<!--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(shè)置隊列大小
        .option(ChannelOption.SO_BACKLOG, 1024)
        // 兩小時內(nèi)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(guān)閉主線程組
      bossGroup.shutdownGracefully();
      //關(guān)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(guān)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);
  }
}