小编Vin*_*ntS的帖子

我有一个类直接映射JSON实现Mappable(ObjectMapper框架)协议,我试图继承NSManagedObject.

class AbstractModel: NSManagedObject, Mappable {

@NSManaged var uuid: String?
@NSManaged var updatedAt: String?
@NSManaged var createdAt: String?

required init?(_ map: Map) {
    mapping(map)
}

func mapping(map: Map) {
    uuid        <- map["uuid"]
    updatedAt   <- map["updatedAt"]
    createdAt   <- map["createdAt"]

}
}

这个实现的问题是编译器抱怨mapping(map)在超级初始化器之前使用self: AbstractModel.swift:19:9: Use of 'self' in method call 'mapping' before super.init initializes self

不幸的是我以前不能调用super initializer(super.init(entity: NSEntityDescription, insertIntoManagedObjectContext: NSManagedObjectContext?))mapping(map)因为我需要self得到它NSManagedObjectContext.

我该怎么解决这个问题？

我尝试在 Spring Boot 应用程序中使用 AmazonSNS，并且可以在本地使用它，但是当我将其部署到开发服务器上时，我收到此错误：

Caused by: com.amazonaws.SdkClientException: Unable to load AWS credentials from any provider in the chain: [com.amazonaws.auth.EC2ContainerCredentialsProviderWrapper@46a123e4: The requested metadata is not found at http://169.254.169.254/latest/meta-data/iam/security-credentials/ , com.amazonaws.auth.profile.ProfileCredentialsProvider@44bc2449: profile file cannot be null]

如果我没有弄错的话，我的服务器将无法获取任何 AWS 凭证。我不明白为什么，因为 AWS_ACCESS_KEY_ID 和 AWS_SECRET_ACCESS_KEY 设置为环境变量。我的代码看起来像这样：

private AmazonSNS amazonSNS;

@Autowired
public AmazonSNSPublisherService() {
    this.amazonSNS = AmazonSNSClientBuilder.standard().withCredentials(DefaultAWSCredentialsProviderChain.getInstance()).withRegion("eu-west-1").build();
}

我试过这个：

this.amazonSNS = AmazonSNSClientBuilder.standard().withRegion("eu-west-1").build();

和这个：

this.amazonSNS = AmazonSNSClientBuilder.standard().withCredentials(new EnvironmentVariableCredentialsProvider()).withRegion("eu-west-1").build();

但我总是遇到同样的错误。