JPA异常：org.hibernate.MappingException：无法确定

Question

我已经在用户和items表之间创建了一对多关系。下面是SQL和Java代码。我得到了由以下原因引起的异常：

org.hibernate.mappingexception`:无法确定表：items中：com.model.users的类型，无法确定列:[org.hibernate.mapping.column（users）]的类型

    CREATE TABLE users
    ( id integer NOT NULL DEFAULT nextval('userseq'::regclass),
      email character varying(64) NOT NULL,
      passwords character varying(64) NOT NULL
      CONSTRAINT users_pkey PRIMARY KEY (id)
    )
  
    CREATE TABLE items
    ( id integer NOT NULL DEFAULT nextval('itemseq'::regclass),
      userid integer NOT NULL,
      itemname character varying(4096) NOT NULL,
      CONSTRAINT message_pkey PRIMARY KEY (id),
      CONSTRAINT userid_fkey FOREIGN KEY (userid)
      REFERENCES users (id) MATCH SIMPLE
      ON UPDATE NO ACTION ON DELETE NO ACTION
     )

       public class Users  {
        private Items items;
            
            @OneToMany(targetEntity=Items.class, mappedBy="users", fetch=FetchType.LAZY)  //sender is message(c)filed
            public List<Items> getItems() {
                return items;
            }
        }
        
        @ManyToOne(fetch = FetchType.LAZY, targetEntity = Users.class)
            @JoinColumn(name = "userid", nullable = false)            // sendid is database column
            public Users getUsers() {
                return users;
            }

原因：javax.persistence.persistenceException:[persistenceUnit:default]无法构建HibernateSessionFactory；嵌套异常是org.hibernate.mappingException：无法确定表：items中：com.model.users的类型，无法确定列:[org.hibernate.mapping.column（users）]的类型

原因：org.hibernate.mappingException：无法确定表：users中列:[org.hibernate.mapping.column（items）]的类型：java.util.list

Answer 1

Users类不应该有一个项目列表吗？尝试以下方法，

@Entity
@Table(name = "users")
public class Users{

    @OneToMany(mappedBy = "user")
    private List<Items> items;

}

@Entity
@Table(name = "items")
public class Items{

    @JoinColumn(name="userid")
    @ManyToOne
    private User user;

}