NIO（七）--Netty tcp粘包、拆包

 

方式一：分隔符

import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;

public class ServerHanlder extends ChannelHandlerAdapter {

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        String request = (String) msg;
        System.out.println("Server: " + request);
        String response = "888" + request + "$_";//服务端给客户端的响应
        ctx.writeAndFlush(Unpooled.copiedBuffer(response.getBytes()));
    }

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

import io.netty.bootstrap.ServerBootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.DelimiterBasedFrameDecoder;
import io.netty.handler.codec.string.StringDecoder;

public class Server {

    public static void main(String[] args) throws InterruptedException {

        EventLoopGroup bossGroup = new NioEventLoopGroup();         //一个用于处理服务器端接收客户端连接的
        EventLoopGroup workGroup = new NioEventLoopGroup();         //一个是进行网络通信的（网络读写的）
        ServerBootstrap b = new ServerBootstrap();                  //2创建辅助工具类，用于服务器通道的一系列配置
        b.group(bossGroup, workGroup)                               //绑定两个线程组
                .channel(NioServerSocketChannel.class)              //指定NIO的模式
                .option(ChannelOption.SO_BACKLOG, 1024)             //设置tcp缓冲区
                .option(ChannelOption.SO_SNDBUF, 32 * 1024)         //设置发送缓冲大小
                .option(ChannelOption.SO_RCVBUF, 32 * 1024)         //这是接收缓冲大小
                .option(ChannelOption.SO_KEEPALIVE, true)           //保持连接
                .childHandler(new ChannelInitializer() {
                    @Override
                    protected void initChannel(SocketChannel sc) throws Exception {

                        //设置特殊分隔符
                        ByteBuf buf = Unpooled.copiedBuffer("$_".getBytes());
                        sc.pipeline().addLast(new DelimiterBasedFrameDecoder(1024, buf));

                        //设置字符串形式的解码
                        sc.pipeline().addLast(new StringDecoder());
                        sc.pipeline().addLast(new ServerHanlder()); //3.在这里配置具体数据接收方法的处理
                    }
                });

        ChannelFuture cf1 = b.bind(6666).sync();                    //4.进行绑定

        cf1.channel().closeFuture().sync();                         //5.等待关闭

        bossGroup.shutdownGracefully();
        workGroup.shutdownGracefully();
    }
}

import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
import io.netty.util.ReferenceCountUtil;

public class ClientHandler extends ChannelHandlerAdapter {

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("client channel active...");
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {

        try {
            String response = (String) msg;
            System.out.println("Client: " + response);
        } finally {
            ReferenceCountUtil.release(msg);
        }
    }

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

import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.DelimiterBasedFrameDecoder;
import io.netty.handler.codec.string.StringDecoder;

public class Client {
    public static void main(String[] args) throws InterruptedException {
        EventLoopGroup group = new NioEventLoopGroup();
        Bootstrap b = new Bootstrap();
        b.group(group)
                .channel(NioSocketChannel.class)
                .handler(new ChannelInitializer() {
                    @Override
                    protected void initChannel(SocketChannel sc) throws Exception {
                        ByteBuf buf = Unpooled.copiedBuffer("$_".getBytes());
                        sc.pipeline().addLast(new DelimiterBasedFrameDecoder(1024, buf));
                        sc.pipeline().addLast(new StringDecoder());
                        sc.pipeline().addLast(new ClientHandler());
                    }
                });

        ChannelFuture cf1 = b.connect("127.0.0.1", 6666).sync();

        cf1.channel().writeAndFlush(Unpooled.copiedBuffer("aaa$_".getBytes()));   //客户端发出数据
        cf1.channel().writeAndFlush(Unpooled.copiedBuffer("bbb$_".getBytes()));   //客户端发出数据
        cf1.channel().writeAndFlush(Unpooled.copiedBuffer("ccc$_".getBytes()));   //客户端发出数据

        cf1.channel().closeFuture().sync();
        group.shutdownGracefully();
    }
}

方式二：定长

import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;

public class ServerHanlder extends ChannelHandlerAdapter {

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        String request = (String) msg;
        System.out.println("Server: " + request);
        String response = request;//服务端给客户端的响应
        ctx.writeAndFlush(Unpooled.copiedBuffer(response.getBytes()));
    }

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

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
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.string.StringDecoder;

public class Server {

    public static void main(String[] args) throws InterruptedException {

        EventLoopGroup bossGroup = new NioEventLoopGroup();         //一个用于处理服务器端接收客户端连接的
        EventLoopGroup workGroup = new NioEventLoopGroup();         //一个是进行网络通信的（网络读写的）
        ServerBootstrap b = new ServerBootstrap();                  //2创建辅助工具类，用于服务器通道的一系列配置
        b.group(bossGroup, workGroup)                               //绑定两个线程组
                .channel(NioServerSocketChannel.class)              //指定NIO的模式
                .option(ChannelOption.SO_BACKLOG, 1024)             //设置tcp缓冲区
                .option(ChannelOption.SO_SNDBUF, 32 * 1024)         //设置发送缓冲大小
                .option(ChannelOption.SO_RCVBUF, 32 * 1024)         //这是接收缓冲大小
                .option(ChannelOption.SO_KEEPALIVE, true)           //保持连接
                .childHandler(new ChannelInitializer() {
                    @Override
                    protected void initChannel(SocketChannel sc) throws Exception {

                        //设置定长字符串接收
                        sc.pipeline().addLast(new FixedLengthFrameDecoder(5));
                        //设置字符串形式的解码
                        sc.pipeline().addLast(new StringDecoder());
                        sc.pipeline().addLast(new ServerHanlder()); //3.在这里配置具体数据接收方法的处理
                    }
                });

        ChannelFuture cf1 = b.bind(6666).sync();                    //4.进行绑定

        cf1.channel().closeFuture().sync();                         //5.等待关闭

        bossGroup.shutdownGracefully();
        workGroup.shutdownGracefully();
    }
}

import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
import io.netty.util.ReferenceCountUtil;

public class ClientHandler extends ChannelHandlerAdapter {

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("client channel active...");
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {

        try {
            String response = (String) msg;
            System.out.println("Client: " + response);
        } finally {
            ReferenceCountUtil.release(msg);
        }
    }

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

import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.FixedLengthFrameDecoder;
import io.netty.handler.codec.string.StringDecoder;

public class Client {
    public static void main(String[] args) throws InterruptedException {
        EventLoopGroup group = new NioEventLoopGroup();
        Bootstrap b = new Bootstrap();
        b.group(group)
                .channel(NioSocketChannel.class)
                .handler(new ChannelInitializer() {
                    @Override
                    protected void initChannel(SocketChannel sc) throws Exception {

                        sc.pipeline().addLast(new FixedLengthFrameDecoder(5));
                        sc.pipeline().addLast(new StringDecoder());
                        sc.pipeline().addLast(new ClientHandler());
                    }
                });

        ChannelFuture cf1 = b.connect("127.0.0.1", 6666).sync();

        cf1.channel().writeAndFlush(Unpooled.wrappedBuffer("aaaaabbbbb".getBytes()));   //客户端发出数据
        cf1.channel().writeAndFlush(Unpooled.copiedBuffer("ccccccc   ".getBytes()));   //客户端发出数据

        cf1.channel().closeFuture().sync();
        group.shutdownGracefully();
    }
}

实际工作中，字符串分割的方式用得多。

第3种就是netty自定义协议