AnnotationException引用的属性不是(一个|多个)ToOne

Question

我试图建立一对一的关系.但我得到错误:

AnnotationException Referenced property not a (One|Many)ToOne
on
com.student.information.service.Department.departmentId in mappedBy of com.student.information.service.DepartmentHead.department

两个实体几乎完全相同.部门可以存在部门负责人.

Department.Java

@Entity
@Table(name="department", catalog="student")
public class Department {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Integer departmentId;

    @Column(name="dept_name")
    private String departmentName;

    @OneToMany(mappedBy="department",cascade = CascadeType.ALL)
    private List<Student> student; 

    @OneToOne(targetEntity=Department.class)
    private DepartmentHead departmenthead;
}       

DepartmentHead.java

@Entity
@Table(name="departmenthead", catalog = "student")
public class DepartmentHead {

    //This is mapped with the department id

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private int id;

    @Column(name="headname")
    private String headName;

    @OneToOne(mappedBy = "departmentId",fetch = FetchType.LAZY,cascade=CascadeType.ALL)
    @JoinColumn(name="dept_id")
    private Department department;  
}

引起:org.hibernate.AnnotationException:引用的属性不是(一个|多个)ToOne:

有人可以指出我正确的方向,我正在犯的错误.我在过去的两天里一直在努力,而且无法找到问题的解决方案.在此先感谢您的帮助.

Answer 1

您错误地设置了映射.Hibernate抱怨没有调用的字段departmentId可用于建立一对一或多个关系,这是正确的.

您想要像这样映射您的值.

Department.Java

@Entity
@Table(name="department", catalog="student")
public class Department {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Integer departmentId;

    @OneToOne
    @JoinColumn(name = "id")
    private DepartmentHead departmenthead;
}       

DepartmentHead.java

@Entity
@Table(name="departmenthead", catalog = "student")
public class DepartmentHead {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private int id;

    @OneToOne(mappedBy = "departmenthead")
    private Department department;  
}

你点Department场DepartmentHead的DepartmentHead内场Department.Hibernate会排除要使用的ID,您不必在实际链接中指定它.