无法从以下位置获取标识符

Question

尝试将实体保存到数据库时遇到以下问题MongoDB。

我在用Spring CrudRepository

我的代码如下所示：

UserDocument user = processUser();
userRepository.save(user);

这是我收到的错误：

java.lang.IllegalStateException: Could not obtain identifier from UserDocument(id=null, ownerId=..., ...)!
    at o.s.d.m.TargetAwareIdentifierAccessor.getRequiredIdentifier(TargetAwareIdentifierAccessor.java:47)
    at o.s.d.m.c.EntityOperations$MappedEntity.getId(EntityOperations.java:466)
    ... 53 frames excluded

用户文档类：

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.NoArgsConstructor;
import lombok.experimental.Accessors;
import lombok.experimental.SuperBuilder;
import org.bson.types.ObjectId;
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.index.CompoundIndex;
import org.springframework.data.mongodb.core.index.CompoundIndexes;
import org.springframework.data.mongodb.core.mapping.Document;

@Data
@EqualsAndHashCode(callSuper = true)
@NoArgsConstructor
@AllArgsConstructor
@Accessors(chain = true)
@SuperBuilder
@Document(collection = UserDocument.COLLECTION)
public class UserDocument extends BaseDocument<ObjectId> {

  public static final String COLLECTION = "users";

  @Id
  private ObjectId id;

 .....
}

Answer 1

对于任何正在解决这个问题的人 - 就我而言，这是一个问题，mapstruct Mapper因为副作用是填充超类中的字段：

import org.springframework.data.annotation.CreatedDate;
import org.springframework.data.annotation.LastModifiedDate;
import org.springframework.data.annotation.Version;

@Data
@NoArgsConstructor(access = AccessLevel.PROTECTED)
@AllArgsConstructor(access = AccessLevel.PROTECTED)
@Accessors(chain = true)
@SuperBuilder
public abstract class BaseDocument<ID extends Serializable> implements Persistable<ID> {

  @Version
  private Long revision;

  @CreatedDate
  private Instant createdDateTime;

  @LastModifiedDate
  private Instant lastModifiedDateTime;

  @Override
  public boolean isNew() {
    return isNull(createdDateTime);
  }
}

null因此，在保存新实体时请确保这些字段是正确的！

Answer 2

我也为此苦苦挣扎。就我而言，问题是@Version我尝试保存的对象中的字段设置为 0。将其设置为 null 后，我就不再有这个字段了。我注意到跟踪 getQueryForVersion、doSaveVersioned 中的方法...

java.lang.IllegalStateException: Could not obtain identifier from .....
    at org.springframework.data.mapping.TargetAwareIdentifierAccessor.getRequiredIdentifier(TargetAwareIdentifierAccessor.java:48)
    at org.springframework.data.mongodb.core.EntityOperations$MappedEntity.getId(EntityOperations.java:527)
    at org.springframework.data.mongodb.core.EntityOperations$MappedEntity.getQueryForVersion(EntityOperations.java:556)
    at org.springframework.data.mongodb.core.MongoTemplate.doSaveVersioned(MongoTemplate.java:1383)
    at org.springframework.data.mongodb.core.MongoTemplate.save(MongoTemplate.java:1370)
    at org.springframework.data.mongodb.repository.support.SimpleMongoRepository.save(SimpleMongoRepository.java:88)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:564)