传入消息在来自Azure服务总线主题订阅的侦听器之间进行分配

Question

我正在使用以下来自Microsoft portal的代码从Azure service bus主题/订阅发送和接收消息。代码运行良好。当我运行两个接收者代码实例时，消息会在两个接收者之间分配。10个发送和接收各5个。我只想知道如何在所有接收器中获取所有消息。

public class ServiceBusTopicSender 
{

static final Gson GSON = new Gson();

    public static void main(String[] args) throws Exception, ServiceBusException {
        // TODO Auto-generated method stub

        TopicClient sendClient;
        String connectionString = "Endpoint=sb://basicbus.servicebus.windows.net/;"
                                + "SharedAccessKeyName=RootManageSharedAccessKey;"
                                + "SharedAccessKey=xxxxxpxxxxxxxxxxxxxxxxxx/xxxxxxxxxx=";

        sendClient = new TopicClient(new ConnectionStringBuilder(connectionString, "basictopic"));       
        sendMessagesAsync(sendClient).thenRunAsync(() -> sendClient.closeAsync());
    }

    static CompletableFuture<Void> sendMessagesAsync(TopicClient sendClient) {
        List<HashMap<String, String>> data =
                GSON.fromJson(
                        "[" +
                                "{'name' = 'Einstein', 'firstName' = 'Albert'}," +
                                "{'name' = 'Heisenberg', 'firstName' = 'Werner'}," +
                                "{'name' = 'Curie', 'firstName' = 'Marie'}," +
                                "{'name' = 'Hawking', 'firstName' = 'Steven'}," +
                                "{'name' = 'Newton', 'firstName' = 'Isaac'}," +
                                "{'name' = 'Bohr', 'firstName' = 'Niels'}," +
                                "{'name' = 'Faraday', 'firstName' = 'Michael'}," +
                                "{'name' = 'Galilei', 'firstName' = 'Galileo'}," +
                                "{'name' = 'Kepler', 'firstName' = 'Johannes'}," +
                                "{'name' = 'Kopernikus', 'firstName' = 'Nikolaus'}" +
                                "]",
                        new TypeToken<List<HashMap<String, String>>>() {
                        }.getType());

        List<CompletableFuture> tasks = new ArrayList<>();
        for (int i = 0; i < data.size(); i++) {
            final String messageId = Integer.toString(i);
            Message message = new Message(GSON.toJson(data.get(i), Map.class).getBytes(UTF_8));
            message.setContentType("application/json");
            message.setLabel("Scientist");
            message.setMessageId(messageId);
            message.setTimeToLive(Duration.ofMinutes(2));           
            System.out.printf("Message sending: Id = %s\n", message.getMessageId());
            tasks.add(
                    sendClient.sendAsync(message).thenRunAsync(() -> {
                        System.out.printf("\tMessage acknowledged: Id = %s\n", message.getMessageId());
                    }));
        }
        return CompletableFuture.allOf(tasks.toArray(new CompletableFuture<?>[tasks.size()]));
    }
}

public class ServiceBusTopicReceiver 
{
static final Gson GSON = new Gson();

    public static void main(String[] args) throws Exception, ServiceBusException {

        String connectionString = "Endpoint=sb://basicbus.servicebus.windows.net/;"
                                + "SharedAccessKeyName=RootManageSharedAccessKey;"
                                + "SharedAccessKey=xxxxxpxxxxxxxxxxxxxxxxxx/xxxxxxxxxx=";

        SubscriptionClient subscription1Client = new SubscriptionClient(new ConnectionStringBuilder(connectionString, 
                "basictopic/subscriptions/basicsubscription"), ReceiveMode.PEEKLOCK);


        registerMessageHandlerOnClient(subscription1Client);

    }

    static void registerMessageHandlerOnClient(SubscriptionClient receiveClient) throws Exception {

        // register the RegisterMessageHandler callback
        IMessageHandler messageHandler = new IMessageHandler() {
            // callback invoked when the message handler loop has obtained a message
            public CompletableFuture<Void> onMessageAsync(IMessage message) {
                // receives message is passed to callback
                if (message.getLabel() != null &&
                        message.getContentType() != null &&
                        message.getLabel().contentEquals("Scientist") &&
                        message.getContentType().contentEquals("application/json")) {

                    byte[] body = message.getBody();
                    Map scientist = GSON.fromJson(new String(body, UTF_8), Map.class);

                System.out.printf(
                        "\n\t\t\t\t%s Message received: \n\t\t\t\t\t\tMessageId = %s, \n\t\t\t\t\t\tSequenceNumber = %s, \n\t\t\t\t\t\tEnqueuedTimeUtc = %s," +
                                "\n\t\t\t\t\t\tExpiresAtUtc = %s, \n\t\t\t\t\t\tContentType = \"%s\",  \n\t\t\t\t\t\tContent: [ firstName = %s, name = %s ]\n",
                        receiveClient.getEntityPath(),
                        message.getMessageId(),
                        message.getSequenceNumber(),
                        message.getEnqueuedTimeUtc(),
                        message.getExpiresAtUtc(),
                        message.getContentType(),
                        scientist != null ? scientist.get("firstName") : "",
                        scientist != null ? scientist.get("name") : "");
                System.out.println("Partition Key is ::::: " + message.getPartitionKey());
            }
            return receiveClient.completeAsync(message.getLockToken());
        }

        public void notifyException(Throwable throwable, ExceptionPhase exceptionPhase) {
            System.out.printf(exceptionPhase + "-" + throwable.getMessage());
        }
    };
    receiveClient.registerMessageHandler(
                messageHandler,
                // callback invoked when the message handler has an exception to report
            // 1 concurrent call, messages are auto-completed, auto-renew duration
            new MessageHandlerOptions(1, false, Duration.ofMinutes(1)));

}

}

Answer 1

Azure Service Bus是一个经纪人。当您接收消息时，您使用的是竞争消费者模式。这意味着，如果您有一个订阅，并且您的流程的多个实例侦听同一个订阅，它们将不会得到相同的消息。它们只会得到一个子集，这是其他实例没有接收到的。那是故意的。如果希望多个处理器实例接收相同的消息，则需要为每个处理器实例创建一个订阅。这样，发送到主题的每个消息都将复制到每个订阅，并且每个订阅者（接收者）都将获得自己的副本。