Java Amazon DynamoDB和类层次结构

我正在使用库处理SpringBoot和AmazonDynamodb。该类层次结构存在问题：

@DynamoDBTable(tableName = "EventLogs")
abstract class AbstractEventLogEntry implements Serializable {
  private static final long serialVersionUID = 7713867887326010287L;

  @DynamoDBHashKey(attributeName = "EventId")
  private String eventId;

  @DynamoDBAttribute(attributeName = "GeneratedAt")
  @DynamoDBMarshalling(marshallerClass = ZonedDateTimeMarshaller.class)
  private ZonedDateTime generatedAt;

  AbstractEventLogEntry() {
    eventId = new UUID().value();
    generatedAt = ZonedDateTime.now();
  }

  /* Getters / Setter */
}

…另一类：

public abstract class EventLogEntry extends AbstractEventLogEntry {
  private static final long serialVersionUID = 1638093418868197192L;

  @DynamoDBAttribute(attributeName = "UserId")
  private String userId;

  @DynamoDBAttribute(attributeName = "EventName")
  private String eventName;

  protected EventLogEntry(AdminEvent event) {
    userId = event.getUserName();
    eventName = event.getClass().getSimpleName();
  }

  protected EventLogEntry(UserEvent event) {
    userId = event.getUserId();
    eventName = event.getClass().getSimpleName();
  }

  /* Getters / Setter */
}

…另一个：

public class AdminEventLogEntry extends EventLogEntry {
  private static final long serialVersionUID = 1953428576998278984L;

  public AdminEventLogEntry(AdminEvent event) {
    super(event);
  }
}

…最后一个：

public class UserEventLogEntry extends EventLogEntry {
  private static final long serialVersionUID = 6845335344191463717L;

  public UserEventLogEntry(UserEvent event) {
    super(event);
  }
}

典型的类层次结构。现在，我正在尝试使用公共存储库存储

AdminEventLogEntry

和

UserEventLogEntry

：

@EnableScan
public interface EventLogEntryRepository extends DynamoDBCrudRepository<EventLogEntry, String> {
  // ...
}

一旦我（再次）宣布钥匙有效：

@DynamoDBHashKey(attributeName = "EventId")
private String eventId;

所以我的问题是：我是否需要重新声明层次结构之间可能通用的所有字段？它似乎无法识别来自父项的

HashKey

有什么线索吗？

我（不久前）找到了解决方案，所以我正在更新帖子，以防将来有人需要它。注意，

抽象

类已经不存在了，也许你可以出于自己的目的对它进行调整，那时我没有时间测试它（不是现在…所以它更简单，从面向对象的角度来看可能不完全正确）

问题在于类层次结构和（基于Spring的）AmazonDB客户端的配置。接下来的类是实际的解决方案

（a）Amazon DynamoDB客户端的Spring配置文件。

@EnableScan
public interface EventLogEntryRepository extends DynamoDBCrudRepository<EventLogEntry, String> { }

请注意，您可能不需要

dynamodboOperationsRef

，因为它是 仅在“每个环境”需要不同表的情况下使用。具有 DynamoDB（如果您只有一个帐户）您不能有不同的帐户 “环境”，所以你必须找到一种解决方法。这是 解决方案：为表添加前缀（并根据需要应用安全设置） 必需）

（b）DynamoDB注释的“实体”类

package io.shido.events;

// imports

@DynamoDBTable(tableName = "EventLogs")
final class EventLogEntry implements Serializable {
  // Define your own long serialVersionUID

  @DynamoDBHashKey(attributeName = "EventId")
  private String eventId;

  @DynamoDBTypeConvertedEnum
  @DynamoDBAttribute(attributeName = "EventType")
  private EventType type;

  @DynamoDBAttribute(attributeName = "EntityId")
  private String entityId;

  @Scrambled
  @DynamoDBAttribute(attributeName = "Event")
  private Event event;

  @DynamoDBAttribute(attributeName = "GeneratedAt")
  @DynamoDBTypeConverted(converter = ZonedDateTimeConverter.class)
  private ZonedDateTime generatedAt;

  public EventLogEntry() {
    generatedAt = ZonedDateTime.now();
  }

  public EventLogEntry(AdminEvent event) {
    this();
    eventId = event.getId();
    type = EventType.ADMIN;
    entityId = event.getEntityId();
    this.event = event;
  }

  public EventLogEntry(UserEvent event) {
    this();
    eventId = event.getId();
    type = EventType.USER;
    entityId = event.getEntityId();
    this.event = event;
  }

  // getters and setters (a MUST, at least till the version I'm using)

  // hashCode(), equals and toString()
}

（c）Spring存储库定义。

@EnableScan
public interface EventLogEntryRepository extends DynamoDBCrudRepository<EventLogEntry, String> { }

---

你找到解决办法了吗？找到了！到目前为止，它的工作非常棒。我会把它寄出去的。

@EnableScan
public interface EventLogEntryRepository extends DynamoDBCrudRepository<EventLogEntry, String> { }

{
  "TableName" : "local-EventLogs",
  "AttributeDefinitions" : [
    { "AttributeName" : "EventId", "AttributeType" : "S" },
    { "AttributeName" : "EventType", "AttributeType" : "S" },
    { "AttributeName" : "EntityId", "AttributeType" : "S" },
    { "AttributeName" : "Event", "AttributeType" : "S" },
    { "AttributeName" : "GeneratedAt", "AttributeType" : "S" }
  ],
  "KeySchema" : [ { "AttributeName" : "EventId", "KeyType" : "HASH" } ],
  "ProvisionedThroughput" : { "ReadCapacityUnits" : 10, "WriteCapacityUnits" : 10 }
}