java - 如何从SQS消息中获取 `ApproximateReceiveCount`

Question

我正在使用 Amazon SQS。我的目标是使用 Java SDK(v2.10.4、Java 11)从 ReceiveMessage API action 读取 ApproximateReceiveCount 属性。

我尝试了以下代码，但 message.attributes() 不包含所需的 key :

String getApproximateReceiveCount() {
    var receiveMessageRequest = ReceiveMessageRequest.builder()
        .queueUrl("https://sqs.eu-west-1.amazonaws.com/012345678910/my-example-queue")
        .build();
    var sqsClient = SqsClient.builder().endpointOverride(URI.create("http://localhost:4576")).build();
    var response = sqsClient.receiveMessage(receiveMessageRequest);
    var message = response.messages().get(0);
    return message.attributes().get(MessageSystemAttributeName.APPROXIMATE_RECEIVE_COUNT);
}

如何在此映射中接收 MessageSystemAttributeName.APPROXIMATE_RECEIVE_COUNT 键的条目？

Answer 1

根据您链接的 ReceiveMessage 的 the documentation page，有一个名为 AttributeName.N 的参数，描述为

A list of attributes that need to be returned along with each message. These attributes include:

• [...]
• ApproximateReceiveCount – Returns the number of times a message has been received from the queue but not deleted.

因此，您需要在请求中请求该属性，以便它在响应中可用。为此，请使用 ReceiveMessageRequestBuilder.attributeNamesWithStrings() 方法，如下所示:

String getApproximateReceiveCount() {
    var receiveMessageRequest = ReceiveMessageRequest.builder()
        .queueUrl("https://sqs.eu-west-1.amazonaws.com/012345678910/my-example-queue")
        .attributeNamesWithStrings(MessageSystemAttributeName.APPROXIMATE_RECEIVE_COUNT.toString())
        .build();
    var sqsClient = SqsClient.builder().endpointOverride(URI.create("http://localhost:4576")).build();
    var response = sqsClient.receiveMessage(receiveMessageRequest);
    var message = response.messages().get(0);
    return message.attributes().get(MessageSystemAttributeName.APPROXIMATE_RECEIVE_COUNT);
}

请注意，有两个名称相似的方法，您不能使用它们:

• .attributeNames() - 参数枚举未列出所需的键，
• .messageAttributeNames() - 对应于与消息正文一起发送的属性。