<!--lombok-->
<dependency>
  <groupId>org.projectlombok</groupId>
  <artifactId>lombok</artifactId>
  <version>1.18.2</version>
  <optional>true</optional>
</dependency>

<!--netty-->
<dependency>
  <groupId>io.netty</groupId>
  <artifactId>netty-all</artifactId>
  <version>4.1.17.Final</version>
</dependency>

@Slf4j
public class NettyServer {
    public void start() {
        InetSocketAddress socketAddress = new InetSocketAddress("127.0.0.1", 8082);
        //new 一個主線程組
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        //new 一個工作線程組
        EventLoopGroup workGroup = new NioEventLoopGroup(200);
        ServerBootstrap bootstrap = new ServerBootstrap()
                .group(bossGroup, workGroup)
                .channel(NioServerSocketChannel.class)
                .childHandler(new ServerChannelInitializer())
                .localAddress(socketAddress)
                //設置隊列大小
                .option(ChannelOption.SO_BACKLOG, 1024)
                // 兩小時內沒有數(shù)據(jù)的通信時,TCP會自動發(fā)送一個活動探測數(shù)據(jù)報文
                .childOption(ChannelOption.SO_KEEPALIVE, true);
        //綁定端口,開始接收進來的連接
        try {
            ChannelFuture future = bootstrap.bind(socketAddress).sync();
            log.info("服務器啟動開始監(jiān)聽端口: {}", socketAddress.getPort());
            future.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            log.error("服務器開啟失敗", e);
        } finally {
            //關閉主線程組
            bossGroup.shutdownGracefully();
            //關閉工作線程組
            workGroup.shutdownGracefully();
        }
    }
}

/**
* netty服務初始化器
**/
public class ServerChannelInitializer extends ChannelInitializer<SocketChannel> {
    @Override
    protected void initChannel(SocketChannel socketChannel) throws Exception {
        //添加編解碼
        socketChannel.pipeline().addLast("decoder", new StringDecoder(CharsetUtil.UTF_8));
        socketChannel.pipeline().addLast("encoder", new StringEncoder(CharsetUtil.UTF_8));
        socketChannel.pipeline().addLast(new NettyServerHandler());
    }
}

/**
* netty服務端處理器
**/
@Slf4j
public class NettyServerHandler extends ChannelInboundHandlerAdapter {
    /**
     * 客戶端連接會觸發(fā)
     */
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        log.info("Channel active......");
    }

    /**
     * 客戶端發(fā)消息會觸發(fā)
     */
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        log.info("服務器收到消息: {}", msg.toString());
        ctx.write("你也好哦");
        ctx.flush();
    }

    /**
     * 發(fā)生異常觸發(fā)
     */
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }
}

/**
* 啟動類
*
*/
@Slf4j
@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
public class RpcServerApp extends SpringBootServletInitializer {
    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(RpcServerApp.class);
    }

    /**
     * 項目的啟動方法
     *
     * @param args
     */
    public static void main(String[] args) {
        SpringApplication.run(RpcServerApp.class, args);
        //開啟Netty服務
        NettyServer nettyServer =new  NettyServer ();
        nettyServer.start();
        log.info("======服務已經(jīng)啟動========");
    }
}

/**
* Netty客戶端
**/
@Slf4j
public class NettyClientUtil {

    public static ResponseResult helloNetty(String msg) {
        NettyClientHandler nettyClientHandler = new NettyClientHandler();
        EventLoopGroup group = new NioEventLoopGroup();
        Bootstrap bootstrap = new Bootstrap()
                .group(group)
                //該參數(shù)的作用就是禁止使用Nagle算法，使用于小數(shù)據(jù)即時傳輸
                .option(ChannelOption.TCP_NODELAY, true)
                .channel(NioSocketChannel.class)
                .handler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    protected void initChannel(SocketChannel socketChannel) throws Exception {
                        socketChannel.pipeline().addLast("decoder", new StringDecoder());
                        socketChannel.pipeline().addLast("encoder", new StringEncoder());
                        socketChannel.pipeline().addLast(nettyClientHandler);
                    }
                });
        try {
            ChannelFuture future = bootstrap.connect("127.0.0.1", 8082).sync();
            log.info("客戶端發(fā)送成功....");
            //發(fā)送消息
            future.channel().writeAndFlush(msg);
            // 等待連接被關閉
            future.channel().closeFuture().sync();
            return nettyClientHandler.getResponseResult();
        } catch (Exception e) {
            log.error("客戶端Netty失敗", e);
            throw new BusinessException(CouponTypeEnum.OPERATE_ERROR);
        } finally {
            //以一種優(yōu)雅的方式進行線程退出
            group.shutdownGracefully();
        }
    }
}

/**
* 客戶端處理器
**/
@Slf4j
@Setter
@Getter
public class NettyClientHandler extends ChannelInboundHandlerAdapter {

    private ResponseResult responseResult;

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        log.info("客戶端Active .....");
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        log.info("客戶端收到消息: {}", msg.toString());
        this.responseResult = ResponseResult.success(msg.toString(), CouponTypeEnum.OPERATE_SUCCESS.getCouponTypeDesc());
        ctx.close();
    }

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

@RestController
@Slf4j
public class UserController {

    @PostMapping("/helloNetty")
    @MethodLogPrint
    public ResponseResult helloNetty(@RequestParam String msg) {
        return NettyClientUtil.helloNetty(msg);
    }
}