发送通知到主题SNS AWS |春季靴

Question

我正在尝试使用spring boot和spring-cloud-aws-messaging将通知消息发送到aws中的SNS-Topic。 我的AWS配置如下-：

@Bean
public AmazonSNS amazonSNS(){
    if(Objects.nonNull(snsClient)){
        final AWSCredentials awsCredentials = new BasicAWSCredentials(awsConfig.getAccessKey(),
                awsConfig.getSecretKey());
        snsClient = AmazonSNSClientBuilder.standard()
                .withRegion(awsConfig.getRegion())
                .withCredentials(new AWSStaticCredentialsProvider(awsCredentials))
                .build();
    }
    return snsClient;
}

@Bean
public NotificationMessagingTemplate notificationMessagingTemplate(){
    return new NotificationMessagingTemplate(amazonSNS());
}

我的休息控制器代码如下

 @Autowired
NotificationMessagingTemplate messagingTemplate;


@GetMapping("/postMessage")
public void sendMessage(){
    System.out.println("Sending Message");
    messagingTemplate.sendNotification("example-topic-arn", "Test Message","Test Subject");
}

我收到此例外-：

[Request processing failed; nested exception is org.springframework.messaging.MessageDeliveryException: Failed to send message to TopicMessageChannel[TopicMessageChannel@2a7a4044]; nested exception is java.lang.NullPointerException, failedMessage=GenericMessage [payload=Test Message, headers={NOTIFICATION_SUBJECT_HEADER=Test Message, id=96817d20-fb5d-7e07-76e2-e3492986df0b, contentType=text/plain;charset=UTF-8, timestamp=1573384357842}]] with root cause

我是aws的新手，请帮忙。