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

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; @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抱怨没有名为departmentId字段可用于建立一对一或多对关系，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; } 

您将Department中的Department字段指向DepartmentHead中的DepartmentHead字段。 Hibernate会排除要使用的ID，您不必在实际链接中指定它。

Answer 2

学生class怎么样？ 您是否在Student类中定义了ManyToOne关系。

  @Entity public class Student { @Id @GeneratedValue(strategy=GenerationType.IDENTITY) private int id; private String name; @ManyToOne private Department department; .................. 

请查看此示例 。