Netty通信中的粘包半包问题(二)

news2024/11/17 10:24:28

在前面我们已经分析过Netty会出现的粘包半包问题，还没看过前面的博客的，可以先去看下之前写的博客
Netty通信中的粘包半包问题(一)
解放方式:特殊分隔符解决,在每个报文后面加上一个特殊分隔符，以此来告诉服务端每个报文的数据结界是什么

1.Server

package splicing.delimiter;

import constant.Constant;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.Channel;
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.nio.NioServerSocketChannel;
import io.netty.handler.codec.DelimiterBasedFrameDecoder;

import java.net.InetSocketAddress;

public class DelimiterEchoServer {
    
    public static final String DELIMITER_SYMBOL = "@~";

    public static void main(String[] args) throws InterruptedException {
        DelimiterEchoServer delimiterEchoServer = new DelimiterEchoServer();
        System.out.println("服务器即将启动");
        delimiterEchoServer.start();
    }
    
    public void start() throws InterruptedException {
        DelimiterServerHandler serverHandler = new DelimiterServerHandler();
        // 线程组
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            // 服务端启动必须
            ServerBootstrap b = new ServerBootstrap();
            b.group(group)// 线程组传入
                    .channel(NioServerSocketChannel.class) // 指定使用NIO进行网络传输
                    .localAddress(new InetSocketAddress(Constant.DEFAULT_PORT)) //指定服务器监听端口
                    // 服务端没接收到一个连接请求，就会重启一个socket通信，也就是channel
                    // 所以下面这段代码的作用就是为这个子channel增加handler
                    .childHandler(new ChannelInitializerImp());

            ChannelFuture f = b.bind().sync();
            System.out.println("服务器启动完成，等待客户端的连接和数据....");
            // 阻塞直到服务器的channel关闭
            f.channel().closeFuture().sync();
        } finally {
            // 优雅关闭线程组
            group.shutdownGracefully().sync();
        }
    }
    
    private static class ChannelInitializerImp extends ChannelInitializer<Channel> {
        @Override
        protected void initChannel(Channel channel) throws Exception {
            ByteBuf delimiter = Unpooled.copiedBuffer(DELIMITER_SYMBOL.getBytes());
            channel.pipeline().addLast(new DelimiterBasedFrameDecoder(1024, delimiter));
            channel.pipeline().addLast(new DelimiterServerHandler());
        }
    }
}

package splicing.delimiter;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;

import java.util.concurrent.atomic.AtomicInteger;

public class DelimiterServerHandler extends ChannelInboundHandlerAdapter {
    
    private AtomicInteger counter = new AtomicInteger(0);

    /**
     * 服务端读取到网络数据后的处理
     */
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf in = (ByteBuf)msg;
        String request = in.toString(CharsetUtil.UTF_8);
        System.out.println("Server Accept[" + request 
                + "] and counter is :" + counter.incrementAndGet());
        
        String resp = "Hello," + request 
                + ". Welcome to Netty World!" 
                + DelimiterEchoServer.DELIMITER_SYMBOL;
        ctx.writeAndFlush(Unpooled.copiedBuffer(resp.getBytes()));
//        super.channelRead(ctx, msg);
    }

    /**
     * 服务端读取完成网络数据后的处理
     */
    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
//        super.channelReadComplete(ctx);

        System.out.println("channelReadComplete-------");
//        ctx.close();
    }

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

2.Client

package splicing.delimiter;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.util.CharsetUtil;

import java.util.concurrent.atomic.AtomicInteger;

public class DelimiterClientHandler extends SimpleChannelInboundHandler<ByteBuf> {
    
    private AtomicInteger counter = new AtomicInteger(0);

    /**
     * 客户端读取到网络数据后的处理
     */
    @Override
    protected void channelRead0(ChannelHandlerContext channelHandlerContext, ByteBuf msg) throws Exception {
        System.out.println("client Accept[" + msg.toString(CharsetUtil.UTF_8) 
                + "] and the counter is :" + counter.incrementAndGet());
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        ByteBuf msg = null;
        String request = "Mark,Zhuge,Zhouyu,fox,loulan" + DelimiterEchoServer.DELIMITER_SYMBOL;
//        super.channelActive(ctx);
        for (int i = 0; i < 100; i++) {
            
            msg = Unpooled.buffer(request.length());
            msg.writeBytes(request.getBytes());
            ctx.writeAndFlush(msg);
            System.out.println("发送数据到服务器");
        }
    }
}

package splicing.delimiter;

import constant.Constant;
import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.Channel;
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.nio.NioSocketChannel;
import io.netty.handler.codec.DelimiterBasedFrameDecoder;
import netscape.security.UserTarget;

import java.net.InetSocketAddress;

public class DelimiterEchoClient {
    
    private final String host;
    
    public DelimiterEchoClient(String host) {
        this.host = host;
    }
    
    public void start() throws InterruptedException {
        // 线程组
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group)// 将线程组传入
                    .channel(NioSocketChannel.class) // 使用指定NIO进行网络传输
                    .remoteAddress(new InetSocketAddress(host, Constant.DEFAULT_PORT)) //配置要连接服务器的ip地址和端口 
                    .handler(new ChannelInitializerImp());
            
            ChannelFuture f = b.connect().sync();
            System.out.println("已连接到服务器....");
            f.channel().closeFuture().sync();

        } finally {
            group.shutdownGracefully().sync();
        }
        
    }
    
    private static class ChannelInitializerImp extends ChannelInitializer<Channel> {
        @Override
        protected void initChannel(Channel channel) throws Exception {
            ByteBuf delimiter = 
                    Unpooled.copiedBuffer(DelimiterEchoServer.DELIMITER_SYMBOL.getBytes());
            channel.pipeline().addLast(new DelimiterBasedFrameDecoder(1024, delimiter));
            channel.pipeline().addLast(new DelimiterClientHandler());
        }
    }

    public static void main(String[] args) throws InterruptedException {
        new DelimiterEchoClient(Constant.DEFAULT_SERVER_IP).start();
    }
}