Netty解决粘包问题(2) 定长填充

第二种解决粘包的方案，就是每次发送固定长度的数据包，如果长度不够，那就用空字符串填充

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import java.nio.ByteBuffer;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.FixedLengthFrameDecoder;import io.netty.handler.codec.string.StringDecoder;import io.netty.handler.codec.string.StringEncoder;public class Server {    public static void main(String[] args) throws Exception{        //1 创建2个线程，一个是负责接收客户端的连接。一个是负责进行数据传输的        EventLoopGroup pGroup = new NioEventLoopGroup();        EventLoopGroup cGroup = new NioEventLoopGroup();        //2 创建服务器辅助类        ServerBootstrap b = new ServerBootstrap();        b.group(pGroup, cGroup)         .channel(NioServerSocketChannel.class)         .option(ChannelOption.SO_BACKLOG, 1024)         .option(ChannelOption.SO_SNDBUF, 32*1024)         .option(ChannelOption.SO_RCVBUF, 32*1024)         .childHandler(new ChannelInitializer<SocketChannel>() {            @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 ServerHandler());            }        });        //4 绑定连接        ChannelFuture cf = b.bind(8765).sync();        //等待服务器监听端口关闭        cf.channel().closeFuture().sync();        pGroup.shutdownGracefully();        cGroup.shutdownGracefully();    }}

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import io.netty.buffer.Unpooled;import io.netty.channel.ChannelHandlerAdapter;import io.netty.channel.ChannelHandlerContext;public class ServerHandler extends ChannelHandlerAdapter {    @Override    public void channelActive(ChannelHandlerContext ctx) throws Exception {        System.out.println(" server channel active... ");    }    @Override    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {        String request = (String)msg;        System.out.println("Server :" + msg);        String response =  request ;        ctx.writeAndFlush(Unpooled.copiedBuffer(response.getBytes()));    }    @Override    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {    }    @Override    public void exceptionCaught(ChannelHandlerContext ctx, Throwable t) throws Exception {    }}

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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.FixedLengthFrameDecoder;import io.netty.handler.codec.string.StringDecoder;import io.netty.handler.codec.string.StringEncoder;public class Client {    public static void main(String[] args) throws Exception {        EventLoopGroup group = new NioEventLoopGroup();        Bootstrap b = new Bootstrap();        b.group(group)         .channel(NioSocketChannel.class)         .handler(new ChannelInitializer<SocketChannel>() {            @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 cf = b.connect("127.0.0.1", 8765).sync();        cf.channel().writeAndFlush(Unpooled.wrappedBuffer("aaaaabbbbb".getBytes()));        cf.channel().writeAndFlush(Unpooled.copiedBuffer("ccccccc".getBytes()));        //等待客户端端口关闭        cf.channel().closeFuture().sync();        group.shutdownGracefully();    }}

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import io.netty.channel.ChannelHandlerAdapter;import io.netty.channel.ChannelHandlerContext;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 {        String response = (String)msg;        System.out.println("Client: " + response);    }    @Override    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {    }    @Override    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {    }}

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运行结果

//服务器端server channel active... Server :aaaaaServer :bbbbbServer :ccccc

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//客户端client channel active... Client: aaaaaClient: bbbbbClient: ccccc