java.lang.ClassCastException:java.lang.String不能强制转换为java.lan

Question

我在尝试将实体"UserAccount"持久化到数据库表中时遇到此错误。

@Entity
@Table(name = "user_account")
public class UserAccount extends BaseEntity {
@OneToMany(cascade = CascadeType.ALL)
@JoinColumn(name = "useraccount_id")
@MapKeyEnumerated(EnumType.STRING)
private Map<PhoneType, PhoneNumber> phones = new HashMap<PhoneType, PhoneNumber>();
//... other attributes
//... default constructor, getters and setters
}

public enum PhoneType {
HOME("home"),
MOBILE("mobile"),
FAX("fax"),
WORK("work");
private String value;
PhoneType(String value) {
this.value = value;
}
@JsonValue
public String getValue() {
return value;
}
}

@Entity
@Table(name = "phone_number")
public class PhoneNumber extends BaseEntity {
private String areaCode;
private String number;
//... default constructor, getters and setters
}

最后。。

public class UserAccountRepository {
@Inject
EntityManager entityManager;
@Override
public UserAccount save(UserAccount userAccount) {
if (userAccount.getId() == null) {
entityManager.persist(userAccount);
} else {
userAccount = entityManager.merge(userAccount);
}
return userAccount;
}
//.. other methods
}

Caused by: java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Enum
at org.eclipse.persistence.mappings.converters.EnumTypeConverter.convertObjectValueToDataValue(EnumTypeConverter.java:165)
at org.eclipse.persistence.mappings.foundation.AbstractDirectMapping.extractIdentityFieldsForQuery(AbstractDirectMapping.java:568)
at org.eclipse.persistence.internal.queries.MappedKeyMapContainerPolicy.getKeyMappingDataForWriteQuery(MappedKeyMapContainerPolicy.java:145)
at org.eclipse.persistence.mappings.OneToManyMapping.updateTargetRowPostInsertSource(OneToManyMapping.java:1425)
at org.eclipse.persistence.mappings.OneToManyMapping.performDataModificationEvent(OneToManyMapping.java:936)
at org.eclipse.persistence.internal.sessions.CommitManager.commitAllObjectsWithChangeSet(CommitManager.java:162)
at org.eclipse.persistence.internal.sessions.AbstractSession.writeAllObjectsWithChangeSet(AbstractSession.java:4387)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabase(UnitOfWorkImpl.java:1493)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabaseWithChangeSet(UnitOfWorkImpl.java:1583)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.issueSQLbeforeCompletion(UnitOfWorkImpl.java:3258)
at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.issueSQLbeforeCompletion(RepeatableWriteUnitOfWork.java:357)
at org.eclipse.persistence.transaction.AbstractSynchronizationListener.beforeCompletion(AbstractSynchronizationListener.java:160)
at org.eclipse.persistence.transaction.JTASynchronizationListener.beforeCompletion(JTASynchronizationListener.java:70)
at com.sun.enterprise.transaction.JavaEETransactionImpl.commit(JavaEETransactionImpl.java:452)
... 94 more

其他有相同错误的问题建议在Enum类型的属性上添加@Enumerated(EnumType.STRING(，我在phonesMap上使用了@MapKeyEnumerated(EnumType.STRING)，但我仍然看到收到这个错误。有什么线索表明我错在哪里了吗？

请告诉我，如果我没有按照SO的指导提出问题，我会纠正(因为这是我的第一个问题(。

Answer 1

我对PhoneNumber类进行了如下所示的更改

@Entity
@Table(name = "phone_number")
public class PhoneNumber extends BaseEntity {
private PhoneType type;
private String areaCode;
private String number;
//... default constructor, getters and setters
}

然后在CCD_ 4中添加CCD_。

@OneToMany(cascade = CascadeType.ALL)
@JoinColumn(name = "useraccount_id")
@MapKeyEnumerated(EnumType.STRING)
@MapKey(name = "type")
private Map<PhoneType, PhoneNumber> phones = new HashMap<PhoneType, PhoneNumber>();

通过这些更改，我现在可以成功地将UserAccount对象保存到数据库表中。