java - 如何在 Spring Integration DSL 中实现简单的 echo 套接字服务

Question

请，
您能帮助在 Spring Integration DSL 中实现一个简单的 echo 风格的 Heartbeat TCP 套接字服务吗？更准确地说，如何将 Adapter/Handler/Gateway 插入客户端和服务器端的 IntegrationFlows。 Spring Integration DSL 和 TCP/IP 客户端/服务器通信的实际示例很难找到。

我认为，我已经完成了大部分代码，只是将所有内容插入到 IntegrationFlow 中。

SI 示例中有一个示例 echo 服务，但它是用“旧”XML 配置编写的，我真的很难通过代码将其转换为配置。

我的心跳服务是一个简单的服务器，等待客户端询问“状态”，并以“确定”响应。

没有@ServiceActivator，没有@MessageGateways，没有代理，一切都明确而详细；由客户端的普通 JDK 调度执行器驱动；服务器和客户端位于单独的配置和项目中。

HeartbeatClientConfig

@Configuration
@EnableIntegration
public class HeartbeatClientConfig {

    @Bean
    public MessageChannel outboudChannel() {
        return new DirectChannel();
    }

    @Bean
    public PollableChannel inboundChannel() {
        return new QueueChannel();
    }

    @Bean
    public TcpNetClientConnectionFactory connectionFactory() {
        TcpNetClientConnectionFactory connectionFactory = new TcpNetClientConnectionFactory("localhost", 7777);
        return connectionFactory;
    }

    @Bean
    public TcpReceivingChannelAdapter heartbeatReceivingMessageAdapter(
            TcpNetClientConnectionFactory connectionFactory,
            MessageChannel inboundChannel) {
        TcpReceivingChannelAdapter heartbeatReceivingMessageAdapter = new TcpReceivingChannelAdapter();
        heartbeatReceivingMessageAdapter.setConnectionFactory(connectionFactory);
        heartbeatReceivingMessageAdapter.setOutputChannel(inboundChannel); // ???
        heartbeatReceivingMessageAdapter.setClientMode(true);
        return heartbeatReceivingMessageAdapter;
    }

    @Bean
    public TcpSendingMessageHandler heartbeatSendingMessageHandler(
            TcpNetClientConnectionFactory connectionFactory) {
        TcpSendingMessageHandler heartbeatSendingMessageHandler = new TcpSendingMessageHandler();
        heartbeatSendingMessageHandler.setConnectionFactory(connectionFactory);
        return heartbeatSendingMessageHandler;
    }

    @Bean
    public IntegrationFlow heartbeatClientFlow(
            TcpNetClientConnectionFactory connectionFactory,
            TcpReceivingChannelAdapter heartbeatReceivingMessageAdapter,
            TcpSendingMessageHandler heartbeatSendingMessageHandler,
            MessageChannel outboudChannel) {
        return IntegrationFlows
                .from(outboudChannel) // ??????
                .// adapter ???????????
                .// gateway ???????????
                .// handler ???????????
                .get();
    }

    @Bean
    public HeartbeatClient heartbeatClient(
            MessageChannel outboudChannel,
            PollableChannel inboundChannel) {
        return new HeartbeatClient(outboudChannel, inboundChannel);
    }
}

HeartbeatClient

public class HeartbeatClient {
    private final MessageChannel outboudChannel;
    private final PollableChannel inboundChannel;
    private final Logger log = LogManager.getLogger(HeartbeatClient.class);

    public HeartbeatClient(MessageChannel outboudChannel, PollableChannel inboundChannel) {
        this.inboundChannel = inboundChannel;
        this.outboudChannel = outboudChannel;
    }

    @EventListener
    public void initializaAfterContextIsReady(ContextRefreshedEvent event) {
        log.info("Starting Heartbeat client...");
        start();
    }

    public void start() {
        Executors.newSingleThreadScheduledExecutor().scheduleAtFixedRate(() -> {
            while (true) {
                try {
                    log.info("Sending Heartbeat");
                    outboudChannel.send(new GenericMessage<String>("status"));
                    Message<?> message = inboundChannel.receive(1000);
                    if (message == null) {
                        log.error("Heartbeat timeouted");
                    } else {
                        String messageStr = new String((byte[]) message.getPayload());
                        if (messageStr.equals("OK")) {
                            log.info("Heartbeat OK response received");
                        } else {
                            log.error("Unexpected message content from server: " + messageStr);
                        }
                    }
                } catch (Exception e) {
                    log.error(e);
                }
            }
        }, 0, 10000, TimeUnit.SECONDS);
    }
}

HeartbeatServerConfig

@Configuration
@EnableIntegration
public class HeartbeatServerConfig {

    @Bean
    public MessageChannel outboudChannel() {
        return new DirectChannel();
    }

    @Bean
    public PollableChannel inboundChannel() {
        return new QueueChannel();
    }

    @Bean
    public TcpNetServerConnectionFactory connectionFactory() {
        TcpNetServerConnectionFactory connectionFactory = new TcpNetServerConnectionFactory(7777);
        return connectionFactory;
    }

    @Bean
    public TcpReceivingChannelAdapter heartbeatReceivingMessageAdapter(
            TcpNetServerConnectionFactory connectionFactory,
            MessageChannel outboudChannel) {
        TcpReceivingChannelAdapter heartbeatReceivingMessageAdapter = new TcpReceivingChannelAdapter();
        heartbeatReceivingMessageAdapter.setConnectionFactory(connectionFactory);
        heartbeatReceivingMessageAdapter.setOutputChannel(outboudChannel);
        return heartbeatReceivingMessageAdapter;
    }

    @Bean
    public TcpSendingMessageHandler heartbeatSendingMessageHandler(
            TcpNetServerConnectionFactory connectionFactory) {
        TcpSendingMessageHandler heartbeatSendingMessageHandler = new TcpSendingMessageHandler();
        heartbeatSendingMessageHandler.setConnectionFactory(connectionFactory);
        return heartbeatSendingMessageHandler;
    }

    @Bean
    public IntegrationFlow heartbeatServerFlow(
            TcpReceivingChannelAdapter heartbeatReceivingMessageAdapter,
            TcpSendingMessageHandler heartbeatSendingMessageHandler,
            MessageChannel outboudChannel) {
        return IntegrationFlows
                .from(heartbeatReceivingMessageAdapter) // ???????????????
                .handle(heartbeatSendingMessageHandler) // ???????????????
                .get();
    }

    @Bean
    public HeartbeatServer heartbeatServer(
            PollableChannel inboundChannel, 
            MessageChannel outboudChannel) {
        return new HeartbeatServer(inboundChannel, outboudChannel);
    }
}

心跳服务器

public class HeartbeatServer {
    private final PollableChannel inboundChannel;
    private final MessageChannel outboudChannel;
    private final Logger log = LogManager.getLogger(HeartbeatServer.class);

    public HeartbeatServer(PollableChannel inboundChannel, MessageChannel outboudChannel) {
        this.inboundChannel = inboundChannel;
        this.outboudChannel = outboudChannel;
    }

    @EventListener
    public void initializaAfterContextIsReady(ContextRefreshedEvent event) {
        log.info("Starting Heartbeat");
        start();
    }

    public void start() {
        Executors.newSingleThreadExecutor().execute(() -> {
            while (true) {
                try {
                    Message<?> message = inboundChannel.receive(1000);
                    if (message == null) {
                        log.error("Heartbeat timeouted");
                    } else {
                        String messageStr = new String((byte[]) message.getPayload());
                        if (messageStr.equals("status")) {
                            log.info("Heartbeat received");
                            outboudChannel.send(new GenericMessage<>("OK"));
                        } else {
                            log.error("Unexpected message content from client: " + messageStr);
                        }
                    }
                } catch (Exception e) {
                    log.error(e);
                }
            }
        });
    }
}

奖励问题

为什么 channel 可以在TcpReceivingChannelAdapter(入站适配器)上设置，但不能在TcpSendingMessageHandler(出站适配器)上设置？

更新
如果有人有兴趣的话，这里是完整的项目源代码:
https://bitbucket.org/espinosa/spring-integration-tcp-demo
我会尝试将所有建议的解决方案放在那里。

Answer 1

使用 DSL 就简单多了...

@SpringBootApplication
@EnableScheduling
public class So55154418Application {

    public static void main(String[] args) {
        SpringApplication.run(So55154418Application.class, args);
    }

    @Bean
    public IntegrationFlow server() {
        return IntegrationFlows.from(Tcp.inboundGateway(Tcp.netServer(1234)))
                .transform(Transformers.objectToString())
                .log()
                .handle((p, h) -> "OK")
                .get();
    }

    @Bean
    public IntegrationFlow client() {
        return IntegrationFlows.from(Gate.class)
                .handle(Tcp.outboundGateway(Tcp.netClient("localhost", 1234)))
                .transform(Transformers.objectToString())
                .handle((p, h) -> {
                    System.out.println("Received:" + p);
                    return null;
                })
                .get();
    }

    @Bean
    @DependsOn("client")
    public Runner runner(Gate gateway) {
        return new Runner(gateway);
    }

    public static class Runner {

        private final Gate gateway;

        public Runner(Gate gateway) {
            this.gateway = gateway;
        }

        @Scheduled(fixedDelay = 5000)
        public void run() {
            this.gateway.send("foo");
        }

    }

    public interface Gate {

        void send(String out);

    }

}

或者，从 Gate 方法获取回复...

    @Bean
    public IntegrationFlow client() {
        return IntegrationFlows.from(Gate.class)
                .handle(Tcp.outboundGateway(Tcp.netClient("localhost", 1234)))
                .transform(Transformers.objectToString())
                .get();
    }

    @Bean
    @DependsOn("client")
    public Runner runner(Gate gateway) {
        return new Runner(gateway);
    }

    public static class Runner {

        private final Gate gateway;

        public Runner(Gate gateway) {
            this.gateway = gateway;
        }

        @Scheduled(fixedDelay = 5000)
        public void run() {
            String reply = this.gateway.sendAndReceive("foo"); // null for timeout
            System.out.println("Received:" + reply);
        }

    }

    public interface Gate {

        @Gateway(replyTimeout = 5000)
        String sendAndReceive(String out);

    }

奖金:

消费端点实际上由 2 个 bean 组成；消费者和消息处理程序。该 channel 面向消费者。请参阅here .

编辑

另一种选择，为客户端提供单个 bean...

@Bean
public IntegrationFlow client() {
    return IntegrationFlows.from(() -> "foo", 
                    e -> e.poller(Pollers.fixedDelay(Duration.ofSeconds(5))))
            .handle(Tcp.outboundGateway(Tcp.netClient("localhost", 1234)))
            .transform(Transformers.objectToString())
            .handle((p, h) -> {
                System.out.println("Received:" + p);
                return null;
            })
            .get();
}