Json在spring集成中不转换为对象

Question

我要

.transform(Transformers.fromJson(SNSMessage.class))

不返回从我的JSON转换的值。JSON输入是

{
    "Type": "Notification",
    "MessageId": "b5c64f3f-59e3-5fce-9ad6-1e98973c9537",
    "TopicArn": "arn:aws:sns:us-east-1:194477963434:local-hera-update",
    "Subject": "com.accuity.hera.model.HeraNotification",
    "Message": "{\"id\":\"65e60559-cab5-4027-88a2-46185fbd50b9\",\"resourceType\":\"listItem\",\"action\":\"I\",\"timeOfAction\":\"2017-05-30T19:48:46Z\",\"source\":\"gwl\"}",
    "Timestamp": "2017-05-30T19:48:47.593Z",
    "SignatureVersion": "1",
    "Signature": "Xz0qg0byLMA1fwIRbi7aWcEzhtcLBOmzyUluL1W5URu4WaiEO3G\/+hPSpsFXGxcSYNYRgpKhL9QAP2qLkuMlSEMqiEOHaSr88UaB8QRV2lUEjdBAWpuFYVBPdb+jpo6n3m89vVHoYfFWk8yBkc0zuoRl4OYcUXfTZiWWQkkrT8r9OzWU8LxQwgf0jgr1xEoqbl7uMHIp7nHp3cKstQ0mbK6yxMQ8faxfDm+IwH3k8BBH2\/CXmRg9WME6JK77jvagMUHNhUahWKIjm4iz+TCQCdnmHQR21hmgxlkhdrSxZ1FBbk6BjxfX7gorEwwfY1gYNoZCXxsN63+4vSiFMlOAAQ==",
    "SigningCertURL": "https:\/\/sns.us-east-1.amazonaws.com\/SimpleNotificationService-b95095beb82e8f6a046b3aafc7f4149a.pem",
    "UnsubscribeURL": "https:\/\/sns.us-east-1.amazonaws.com\/?Action=Unsubscribe&SubscriptionArn=arn:aws:sns:us-east-1:194477963434:local-hera-update:7de3da56-9e6c-43ca-9abc-d46fff379380"
}

类的定义是：

public class SNSMessage {
    private String Type;
    private String MessageId;
    private String TopicArn;
    private String Subject;
    private String Message;
    private String Timestamp;
    private String SignatureVersion;
    private String Signature;
    private String SigningCertURL;
    private String UnsubscribeURL;
}

知道为什么SNSMessage将其所有字段设置为null回来吗？

Answer 1

您面临的问题是您的json属性使用的大写化与pojo属性不同。

这意味着您将Type作为json属性，并为您的getter检测到type。

您需要像这样使用@JsonProperty注释：

@JsonProperty("Type") 
private String type;
...
// getters / setters for type

顺便说一句，如果您不想遵循java命名标准，并且拥有Type和pojo属性，那么只需将@JsonProperty添加到没有args的属性中即可。