How to get the messageID

[azui007]

Please answer the following questions before submitting your doc issue. Thanks!

What issue do you find in Pulsar docs?

I want to know how to get the messageID
The docs does not describe this
can you help me?
thanks

What is your suggestion?

add the describe and demo

Do you have any references?

no

Would you like to fix this issue?

(Welcome to contribute docs! Pulsar grows from a tiny seed to a big tree with every little effort by us! Your contribution is the sunlight, water, and air!)

[hezhangjian]

What timing or phase do you want to get the messageID, consumer?

[BewareMyPower]

        try (PulsarClient client = PulsarClient.builder().serviceUrl("pulsar://localhost:6650").build()) {
            final String topic = "topic";
            final Consumer<byte[]> consumer = client.newConsumer()
                    .topic(topic)
                    .subscriptionName("sub")
                    .subscribe();
            final Producer<byte[]> producer = client.newProducer()
                    .topic(topic)
                    .create();
            final CountDownLatch latch = new CountDownLatch(1);
            producer.sendAsync("hello".getBytes(StandardCharsets.UTF_8)).whenComplete((id, e) -> {
                if (e == null) {
                    System.out.println("Send to " + id + ", type: " + id.getClass().getTypeName());
                }
                latch.countDown();
            });
            final Message<byte[]> message = consumer.receive();
            final MessageId id = message.getMessageId();
            System.out.println("Received from " + id + ", type: " + id.getClass());
            latch.await(); // wait until send callback is triggered
        } catch (PulsarClientException | InterruptedException e) {
            e.printStackTrace();
        }

[liangyuanpeng]

You can get the messageId when you send message success or received message.

[azui007]

What timing or phase do you want to get the messageID, consumer?

i want use this api: reset-cursor
the options need messageId

[azui007]

You can get the messageId when you send message success or received message.

How can i get the messageid on i received message.
Can you tell me which API I should use

[liangyuanpeng]

        try (PulsarClient client = PulsarClient.builder().serviceUrl("pulsar://localhost:6650").build()) {
            final String topic = "topic";
            final Consumer<byte[]> consumer = client.newConsumer()
                    .topic(topic)
                    .subscriptionName("sub")
                    .subscribe();
            final Producer<byte[]> producer = client.newProducer()
                    .topic(topic)
                    .create();
            final CountDownLatch latch = new CountDownLatch(1);
            producer.sendAsync("hello".getBytes(StandardCharsets.UTF_8)).whenComplete((id, e) -> {
                if (e == null) {
                    System.out.println("Send to " + id + ", type: " + id.getClass().getTypeName());
                }
                latch.countDown();
            });
            final Message<byte[]> message = consumer.receive();
            final MessageId id = message.getMessageId();
            System.out.println("Received from " + id + ", type: " + id.getClass());
            latch.await(); // wait until send callback is triggered
        } catch (PulsarClientException | InterruptedException e) {
            e.printStackTrace();
        }

@azui007 see consumer.receive();