解决半包粘包示例【固定长度解码器】

package com.io.netty.netty.netty13;

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 lombok.extern.slf4j.Slf4j;

import java.util.Arrays;
import java.util.Random;

@Slf4j
public class HelloWorldClient {

    public static StringBuilder makeString(char c, int len) {
        StringBuilder sb = new StringBuilder(len + 2);
        for (int i = 0; i < len; i++) {
            sb.append(c);
        }
        sb.append("\r\n");//空格符号
//        sb.append("\n");//换行符号
        return sb;
    }

    static void start() {
        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 ch) {
                    ch.pipeline().addLast(new LoggingHandler(LogLevel.DEBUG));
                    ch.pipeline().addLast(new ChannelInboundHandlerAdapter() {
                        @Override
                        public void channelActive(ChannelHandlerContext ctx) throws Exception {
                            ByteBuf buf=ctx.alloc().buffer();
                            char c = '0';
                            Random random = new Random();
                            for (int i = 0; i < 10; i++) {
                                StringBuilder stringBuilder = makeString(c, random.nextInt(256) + 1);
                                c++;
                                buf.writeBytes(stringBuilder.toString().getBytes());
                            }
                            ctx.writeAndFlush(buf);
                        }
                    });
                }
            });
            ChannelFuture localhost = bootstrap.connect("localhost", 9092).sync();
            localhost.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            log.debug("server error", e);
        } finally {
            worker.shutdownGracefully();
        }


    }

    public static void main(String[] args) {
            start();
    }
}

　　使用固定长度解码器:LineBasedFrameDecoder

package com.io.netty.netty.netty13;

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.codec.LineBasedFrameDecoder;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import lombok.extern.slf4j.Slf4j;

/**
 * 固定长度解码 LineBasedFrameDecoder  \n  \r\n
 */
@Slf4j
public class HelloWorldServer {

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

        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap.channel(NioServerSocketChannel.class);
            serverBootstrap.childOption(ChannelOption.RCVBUF_ALLOCATOR,//childOption针对的是每次channel连接
                    new AdaptiveRecvByteBufAllocator(16, 16, 16));//默认最新小64，默认初始化1024，默认最大65536
            serverBootstrap.group(boss, worker);
            serverBootstrap.childHandler(new ChannelInitializer<SocketChannel>() {
                @Override
                protected void initChannel(SocketChannel ch) {
                    ch.pipeline().addLast(new LineBasedFrameDecoder(1024));//超过这个长度还没有换行符就会失败
                    ch.pipeline().addLast(new LoggingHandler(LogLevel.DEBUG));

                }
            });
            ChannelFuture channelFuture = serverBootstrap.bind(9092).sync();
            channelFuture.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            log.debug("server error", e);
        } finally {
            boss.shutdownGracefully();
            worker.shutdownGracefully();
        }

    }
}