java - 使用条件和限制进行查询时， hibernate 异常 'could not resolve property'

我在 hibernate 中定义了一个OneToMany关系，如下所示:

@Entity
@Table(name = "groups")
public class Group extends BaseModel {// BaseModel defines id as @Id and @GeneratedValue

    @OneToMany
    @JoinColumn(name = "group_id")
    private List<User> users;

    // other fields, getters and setters omitted
}


@Entity
@Table(name = "users")
public class User extends BaseModel {

    @ManyToOne
    @JoinColumn(name = "group_id")
    private Group group;

    // other fields, getters and setters omitted
}

列group_id在users表中。
调用方法Group.getUsers()和User.getGroup()可以正常工作。但是我还需要在group_id列之后进行查询:

Criteria criteria = Activator.getDefault().getSQLSession().createCriteria(User.class);
Criterion c = Restrictions.eq("group_id", 1); // an id of a group
criteria.add(c);

Criterion对象是在一个方法中创建的，它可以用于其他一对多表或可以包含其他列，因此我不能使用getUsers()方法。

不幸的是，上面的代码给出了以下异常:

org.hibernate.QueryException: could not resolve property: group_id of: com.example.User
    at org.hibernate.persister.entity.AbstractPropertyMapping.propertyException(AbstractPropertyMapping.java:81)
    at org.hibernate.persister.entity.AbstractPropertyMapping.toType(AbstractPropertyMapping.java:75)
    at org.hibernate.persister.entity.AbstractEntityPersister.getSubclassPropertyTableNumber(AbstractEntityPersister.java:1482)
    at org.hibernate.persister.entity.BasicEntityPropertyMapping.toColumns(BasicEntityPropertyMapping.java:62)
    and so on ...

可能是什么问题呢？

编辑:

在user759837建议的更改(Criterion c = Restrictions.eq("group", 1);)之后，当我调用criteria.list()时，出现以下错误消息:could not get a field value by reflection getter of com.example.Group.id

java.lang.IllegalArgumentException: Can not set java.lang.Long field com.example.BaseModel.id to java.lang.Long
    at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source)
    at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source)
    at sun.reflect.UnsafeFieldAccessorImpl.ensureObj(Unknown Source)
    at sun.reflect.UnsafeObjectFieldAccessorImpl.get(Unknown Source)
    at java.lang.reflect.Field.get(Unknown Source)
    at org.hibernate.property.DirectPropertyAccessor$DirectGetter.get(DirectPropertyAccessor.java:59)
    at org.hibernate.tuple.entity.AbstractEntityTuplizer.getIdentifier(AbstractEntityTuplizer.java:227)
    at org.hibernate.persister.entity.AbstractEntityPersister.getIdentifier(AbstractEntityPersister.java:3875)
    at org.hibernate.persister.entity.AbstractEntityPersister.isTransient(AbstractEntityPersister.java:3583)
    at org.hibernate.engine.ForeignKeys.isTransient(ForeignKeys.java:203)
    at org.hibernate.engine.ForeignKeys.getEntityIdentifierIfNotUnsaved(ForeignKeys.java:242)
    at org.hibernate.type.EntityType.getIdentifier(EntityType.java:456)
    at org.hibernate.type.ManyToOneType.nullSafeSet(ManyToOneType.java:130)
    ...

BaseModel类是

@MappedSuperclass
public abstract class BaseModel {

    @Id
    @GeneratedValue
    private Long id;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }
}

我也尝试过long id，但这是相同的错误。

编辑2:

经过大量挖掘后，看来Criterion对象应该接收一个组对象作为参数，而不是id:Restrictions.eq("group", {A_GROUP_OBJECT});
我可以在那里发送一个ID吗？

最佳答案

您的列是 group_id ，您应该使用属性 group
...
条件c = Restrictions.eq(“ group ”，1);//群组的ID
...