netty长链接还是短链接 java代码实现

Netty支持长连接和短连接，具体采用哪种方式取决于你的应用场景和需求。下面是Java代码实现长连接和短连接的示例：

1. 长连接

public class LongConnectionServer {
    public static void main(String[] args) {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup)
             .channel(NioServerSocketChannel.class)
             .childHandler(new ChannelInitializer<SocketChannel>() {
                 @Override
                 public void initChannel(SocketChannel ch) throws Exception {
                     ch.pipeline().addLast(new LongConnectionHandler());
                 }
             })
             .option(ChannelOption.SO_BACKLOG, 128)
             .childOption(ChannelOption.SO_KEEPALIVE, true);

            ChannelFuture f = b.bind(8080).sync();

            f.channel().closeFuture().sync();
        } finally {
            workerGroup.shutdownGracefully();
            bossGroup.shutdownGracefully();
        }
    }
}

public class LongConnectionHandler extends ChannelInboundHandlerAdapter {
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        // 处理请求
        // ...

        // 返回响应
        ByteBuf resp = Unpooled.copiedBuffer("Hello World".getBytes());
        ctx.write(resp);
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.flush();
    }

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

2. 短连接

public class ShortConnectionServer {
    public static void main(String[] args) {
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group)
             .channel(NioSocketChannel.class)
             .handler(new ChannelInitializer<SocketChannel>() {
                 @Override
                 public void initChannel(SocketChannel ch) throws Exception {
                     ch.pipeline().addLast(new ShortConnectionHandler());
                 }
             });

            ChannelFuture f = b.connect("localhost", 8080).sync();

            // 发送请求
            ByteBuf req = Unpooled.copiedBuffer("Hello Server".getBytes());
            f.channel().writeAndFlush(req);

            f.channel().closeFuture().sync();
        } finally {
            group.shutdownGracefully();
        }
    }
}

public class ShortConnectionHandler extends ChannelInboundHandlerAdapter {
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf resp = (ByteBuf) msg;
        byte[] bytes = new byte[resp.readableBytes()];
        resp.readBytes(bytes);
        String respStr = new String(bytes);
        System.out.println("Server response: " + respStr);
        ctx.close();
    }

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

以上示例中，LongConnectionServer和LongConnectionHandler实现了长连接的服务端和处理器，ShortConnectionServer和ShortConnectionHandler实现了短连接的客户端和处理器。需要注意的是，长连接需要使用SO_KEEPALIVE选项来保持连接，短连接则不需要。