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java | 行解码器

发表于 分类于 ， ， ， ， Valine：

就是数据最后有一个分隔符，来分割各个数据。

netty 有两种行解码器

  • new LineBasedFrameDecoder(1024)
    • 使用 '\n' 作为分隔符
  • new DelimiterBasedFrameDecoder(1024, Unpooled.copiedBuffer("$_".getBytes()))
    • 自定义分隔符

里面的 1024 是设置的最大长度，如果超过这个长度还没有找到分隔符，则会放弃这段数据。

客户端

自定义 3 个随机长度的 '\n' 结尾的数据。

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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;
import java.util.Random;

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++) {
                                int k = new Random().nextInt(100);
                                for (int i = 0; i < k; i++) {
                                    s.append(c);
                                }
                                s.append("\n");
                            }
                            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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16:41:27.623 [nioEventLoopGroup-2-1] DEBUG io.netty.handler.logging.LoggingHandler - [id: 0xbd82013a, L:/127.0.0.1:54476 - R:/127.0.0.1:8000] WRITE: 181B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000010| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000020| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000030| 30 30 30 30 30 30 30 30 30 30 30 0a 30 30 30 30 |00000000000.0000|
|00000040| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000050| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000060| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000070| 0a 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |.000000000000000|
|00000080| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000090| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|000000a0| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|000000b0| 30 30 30 30 0a                                  |0000.           |
+--------+-------------------------------------------------+----------------+
16:41:27.624 [nioEventLoopGroup-2-1] DEBUG io.netty.handler.logging.LoggingHandler - [id: 0xbd82013a, L:/127.0.0.1:54476 - R:/127.0.0.1:8000] FLUSH

服务端

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package com.redisc;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.LineBasedFrameDecoder;
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 LineBasedFrameDecoder(1024));
                    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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16:41:27.735 [nioEventLoopGroup-3-1] DEBUG io.netty.handler.logging.LoggingHandler - [id: 0x9d3a3621, L:/127.0.0.1:8000 - R:/127.0.0.1:54476] READ: 59B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000010| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000020| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000030| 30 30 30 30 30 30 30 30 30 30 30                |00000000000     |
+--------+-------------------------------------------------+----------------+
16:41:27.735 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded inbound message PooledSlicedByteBuf(ridx: 0, widx: 59, cap: 59/59, unwrapped: PooledUnsafeDirectByteBuf(ridx: 60, widx: 181, cap: 2048)) that reached at the tail of the pipeline. Please check your pipeline configuration.
16:41:27.736 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded message pipeline : [LineBasedFrameDecoder#0, LoggingHandler#0, DefaultChannelPipeline$TailContext#0]. Channel : [id: 0x9d3a3621, L:/127.0.0.1:8000 - R:/127.0.0.1:54476].
16:41:27.736 [nioEventLoopGroup-3-1] DEBUG io.netty.handler.logging.LoggingHandler - [id: 0x9d3a3621, L:/127.0.0.1:8000 - R:/127.0.0.1:54476] READ: 52B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000010| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000020| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000030| 30 30 30 30                                     |0000            |
+--------+-------------------------------------------------+----------------+
16:41:27.737 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded inbound message PooledSlicedByteBuf(ridx: 0, widx: 52, cap: 52/52, unwrapped: PooledUnsafeDirectByteBuf(ridx: 113, widx: 181, cap: 2048)) that reached at the tail of the pipeline. Please check your pipeline configuration.
16:41:27.737 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded message pipeline : [LineBasedFrameDecoder#0, LoggingHandler#0, DefaultChannelPipeline$TailContext#0]. Channel : [id: 0x9d3a3621, L:/127.0.0.1:8000 - R:/127.0.0.1:54476].
16:41:27.737 [nioEventLoopGroup-3-1] DEBUG io.netty.handler.logging.LoggingHandler - [id: 0x9d3a3621, L:/127.0.0.1:8000 - R:/127.0.0.1:54476] READ: 67B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000010| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000020| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000030| 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
|00000040| 30 30 30                                        |000             |
+--------+-------------------------------------------------+----------------+
16:41:27.737 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded inbound message PooledSlicedByteBuf(ridx: 0, widx: 67, cap: 67/67, unwrapped: PooledUnsafeDirectByteBuf(ridx: 181, widx: 181, cap: 2048)) that reached at the tail of the pipeline. Please check your pipeline configuration.
16:41:27.738 [nioEventLoopGroup-3-1] DEBUG io.netty.channel.DefaultChannelPipeline - Discarded message pipeline : [LineBasedFrameDecoder#0, LoggingHandler#0, DefaultChannelPipeline$TailContext#0]. Channel : [id: 0x9d3a3621, L:/127.0.0.1:8000 - R:/127.0.0.1:54476].
16:41:27.738 [nioEventLoopGroup-3-1] DEBUG io.netty.handler.logging.LoggingHandler - [id: 0x9d3a3621, L:/127.0.0.1:8000 - R:/127.0.0.1:54476] READ COMPLETE
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