在spring-data-mongodb中检索map mongo集合

Question

我正在使用spring-data-mongo来检索我的notifications集合中的这些对象：

_id:ObjectId("123123123123")
1510067387875:Object
    date:"1510067387875"
    title:"Sample title"
    text:"Sample Text"
_id:ObjectId("123223123123")
1110067387875:Object
    date:"1110067387875"
    title:"Sample title"
    text:"Sample Text"

因此，我定义了我的存储库类: NotificationRepository

@Repository
@Transactional("mongoTransactionManager")
@PersistenceContext(name = "mongodbEntityManager")
public interface NotificationRepository extends MongoRepository<NotificationMap, ObjectId> {
}

和NotificationMap：

@Document(collection = "notifications")
public class NotificationMap {

@Id
private ObjectId _id;

private Map<String, Notification> map;

/**
 * @return the map
 */
public Map<String, Notification> getMap() {
    return map;
}

/**
 * @param map the map to set
 */
public void setMap(Map<String, Notification> map) {
    this.map = map;
}

public ObjectId get_id() {
    return _id;
}

/**
 * @param _id the _id to set
 */
public void set_id(ObjectId _id) {
    this._id = _id;
}

}

最后是Notification类：

public class Notification {
    private long date;
    private String title;
    private String text;
    private String dateString;

但返回的是空对象。我应该如何访问这些信息

Answer 1

NotificationMap似乎是不必要的。只需使用：

public interface NotificationRepository
  extends MongoRepository<Notification, ObjectId> {