本文共 4825 字，大约阅读时间需要 16 分钟。

1)服务端

ChatServer.java

package chat;import chat.handler.WSServerInitializer;import io.netty.bootstrap.ServerBootstrap;import io.netty.channel.ChannelFuture;import io.netty.channel.EventLoopGroup;import io.netty.channel.nio.NioEventLoopGroup;import io.netty.channel.socket.nio.NioServerSocketChannel;public class ChatServer {    public static void main(String[] args) {        EventLoopGroup bossGroup = new NioEventLoopGroup(1);        EventLoopGroup workerGroup = new NioEventLoopGroup();        try {            ServerBootstrap serverBootstrap = new ServerBootstrap();            serverBootstrap.group(bossGroup, workerGroup)                    .channel(NioServerSocketChannel.class)                    .childHandler(new WSServerInitializer());            int port = 8088;            ChannelFuture channelFuture = serverBootstrap.bind(port).sync();            System.out.println("聊天服务器启动成功 port:" + port);            channelFuture.channel().closeFuture().sync();        } catch (InterruptedException e) {            e.printStackTrace();        } finally {            bossGroup.shutdownGracefully();            workerGroup.shutdownGracefully();        }    }}

2)WSServerInitializer.java

package chat.handler;import io.netty.channel.ChannelInitializer;import io.netty.channel.ChannelPipeline;import io.netty.channel.socket.SocketChannel;import io.netty.handler.codec.http.HttpObjectAggregator;import io.netty.handler.codec.http.HttpServerCodec;import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;import io.netty.handler.stream.ChunkedWriteHandler;public class WSServerInitializer extends ChannelInitializer
   
     {    protected void initChannel(SocketChannel socketChannel) throws Exception {        ChannelPipeline pipeline = socketChannel.pipeline();        pipeline.addLast(new HttpServerCodec());        pipeline.addLast(new ChunkedWriteHandler());        pipeline.addLast(new HttpObjectAggregator(1024 * 64));        pipeline.addLast(new WebSocketServerProtocolHandler("/ws"));        // 业务Handler        pipeline.addLast(new ChatHandler());    }}
   

3)ChatHandler.java

package chat.handler;import io.netty.channel.ChannelHandlerContext;import io.netty.channel.SimpleChannelInboundHandler;import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;import java.time.LocalDateTime;import java.util.Map;import java.util.concurrent.ConcurrentHashMap;public class ChatHandler extends SimpleChannelInboundHandler
   
     {    // 存储所有的客户端    private static ConcurrentHashMap
    
      clientHashMap = new ConcurrentHashMap<>();    protected void channelRead0(ChannelHandlerContext channelHandlerContext, TextWebSocketFrame textWebSocketFrame) throws Exception {        String content = textWebSocketFrame.text();        for (ChannelHandlerContext key : clientHashMap.keySet()) {            ChannelHandlerContext ctx = key;            ctx.channel().writeAndFlush(new TextWebSocketFrame(LocalDateTime.now() + " " + channelHandlerContext.channel().remoteAddress() + "说: " + content));        }    }    @Override    public void channelActive(ChannelHandlerContext ctx) throws Exception {        System.out.println("客户端进来了:" + ctx.channel().remoteAddress());        clientHashMap.put(ctx, ctx);    }    @Override    public void channelInactive(ChannelHandlerContext ctx) throws Exception {        System.out.println("客户端断开连接:" + ctx.channel().remoteAddress());        clientHashMap.remove(ctx);    }    @Override    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {        System.out.println("客户端异常:" + ctx.channel().remoteAddress());        cause.printStackTrace();        ctx.close();    }}
    
   

pom.xml

   
       
    
     4.0.0
        
    
     org.example
        
        
    
     NettyChatRoom
        
    
     1.0
        
            
                 
                      
       
        org.apache.maven.plugins
                       
       
        maven-compiler-plugin
                       
                       
                           
        8                    
        
         8
                        
                   
                  
                      
       
        maven-assembly-plugin
                       
       
        3.3.0
                       
                           
                            
         
          
          
           chat.ChatServer
           
          
                            
         
         
          jar-with-dependencies
          
                            
                            
        
         false
                        
                       
                           
         
         
          make-assembly
          
          
         
          package
          
          
          
          
           single
           
          
                        
                   
              
         
        
            
                 
      
       io.netty
                  
      
       netty-all
                  
      
       4.1.32.Final
              
         
    
   

2)客户端

ChatClient.html

    
       
   
    发送消息：
   
   
    接受消息：