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java | 定长解码器

发表于 分类于 ， ， ， ， Valine：

下面假设服务器和客户端约定好，10 字节为一个完整数据长度。

客户端

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package com.redisc;

import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;

public class Client {
    static final Logger log = LoggerFactory.getLogger(Client.class);

    public static void main(String[] args) throws IOException, InterruptedException {
        send();
    }

    public static void send() {
        NioEventLoopGroup worker = new NioEventLoopGroup();

        try {
            Bootstrap bootstrap = new Bootstrap();
            bootstrap.channel(NioSocketChannel.class);
            bootstrap.group(worker);
            bootstrap.handler(new ChannelInitializer<SocketChannel>() {
                @Override
                protected void initChannel(SocketChannel socketChannel) throws Exception {
                    socketChannel.pipeline().addLast(new LoggingHandler(LogLevel.DEBUG));
                    socketChannel.pipeline().addLast(new ChannelInboundHandlerAdapter() {
                        @Override
                        // 会在连接 channel 建立成功后，触发 active 事件
                        public void channelActive(ChannelHandlerContext ctx) throws Exception {
                            ByteBuf buf = ctx.alloc().buffer();
                            char c = '0';
                            StringBuilder s = new StringBuilder();
                            for (int j = 0; j < 3; j++) {
                                for (int i = 0; i < 10; i++) {
                                    s.append(c);
                                    c++;
                                }
                                buf.writeBytes(s.toString().getBytes());
                            }
                            ctx.writeAndFlush(buf);
                        }
                    });
                }
            });
            ChannelFuture channelFuture = bootstrap.connect("127.0.0.1", 8000);
            channelFuture.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            log.error("error", e);
        } finally {
            worker.shutdownGracefully();
        }
    }
}

输出

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16:13:20.288 [nioEventLoopGroup-2-1] DEBUG io.netty.handler.logging.LoggingHandler - [id: 0x92662e5f, L:/127.0.0.1:51105 - R:/127.0.0.1:8000] WRITE: 60B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 |0123456789012345|
|00000010| 36 37 38 39 3a 3b 3c 3d 3e 3f 40 41 42 43 30 31 |6789:;<=>?@ABC01|
|00000020| 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 40 41 |23456789:;<=>?@A|
|00000030| 42 43 44 45 46 47 48 49 4a 4b 4c 4d             |BCDEFGHIJKLM    |
+--------+-------------------------------------------------+----------------+
16:13:20.289 [nioEventLoopGroup-2-1] DEBUG io.netty.handler.logging.LoggingHandler - [id: 0x92662e5f, L:/127.0.0.1:51105 - R:/127.0.0.1:8000] FLUSH

客户端这边依然存在粘包现象。

服务端

增加一个 channelhandler，即 socketChannel.pipeline().addLast(new FixedLengthFrameDecoder(10));

遇到十个字节才开始解，不够就等着。

代码为

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package com.redisc;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.AdaptiveRecvByteBufAllocator;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.FixedLengthFrameDecoder;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import lombok.extern.slf4j.Slf4j;

import java.io.IOException;


@Slf4j
public class Server {

    public static void main(String[] args) throws IOException {
        NioEventLoopGroup boss = new NioEventLoopGroup();
        NioEventLoopGroup worker = new NioEventLoopGroup();

        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap.channel(NioServerSocketChannel.class);
            serverBootstrap.group(boss, worker);
            serverBootstrap.childHandler(new ChannelInitializer<SocketChannel>() {
                @Override
                protected void initChannel(SocketChannel socketChannel) throws Exception {
                    socketChannel.pipeline().addLast(new FixedLengthFrameDecoder(10));
                    socketChannel.pipeline().addLast(new LoggingHandler(LogLevel.DEBUG));
                }
            });
            ChannelFuture channelFuture = serverBootstrap.bind(8000).sync();
            channelFuture.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            log.error("error", e);
        } finally {
            boss.shutdownGracefully();
            worker.shutdownGracefully();
        }

    }
}

输出

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16:13:20.345 [nioEventLoopGroup-3-1] DEBUG io.netty.util.ResourceLeakDetectorFactory - Loaded default ResourceLeakDetector: io.netty.util.ResourceLeakDetector@23dd2117
16:13:20.371 [nioEventLoopGroup-3-1] DEBUG io.netty.handler.logging.LoggingHandler - [id: 0x715fb28d, L:/127.0.0.1:8000 - R:/127.0.0.1:51105] READ: 10B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 30 31 32 33 34 35 36 37 38 39                   |0123456789      |
+--------+-------------------------------------------------+----------------+
16:13:20.371 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded inbound message PooledSlicedByteBuf(ridx: 0, widx: 10, cap: 10/10, unwrapped: PooledUnsafeDirectByteBuf(ridx: 10, widx: 60, cap: 2048)) that reached at the tail of the pipeline. Please check your pipeline configuration.
16:13:20.371 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded message pipeline : [FixedLengthFrameDecoder#0, LoggingHandler#0, DefaultChannelPipeline$TailContext#0]. Channel : [id: 0x715fb28d, L:/127.0.0.1:8000 - R:/127.0.0.1:51105].
16:13:20.371 [nioEventLoopGroup-3-1] DEBUG io.netty.handler.logging.LoggingHandler - [id: 0x715fb28d, L:/127.0.0.1:8000 - R:/127.0.0.1:51105] READ: 10B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 30 31 32 33 34 35 36 37 38 39                   |0123456789      |
+--------+-------------------------------------------------+----------------+
16:13:20.371 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded inbound message PooledSlicedByteBuf(ridx: 0, widx: 10, cap: 10/10, unwrapped: PooledUnsafeDirectByteBuf(ridx: 20, widx: 60, cap: 2048)) that reached at the tail of the pipeline. Please check your pipeline configuration.
16:13:20.371 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded message pipeline : [FixedLengthFrameDecoder#0, LoggingHandler#0, DefaultChannelPipeline$TailContext#0]. Channel : [id: 0x715fb28d, L:/127.0.0.1:8000 - R:/127.0.0.1:51105].
16:13:20.372 [nioEventLoopGroup-3-1] DEBUG io.netty.handler.logging.LoggingHandler - [id: 0x715fb28d, L:/127.0.0.1:8000 - R:/127.0.0.1:51105] READ: 10B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 3a 3b 3c 3d 3e 3f 40 41 42 43                   |:;<=>?@ABC      |
+--------+-------------------------------------------------+----------------+
16:13:20.372 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded inbound message PooledSlicedByteBuf(ridx: 0, widx: 10, cap: 10/10, unwrapped: PooledUnsafeDirectByteBuf(ridx: 30, widx: 60, cap: 2048)) that reached at the tail of the pipeline. Please check your pipeline configuration.
16:13:20.372 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded message pipeline : [FixedLengthFrameDecoder#0, LoggingHandler#0, DefaultChannelPipeline$TailContext#0]. Channel : [id: 0x715fb28d, L:/127.0.0.1:8000 - R:/127.0.0.1:51105].
16:13:20.372 [nioEventLoopGroup-3-1] DEBUG io.netty.handler.logging.LoggingHandler - [id: 0x715fb28d, L:/127.0.0.1:8000 - R:/127.0.0.1:51105] READ: 10B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 30 31 32 33 34 35 36 37 38 39                   |0123456789      |
+--------+-------------------------------------------------+----------------+
16:13:20.373 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded inbound message PooledSlicedByteBuf(ridx: 0, widx: 10, cap: 10/10, unwrapped: PooledUnsafeDirectByteBuf(ridx: 40, widx: 60, cap: 2048)) that reached at the tail of the pipeline. Please check your pipeline configuration.
16:13:20.373 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded message pipeline : [FixedLengthFrameDecoder#0, LoggingHandler#0, DefaultChannelPipeline$TailContext#0]. Channel : [id: 0x715fb28d, L:/127.0.0.1:8000 - R:/127.0.0.1:51105].
16:13:20.373 [nioEventLoopGroup-3-1] DEBUG io.netty.handler.logging.LoggingHandler - [id: 0x715fb28d, L:/127.0.0.1:8000 - R:/127.0.0.1:51105] READ: 10B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 3a 3b 3c 3d 3e 3f 40 41 42 43                   |:;<=>?@ABC      |
+--------+-------------------------------------------------+----------------+
16:13:20.373 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded inbound message PooledSlicedByteBuf(ridx: 0, widx: 10, cap: 10/10, unwrapped: PooledUnsafeDirectByteBuf(ridx: 50, widx: 60, cap: 2048)) that reached at the tail of the pipeline. Please check your pipeline configuration.
16:13:20.373 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded message pipeline : [FixedLengthFrameDecoder#0, LoggingHandler#0, DefaultChannelPipeline$TailContext#0]. Channel : [id: 0x715fb28d, L:/127.0.0.1:8000 - R:/127.0.0.1:51105].
16:13:20.373 [nioEventLoopGroup-3-1] DEBUG io.netty.handler.logging.LoggingHandler - [id: 0x715fb28d, L:/127.0.0.1:8000 - R:/127.0.0.1:51105] READ: 10B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 44 45 46 47 48 49 4a 4b 4c 4d                   |DEFGHIJKLM      |
+--------+-------------------------------------------------+----------------+
16:13:20.374 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded inbound message PooledSlicedByteBuf(ridx: 0, widx: 10, cap: 10/10, unwrapped: PooledUnsafeDirectByteBuf(ridx: 60, widx: 60, cap: 2048)) that reached at the tail of the pipeline. Please check your pipeline configuration.
16:13:20.375 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded message pipeline : [FixedLengthFrameDecoder#0, LoggingHandler#0, DefaultChannelPipeline$TailContext#0]. Channel : [id: 0x715fb28d, L:/127.0.0.1:8000 - R:/127.0.0.1:51105].
16:13:20.376 [nioEventLoopGroup-3-1] DEBUG io.netty.handler.logging.LoggingHandler - [id: 0x715fb28d, L:/127.0.0.1:8000 - R:/127.0.0.1:51105] READ COMPLETE
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