Netty从入门到秃头： websocket

1. 核心依赖

    
    
        io.netty
        netty-all
        4.1.6.Final
    

2. 代码

2.1 启动项

public class NioWebSocketServer {
    private final Logger logger=Logger.getLogger(this.getClass());
    private void init(){
        logger.info("正在启动websocket服务器");
        NioEventLoopGroup boss=new NioEventLoopGroup();
        NioEventLoopGroup work=new NioEventLoopGroup();
        try {
            ServerBootstrap bootstrap=new ServerBootstrap();
            bootstrap.group(boss,work);
            bootstrap.channel(NioServerSocketChannel.class);
            bootstrap.childHandler(new NioWebSocketChannelInitializer());
            Channel channel = bootstrap.bind(8081).sync().channel();
            logger.info("webSocket服务器启动成功："+channel);
            channel.closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
            logger.info("运行出错："+e);
        }finally {
            boss.shutdownGracefully();
            work.shutdownGracefully();
            logger.info("websocket服务器已关闭");
        }
    }

    public static void main(String[] args) {
        new NioWebSocketServer().init();
    }
}

netty搭建的服务器基本上都是差不多的写法：

• 绑定主线程组和工作线程组，这部分对应架构图中的事件循环组
• 只有服务器才需要绑定端口，客户端是绑定一个地址
• 配置channel（数据通道）参数，重点就是ChannelInitializer的配置
• 以异步的方式启动，最后是结束关闭两个线程组

2.2 ChannelInitializer写法

public class NioWebSocketChannelInitializer extends ChannelInitializer {
    @Override
    protected void initChannel(SocketChannel ch) {
        ch.pipeline().addLast("logging",new LoggingHandler("DEBUG"));//设置log监听器，并且日志级别为debug，方便观察运行流程
        ch.pipeline().addLast("http-codec",new HttpServerCodec());//设置解码器
        ch.pipeline().addLast("aggregator",new HttpObjectAggregator(65536));//聚合器，使用websocket会用到
        ch.pipeline().addLast("http-chunked",new ChunkedWriteHandler());//用于大数据的分区传输
        ch.pipeline().addLast("handler",new NioWebSocketHandler());//自定义的业务handler
    }
}

2.3 自定义的处理器NioWebSocketHandler

public class NioWebSocketHandler extends SimpleChannelInboundHandler