使用netty实现多端口

使用Netty实现多端口可以通过创建多个ServerBootstrap实例，并分别绑定不同的端口。以下是一个示例代码：

public class MultiPortServer {
    private final int port1;
    private final int port2;

    public MultiPortServer(int port1, int port2) {
        this.port1 = port1;
        this.port2 = port2;
    }

    public void run() throws Exception {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b1 = new ServerBootstrap();
            b1.group(bossGroup, workerGroup)
              .channel(NioServerSocketChannel.class)
              .childHandler(new ChannelInitializer<SocketChannel>() {
                  @Override
                  public void initChannel(SocketChannel ch) throws Exception {
                      ch.pipeline().addLast(new MultiPortServerHandler("Port 1"));
                  }
              });

            ServerBootstrap b2 = new ServerBootstrap();
            b2.group(bossGroup, workerGroup)
              .channel(NioServerSocketChannel.class)
              .childHandler(new ChannelInitializer<SocketChannel>() {
                  @Override
                  public void initChannel(SocketChannel ch) throws Exception {
                      ch.pipeline().addLast(new MultiPortServerHandler("Port 2"));
                  }
              });

            b1.bind(port1).sync();
            b2.bind(port2).sync();
        } finally {
            workerGroup.shutdownGracefully();
            bossGroup.shutdownGracefully();
        }
    }

    public static void main(String[] args) throws Exception {
        int port1 = 8000;
        int port2 = 8001;
        new MultiPortServer(port1, port2).run();
    }
}

public class MultiPortServerHandler extends SimpleChannelInboundHandler<ByteBuf> {
    private final String serverName;

    public MultiPortServerHandler(String serverName) {
        this.serverName = serverName;
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) {
        System.out.println(serverName + " active");
    }

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, ByteBuf in) {
        System.out.println(serverName + " received: " + in.toString(CharsetUtil.UTF_8));
    }

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

在上述示例中，通过创建两个ServerBootstrap实例，并分别绑定不同的端口。同时，每个ServerBootstrap实例都配置了自己的ChannelHandler。在MultiPortServerHandler中，可以根据serverName来区分不同的端口。当有数据到来时，会打印出数据来源的端口信息。