AWS SQS Java.并非所有消息都从SQS队列中检索

Question

我一直在尝试使用AWS SDK for Java从SQS队列中检索所有消息的几种方法无济于事.我已经了解了AWS SQS的分布式特性,并且消息存储在不同的服务器上.但我不明白为什么这个架构不会被最终用户隐藏.我需要在Java代码中应用哪些技巧来检索所有消息,并且100%确定没有人错过？

我试着用"长轮询":

ReceiveMessageRequest receiveMessageRequest = new ReceiveMessageRequest(myQueueUrl);
List<Message> messages = sqs.receiveMessage(receiveMessageRequest).getMessages();
for (Message message : messages) {
System.out.println(" Message");
System.out.println(" MessageId: " + message.getMessageId());
System.out.println(" ReceiptHandle: " + message.getReceiptHandle());
System.out.println(" MD5OfBody: " + message.getMD5OfBody());
System.out.println(" Body: " + message.getBody());
for (Entry<String, String> entry : message.getAttributes().entrySet()) {
System.out.println(" Attribute");
System.out.println(" Name: " + entry.getKey());
System.out.println(" Value: " + entry.getValue());
}
}
System.out.println();

这与请求批处理/客户端缓​​冲:

    // Create the basic Amazon SQS async client
    AmazonSQSAsync sqsAsync = new AmazonSQSAsyncClient();

    // Create the buffered client
    AmazonSQSAsync bufferedSqs = new AmazonSQSBufferedAsyncClient(sqsAsync);

    CreateQueueRequest createRequest = new CreateQueueRequest().withQueueName("MyTestQueue");

    CreateQueueResult res = bufferedSqs.createQueue(createRequest);

    SendMessageRequest request = new SendMessageRequest();
    String body = "test message_" + System.currentTimeMillis();
    request.setMessageBody( body );
    request.setQueueUrl(res.getQueueUrl());

    SendMessageResult sendResult = bufferedSqs.sendMessage(request);

    ReceiveMessageRequest receiveRq = new ReceiveMessageRequest()
    .withMaxNumberOfMessages(10)
    .withQueueUrl(queueUrl);
    ReceiveMessageResult rx = bufferedSqs.receiveMessage(receiveRq);

    List<Message> messages = rx.getMessages();
    for (Message message : messages) {
    System.out.println(" Message");
    System.out.println(" MessageId: " + message.getMessageId());
    System.out.println(" ReceiptHandle: " + message.getReceiptHandle());
    System.out.println(" MD5OfBody: " + message.getMD5OfBody());
    System.out.println(" Body: " + message.getBody());
    for (Entry<String, String> entry : message.getAttributes().entrySet()) {
    System.out.println(" Attribute");
    System.out.println(" Name: " + entry.getKey());
    System.out.println(" Value: " + entry.getValue());
    }
    }

但我仍然无法检索所有消息.

任何的想法？

AWS论坛对我的帖子保持沉默.

Answer 1

从SQS队列接收消息时,需要重复呼叫sqs:ReceiveMessage.

在每次调用时sqs:ReceiveMessage,您将从队列中获得0个或更多消息,您需要迭代这些消息.对于每条消息,您还需要sqs:DeleteMessage在处理完每条消息后调用以从队列中删除消息.

在上面的"长轮询"示例周围添加一个循环以接收所有消息.

for (;;) {
    ReceiveMessageRequest receiveMessageRequest = new ReceiveMessageRequest(myQueueUrl);
    List<Message> messages = sqs.receiveMessage(receiveMessageRequest).getMessages();
    for (Message message : messages) {
        System.out.println(" Message");
        System.out.println(" MessageId: " + message.getMessageId());
        System.out.println(" ReceiptHandle: " + message.getReceiptHandle());
        System.out.println(" MD5OfBody: " + message.getMD5OfBody());
        System.out.println(" Body: " + message.getBody());
        for (Entry<String, String> entry : message.getAttributes().entrySet()) {
            System.out.println(" Attribute");
            System.out.println(" Name: " + entry.getKey());
            System.out.println(" Value: " + entry.getValue());
        }
    }
    System.out.println();
}

另请注意,您可能会多次收到相同的消息.因此,允许您的工作"重新处理"相同的消息,或检测重复的消息.

Answer 2

我也面临同样的问题 - 只有一条消息被返回，然后我尝试了 receiveMessageRequest.setMaxNumberOfMessages(10) ，这将帮助我在循环中检索 10 条消息，

因为我的队列有超过 500 条记录，所以我所做的是

    List<String> messagelist = new ArrayList<>();

    try
    {
        AmazonSQS sqs = new AmazonSQSClient(credentials);
        Region usWest2 = Region.getRegion(Regions.US_WEST_2);
        sqs.setRegion(usWest2);
        boolean flag = true;

        while(flag)
        {
            ReceiveMessageRequest receiveMessageRequest = new ReceiveMessageRequest(queuename);
            receiveMessageRequest.setMaxNumberOfMessages(number_of_message_);
            receiveMessageRequest.withMaxNumberOfMessages(number_of_message_).withWaitTimeSeconds(wait_time_second_);
            List<Message> messages = sqs.receiveMessage(receiveMessageRequest).getMessages();

            for (Message message : messages) 
                  {
                    //   System.out.println("    Body:          " + message.getBody());
                       messagelist.add( message.getBody());

                       String messageReceiptHandle = message.getReceiptHandle();
                       sqs.deleteMessage(new DeleteMessageRequest().withQueueUrl(queuename).withReceiptHandle(messageReceiptHandle));
                    }
            if(messages.size()==0)
            {
                flag = false;
            }
        }         

    }
    catch (AmazonServiceException ase) {
        ase.printStackTrace();
    } catch (AmazonClientException ace) {
       ace.printStackTrace();
    }
    finally {
        return messagelist ;
    }

我正在从 SQS 读取记录，然后将其保存到一个字符串列表中，然后从队列中删除该记录。

所以最后我会把队列中的所有数据放在一个列表中