Netty客户端使用以及重连

1. pom依赖

<dependency>
    <groupId>io.netty</groupId>
	<artifactId>netty-all</artifactId>
	<version>4.1.30.Final</version>
</dependency>

2. 测试工具

链接：https://pan.baidu.com/s/1g64RpTcPwIgVFybcOFEJVA
提取码：ncz9

3. 代码实现

public class NettyClientUtil {

    static String[] ips = {"127.0.0.1"};
    static Integer port = 8886;
    static Bootstrap bootstrap;
    // 客户端就只需要创建一个 线程组了
    static EventLoopGroup loopGroup = new NioEventLoopGroup();

    public static void main(String[] args) {
        for (String ip : ips) {
            start(ip, port);
        }
    }

    public static void start(String ip, Integer port) {

        // 创建 启动器
        bootstrap = new Bootstrap();

        try {
            bootstrap.group(loopGroup)
                    .channel(NioSocketChannel.class)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel socketChannel) throws Exception {
                            socketChannel.pipeline().addLast(new IdleStateHandler(30, 0, 0, TimeUnit.SECONDS))
//                                    .addLast(new FixedLengthFrameDecoder(22)) //数据包的长度
                                    .addLast(new NettyClientHandler());
                        }
                    });
            // 连接服务
            ChannelFuture future = connect(ip, port);
            // 对服务关闭 监听
//            future.channel().closeFuture().sync();
        } catch (Exception e) {
            loopGroup.shutdownGracefully();
            System.out.println(e.getMessage());
        } /*finally {

        }*/

    }

    public static ChannelFuture connect(String ip, Integer port) {
        bootstrap.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 3000);
        ChannelFuture channelFuture = bootstrap.connect(ip, port).addListener(new ChannelFutureListener() {
            @Override
            public void operationComplete(ChannelFuture future) throws Exception {
                if (!future.isSuccess()) {
                    System.out.println(Thread.currentThread().getName() + ">>>>>连接" + ip + ":" + port + "服务端超时，1秒后重试……");
                    Thread.sleep(1000);
                    connect(ip, port);
                }
            }
        });
        return channelFuture;
    }
}

public class NettyClientHandler extends ChannelInboundHandlerAdapter {


    /**
     * 连接上服务的回调方法
     *
     * @param ctx
     * @throws Exception
     */
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        InetSocketAddress inetSocketAddress = (InetSocketAddress) ctx.channel().remoteAddress();
        // 发送数据
        System.out.println(Thread.currentThread().getName() + ">>>>>连接上了" +
                inetSocketAddress.getAddress().getHostAddress() + ":" + inetSocketAddress.getPort() + "服务端....");


    }

    /**
     * 读取服务端返回的信息
     *
     * @param ctx
     * @param msg
     * @throws Exception
     */
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf buf = (ByteBuf) msg;
        System.out.println(Thread.currentThread().getName() + ">>>>>" + buf.toString(CharsetUtil.UTF_8));

    }

    /**
     * 异常断开回调方法
     * 
     * @param ctx
     * @throws Exception
     */
    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        InetSocketAddress inetSocketAddress = (InetSocketAddress) ctx.channel().remoteAddress();
        String ip = inetSocketAddress.getAddress().getHostAddress();
        int port = inetSocketAddress.getPort();
        System.out.println(Thread.currentThread().getName() + ">>>>>与服务端" +
                ip + ":" + port + "断开连接，3秒后尝试重试连接……");
        Thread.sleep(3000);
        NettyClientUtil.connect(ip, port);
        super.channelInactive(ctx);
    }


}

4. 结果展示

连接服务端

服务端推送消息

关闭服务端

再次打开服务端