Question

我一直在尝试在Java中实现一个GetAttributeRequest，它具有与以下C＃代码类似的功能。

try
{
  long epochWindowTime = ToEpochTimeInMilliseconds(DateTime.UtcNow.Subtract(this.SQSWindow));
  int numberOfMessages = 0;

   // 1st query to determine the # of Messages available in the queue
   using (AmazonSQSClient client = new AmazonSQSClient(
           this.AWSAccessKey, this.AWSSecretAccessKey,
           ew AmazonSQSConfig() { ServiceURL = this.AWSSQSServiceUrl }))
  {
  // get the NumberOfMessages to optimize how to Receive all of the messages from the queue
     GetQueueAttributesRequest attributesRequest = new GetQueueAttributesRequest();
     attributesRequest.QueueUrl = this.QueueUrl;
     attributesRequest.AttributeName.Add("ApproximateNumberOfMessages");
     numberOfMessages = client.GetQueueAttributes(attributesRequest).GetQueueAttributesResult.ApproximateNumberOfMessages;
  }

我对Java实现的尝试如下所示，

try
{
    long epochWindowTime;
    int numberOfMessages = 0;
    Map<String, String> attributes;

    // Setup the SQS client
    AmazonSQS client = new AmazonSQSClient(new 
            ClasspathPropertiesFileCredentialsProvider());

    client.setEndpoint(this.AWSSQSServiceUrl);

    // get the NumberOfMessages to optimize how to 
    // Receive all of the messages from the queue

    GetQueueAttributesRequest attributesRequest = 
            new GetQueueAttributesRequest();
    attributesRequest.setQueueUrl(this.QueueUrl);
    //attributesRequest.setAttributeNames();
    attributes = client.getQueueAttributes(attributesRequest).
            getAttributes();

    numberOfMessages = Integer.valueOf(attributes.get(
            "ApproximateNumberOfMessages")).intValue();

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

}

因为添加属性名称的Java AmazonSQS实现需要作为Collection我不明白我将如何正确添加“ApproximateNumberOfMessages”。

我也很好奇是否有更好的替代

new AmazonSQSClient(new ClasspathPropertiesFileCredentialsProvider());

更接近C＃实现？原因是此方法旨在用作SDK的一部分，AWSAccessKey和AWSSecretAccessKey将作为单独配置文件的一部分。我是创建自己的AWSCredentialsProvider的唯一选择吗？

Answer 1

withAttributeNames接受vararg属性列表。

String attr = "ApproximateNumberOfMessages";
Map<String, String> attributes = client.getQueueAttributes(new GetQueueAttributesRequest(this.QueueUrl).withAttributeNames(attr)).getAttributes();
int count = Integer.parseInt(attributes.get(attr));

Java SDK有多种构造凭据的方法。如果您可以随时使用密钥，则使用BasicAWSCredentials是最快的。

AmazonSQS client = new AmazonSQSClient(new BasicAWSCredentials("accessKey", "secretKey"));

在Java中创建GetAttributeRequest

1 个答案: