Netty进阶——粘包与半包（短链接方式解决粘包问题）

Posted 2022-12-15 小志的博客

目录

• • 一、短链接方式解决粘包问题（代码示例）
  • • 1.1、短链接方式解决粘包问题的服务端代码示例
    • 1.2、短链接方式解决粘包问题的客户端代码示例
    • 1.3、分别启动服务端，客户端，查看服务端结果输出

一、短链接方式解决粘包问题（代码示例）

1.1、短链接方式解决粘包问题的服务端代码示例

• 服务端代码示例

  package com.example.nettytest.netty.day5;
  
  import io.netty.bootstrap.ServerBootstrap;
  import io.netty.channel.*;
  import io.netty.channel.nio.NioEventLoopGroup;
  import io.netty.channel.socket.SocketChannel;
  import io.netty.channel.socket.nio.NioserverSocketChannel;
  import io.netty.handler.logging.LogLevel;
  import io.netty.handler.logging.LoggingHandler;
  import lombok.extern.slf4j.Slf4j;
  /**
   * @description: 短链接方式解决粘包 问题服务端示例
   * @author: xz
   */
  @Slf4j
  public class NettyShortConnectServer 
      public static void main(String[] args) 
          new NettyServerTest().start();
      
  
      void start() 
          NioEventLoopGroup boss = new NioEventLoopGroup(1);
          NioEventLoopGroup worker = new NioEventLoopGroup();
          try 
              ServerBootstrap serverBootstrap = new ServerBootstrap()
                      .channel(NioServerSocketChannel.class)
                      .group(boss, worker)
                      .childHandler(new ChannelInitializer<SocketChannel>() 
                          @Override
                          protected void initChannel(SocketChannel ch) throws Exception 
                              ch.pipeline().addLast(new LoggingHandler(LogLevel.DEBUG));
                              ch.pipeline().addLast(new ChannelInboundHandlerAdapter() 
                                  //会在连接channel建立成功后，触发active事件
                                  @Override
                                  public void channelActive(ChannelHandlerContext ctx) throws Exception 
                                      log.debug("connected>>>>>>>>>>>>>>>> ", ctx.channel());
                                      super.channelActive(ctx);
                                  
                                  @Override
                                  public void channelInactive(ChannelHandlerContext ctx) throws Exception 
                                      log.debug("disconnect>>>>>>>>>>>>>>>> ", ctx.channel());
                                      super.channelInactive(ctx);
                                  
                              );
                          
                      );
              ChannelFuture channelFuture = serverBootstrap.bind(8080);
              log.debug(">>>>>>>>>>>>>>>> binding...", channelFuture.channel());
              channelFuture.sync();
              log.debug(">>>>>>>>>>>>>>>> bound...", channelFuture.channel());
              channelFuture.channel().closeFuture().sync();
           catch (InterruptedException e) 
              log.error("server error", e);
           finally 
              boss.shutdownGracefully();
              worker.shutdownGracefully();
              log.debug(">>>>>>>>>>>>>>>>stoped");
          
      
  
  

1.2、短链接方式解决粘包问题的客户端代码示例

• 客户端代码示例

  package com.example.nettytest.netty.day5;
  
  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;
  
  /**
   * @description: 短链接方式解决粘包 问题客户端示例
   * @author: xz
   */
  @Slf4j
  public class NettyShortConnectClient 
      public static void main(String[] args) 
          //1、分 3 次发送
          for (int i=0;i<3;i++)
              send();
          
      
  
      private static void send() 
          NioEventLoopGroup worker = new NioEventLoopGroup();
          try 
              Bootstrap bootstrap = new Bootstrap()
                  .channel(NioSocketChannel.class)
                  .group(worker)
                  .handler(new ChannelInitializer<SocketChannel>() 
                      @Override
                      protected void initChannel(SocketChannel ch) throws Exception 
                          log.debug("conneted》》》》》》》》");
                          ch.pipeline().addLast(new LoggingHandler(LogLevel.DEBUG));
                          ch.pipeline().addLast(new ChannelInboundHandlerAdapter() 
                              @Override
                              public void channelActive(ChannelHandlerContext ctx) throws Exception 
                                  log.debug("sending》》》》》》》》");
                                  ByteBuf buffer = ctx.alloc().buffer();
                                  buffer.writeBytes(new byte[]0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
                                  ctx.writeAndFlush(buffer);
                                  //2、发完即关
                                  ctx.close();
                              
                          );
                      
                  );
              ChannelFuture channelFuture = bootstrap.connect("localhost", 8080).sync();
              channelFuture.channel().closeFuture().sync();
           catch (InterruptedException e) 
              log.error("client error", e);
           finally 
              //3、关闭NioEventLoopGroup线程
              worker.shutdownGracefully();
          
      
  
  

1.3、分别启动服务端，客户端，查看服务端结果输出

• 先启动服务端
  

• 再启动客户端
  

• 再次查看服务端
  注：可下图输出结果可知：以短链接的方式，发一个包建立一次连接，这样连接建立到连接断开之间就是消息的边界，解决了粘包问题，但是缺点是效率太低。