Question

我正在使用4个分区的iot集线器上https://docs.microsoft.com/en-us/azure/iot-hub/iot-hub-java-java-getstarted上尝试java入门示例。

我通过创建1个客户端实例并为每个分区调用client.createReceiver来调整接收事件的部分，如下所示：

public class App {

  private static String connStr = "...";

  public static void main(String[] args) throws IOException, EventHubException, ExecutionException, InterruptedException {

    EventHubClient client = createClient();
    String[] partitionIds = client.getRuntimeInformation()
            .thenApply(eventHubRuntimeInformation -> eventHubRuntimeInformation.getPartitionIds())
            .get();

    client.createReceiver(DEFAULT_CONSUMER_GROUP_NAME, "0", Instant.now())
            .thenAccept(receiverHandler("0"));
    client.createReceiver(DEFAULT_CONSUMER_GROUP_NAME, "1", Instant.now())
            .thenAccept(receiverHandler("0"));
    client.createReceiver(DEFAULT_CONSUMER_GROUP_NAME, "2", Instant.now())
            .thenAccept(receiverHandler("2"));
    client.createReceiver(DEFAULT_CONSUMER_GROUP_NAME, "3", Instant.now())
            .thenAccept(receiverHandler("3"));


    System.out.println("Press ENTER to exit.");
    System.in.read();
    try {
        client.closeSync();
        System.exit(0);
    } catch (Exception e) {
        System.exit(1);
    }

  }

  private static Consumer<PartitionReceiver> receiverHandler(String partitionId) {
    return receiver -> {
        System.out.println("** Created receiver on partition " + partitionId);
        try {
            while (true) {
                receiver.receive(10)
                        .thenAccept(receivedEvents -> {
                                    int batchSize = 0;
                                    if (receivedEvents != null) {
                                        System.out.println("Got some evenst");
                                        for (EventData receivedEvent : receivedEvents) {
                                            System.out.println(String.format("Offset: %s, SeqNo: %s, EnqueueTime: %s",
                                                    receivedEvent.getSystemProperties().getOffset(),
                                                    receivedEvent.getSystemProperties().getSequenceNumber(),
                                                    receivedEvent.getSystemProperties().getEnqueuedTime()));
                                            System.out.println(String.format("| Device ID: %s",
                                                    receivedEvent.getSystemProperties().get("iothub-connection-device-id")));
                                            System.out.println(String.format("| Message Payload: %s",
                                                    new String(receivedEvent.getBytes(), Charset.defaultCharset())));
                                            batchSize++;
                                        }
                                    }
                                    System.out.println(String.format("Partition: %s, ReceivedBatch Size: %s", partitionId, batchSize));
                                }
                        ).get();

            }
        } catch (Exception e) {
            System.out.println("Failed to receive messages: " + e.getMessage());
        }
    };
  }

  private static EventHubClient createClient() {
    EventHubClient client = null;
    try {
        client = EventHubClient.createFromConnectionStringSync(connStr);
    } catch (Exception e) {
        System.out.println("Failed to create client: " + e.getMessage());
        System.exit(1);
    }
    return client;
  }
}

从模拟设备发送的事件碰巧到达分区3。问题是在以下情况下没有收到任何事件：

设备在启动事件接收器时未发送事件
设备在启动事件接收器时发送事件，但之后重新启动。在这种情况下，上述代码会在设备重启后停止接收事件

当我们只连接到分区3时，不会发生上述问题当我们只连接到分区3和另一个分区时，不会出现上述问题当我们连接到分区3和2或3个其他分区时，会发生上述问题。

任何线索？

Answer 1

当我们连接到分区3和2时，会发生上述问题 3个其他分区。

我使用您的代码失败并出现此错误“-source 1.5 java中不支持lambda表达式。”

然后我编辑the tutorial中的示例代码并启用一个客户端连接到四个分区接收器（这里有四个设备事件放在三个分区中，而不是四个，因为device1和device2的事件都放在partition2中。）：

public class App 
{
    private static String connStr = "Endpoint=sb://iothub-ns-ritatestio-265731-93e2a49f65.servicebus.windows.net/;EntityPath=ritatestiothub;SharedAccessKeyName=iothubowner;SharedAccessKey=z+QM62TftPlTfwS3CnN9348X2cmMkCaEFaC1IqYpiW8=";
    private static EventHubClient client = null;

    public static void main( String[] args ) throws IOException
    {       
        try {
          client = EventHubClient.createFromConnectionStringSync(connStr);
        } catch (Exception e) {
          System.out.println("Failed to create client: " + e.getMessage());
          System.exit(1);
        }

        // Create receivers for partitions 0 and 1.
        receiveMessages("0");
        receiveMessages("1");
        receiveMessages("2");
        receiveMessages("3");
        System.out.println("Press ENTER to exit.");

        System.in.read();
        try {
          client.closeSync();
          System.exit(0);
        } catch (Exception e) {
          System.exit(1);
        }
    }

    // Create a receiver on a partition.
private static void receiveMessages(final String partitionId) {
  try {
    // Create a receiver using the
    // default Event Hubs consumer group
    // that listens for messages from now on.
    client.createReceiver(EventHubClient.DEFAULT_CONSUMER_GROUP_NAME, partitionId, Instant.now())
      .thenAccept(new Consumer<PartitionReceiver>() {
        public void accept(PartitionReceiver receiver) {
          System.out.println("** Created receiver on partition " + partitionId);
          try {
            while (true) {
              Iterable<EventData> receivedEvents = receiver.receive(100).get();

              int batchSize = 0;
              if (receivedEvents != null) {
                for (EventData receivedEvent : receivedEvents) {
                  batchSize++;
                  System.out.println(String.format("Partition: %s, ReceivedBatch Size: %s, Device ID: %s, SeqNo: %s", partitionId, batchSize,receivedEvent.getSystemProperties().get("iothub-connection-device-id"),receivedEvent.getSystemProperties().getSequenceNumber()));
                }
              }

            }
          } catch (Exception e) {
            System.out.println("Failed to receive messages: " + e.getMessage());
          }
        }
      });
    } catch (Exception e) {
      System.out.println("Failed to create receiver: " + e.getMessage());
  }

}
}

设备重启后，我可以让三个分区接收器接收事件。您可以查看以下快照：

更新：将4台设备更改为1台要发送的设备。仍然，接收器可以在设备重启后继续接收消息。

侦听超过2个分区时，Java EventHubClient不会收到事件

1 个答案: