java - 从 JAVA API 获取 Amazon EC2 实例的公共(public) DNS

Question

我已经成功地从 JAVA API 启动、停止和检查先前创建的 EC2 实例的状态。但是，我很难获得此实例的公共(public) DNS 地址。由于我使用 StartInstancesRequest 启动实例并使用 StartInstancesResponse 获得响应，因此我无法检索实际的实例对象。下面给出了我的起始代码，它有效:

BasicAWSCredentials oAWSCredentials = new BasicAWSCredentials(sAccessKey, sSecretKey);
AmazonEC2 ec2 = new AmazonEC2Client(oAWSCredentials);
ec2.setEndpoint("https://eu-west-1.ec2.amazonaws.com");
List<String> instanceIDs = new ArrayList<String>();
instanceIDs.add("i-XXXXXXX");

StartInstancesRequest startInstancesRequest = new StartInstancesRequest(instanceIDs);
try {
        StartInstancesResult response = ec2.startInstances(startInstancesRequest);
        System.out.println("Sent! "+response.toString());
    }catch (AmazonServiceException ex){
        System.out.println(ex.toString());
        return false;
    }catch(AmazonClientException ex){
        System.out.println(ex.toString());
        return false;
    }

此外，我们将不胜感激通过 JSch 连接到此实例的任何帮助。

非常感谢!

Answer 1

这是一个可以解决问题的方法。最好在调用之前检查实例是否处于运行状态。

String getInstancePublicDnsName(String instanceId) {
    DescribeInstancesResult describeInstancesRequest = ec2.describeInstances();
    List<Reservation> reservations = describeInstancesRequest.getReservations();
    Set<Instance> allInstances = new HashSet<Instance>();
    for (Reservation reservation : reservations) {
      for (Instance instance : reservation.getInstances()) {
        if (instance.getInstanceId().equals(instanceId))
          return instance.getPublicDnsName();
      }
    }
    return null;
}