended unexpectedly in the middle of a field. This could mean either that the input has been truncated or that an embedded message misreported its own length.

检查了一下代码：猜测了一下：成了，效果图如下

 可怕，原因竟然出现在编码器添加的顺序不同导致的： 正确的顺序是这样的：

@Override
protected void initChannel(SocketChannel ch) throws Exception {
    ChannelPipeline pipeline = ch.pipeline();
    //这里和之前的不一样了，但也就是处理器的不一样
    //编解码处理器,protobuf提供的专门的编解码器.4个处理器
    pipeline.addLast(new ProtobufVarint32FrameDecoder());
    //Decoder是重点，解码器，将字节码转换成想要的数据类型
    //参数  messageLite，外层的要转换的类的实例
    pipeline.addLast(new ProtobufDecoder(MyDataInfo.Person.getDefaultInstance()));
    pipeline.addLast(new ProtobufVarint32LengthFieldPrepender());
    pipeline.addLast(new ProtobufEncoder());
    pipeline.addLast(new TestServerHandler());
}

接下来存放一下完整的客户端和服务器端的代码
proto文件

yntax ="proto2";

package com.dawa.protobuf;

option optimize_for = SPEED;
option java_package ="com.dawa.netty.sixthexample";
option java_outer_classname = "MyDataInfo";

message Person{
    required string name = 1;
    optional int32 age = 2;
    optional string address = 3;
}

message Person2{
    required string name = 1;
    optional int32 age = 2;
    optional string address = 3;
}

服务器端代码：

package com.dawa.netty.sixthexample;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;

/**
 * @Title: TestServer
 * @Author: 大娃
 * @Date: 2019/12/3 10:01
 * @Description:
 */
public class TestServer {
    public static void main(String[] args) throws Exception {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class)
            .handler(new LoggingHandler(LogLevel.INFO))
                    .childHandler(new TestServerInitializer());

            ChannelFuture channelFuture = serverBootstrap.bind(8899).sync();
            channelFuture.channel().closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

package com.dawa.netty.sixthexample;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;

/**
 * @Title: TestServerHandler
 * @Author: 大娃
 * @Date: 2019/12/3 10:09
 * @Description: handler本身是个泛型，这里的泛型就是取 要处理的类型
 */
public class TestServerHandler extends SimpleChannelInboundHandler<MyDataInfo.Person> {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, MyDataInfo.Person msg) throws Exception {
        //对接受到的消息进行处理:
        System.out.println(msg.getName());
        System.out.println(msg.getAge());
        System.out.println(msg.getAddress());
    }
}

package com.dawa.netty.sixthexample;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
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;

/**
 * @Title: TestServerInitializer
 * @Author: 大娃
 * @Date: 2019/12/3 10:05
 * @Description:
 */
public class TestServerInitializer extends ChannelInitializer<SocketChannel> {

    @Override
    protected void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();
        //这里和之前的不一样了，但也就是处理器的不一样
        //编解码处理器,protobuf提供的专门的编解码器.4个处理器
        pipeline.addLast(new ProtobufVarint32FrameDecoder());
        //Decoder是重点，解码器，将字节码转换成想要的数据类型
        //参数  messageLite，外层的要转换的类的实例
        pipeline.addLast(new ProtobufDecoder(MyDataInfo.Person.getDefaultInstance()));
        pipeline.addLast(new ProtobufVarint32LengthFieldPrepender());
        pipeline.addLast(new ProtobufEncoder());
        pipeline.addLast(new TestServerHandler());
    }
}

客户端代码

package com.dawa.netty.sixthexample;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;

/**
 * @Title: TestClient
 * @Author: 大娃
 * @Date: 2019/12/3 10:15
 * @Description: 客户端内容
 */
public class TestClient {
    public static void main(String[] args) throws Exception {
        EventLoopGroup eventLoopGroup = new NioEventLoopGroup();

        try {
            Bootstrap bootstrap = new Bootstrap();
            bootstrap.group(eventLoopGroup).channel(NioSocketChannel.class)
            .handler(new TestClientInitializer());
            //注意此处，使用的是connect,不是使用的bind
            ChannelFuture channelFuture = bootstrap.connect("localhost", 8899).sync();
            channelFuture.channel().closeFuture().sync();
        } finally {
            eventLoopGroup.shutdownGracefully();
        }
    }
}

package com.dawa.netty.sixthexample;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
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;

/**
 * @Title: TestClientInitializer
 * @Author: 大娃
 * @Date: 2019/12/3 10:43
 * @Description:
 */
public class TestClientInitializer extends ChannelInitializer<SocketChannel> {
    @Override
    protected void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();
        //这里和之前的不一样了，但也就是处理器的不一样
        //编解码处理器,protobuf提供的专门的编解码器.4个处理器
        pipeline.addLast(new ProtobufVarint32FrameDecoder());
        //Decoder是重点，解码器，将字节码转换成想要的数据类型
        //参数  messageLite，外层的要转换的类的实例
        pipeline.addLast(new ProtobufDecoder(MyDataInfo.Person.getDefaultInstance()));
        pipeline.addLast(new ProtobufVarint32LengthFieldPrepender());
        pipeline.addLast(new ProtobufEncoder());
        //自己的处理器
        pipeline.addLast(new TestClientHandler());
    }
}

package com.dawa.netty.sixthexample;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;

/**
 * @Title: TestClientHandler
 * @Author: 大娃
 * @Date: 2019/12/3 10:44
 * @Description:
 */
public class TestClientHandler extends SimpleChannelInboundHandler<MyDataInfo.Person> {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, MyDataInfo.Person msg) throws Exception {

    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        //处于活动状态
        MyDataInfo.Person person = MyDataInfo.Person.newBuilder().setName("大娃").setAge(22).setAddress("北京").build();
        ctx.channel().writeAndFlush(person);
    }
}

这程序是有瑕疵的，解码器那里不通用，耦合性太强，有两个很明显的问题，但是要怎么解决呢？

会专门写个帖子进行分析，Netty学习——Netty和Protobuf的整合（二）