java - 连接表和 hibernate.PropertyAccessException : could not set a field value by reflection setter 中的映射值

Question

第一次发帖到stackoverflow，所以如果我发帖不正确，请原谅。我在旧线程上发布了一个带有代码的后续问题 Mapping value in junction table to Entity因为我无法获得推荐的解决方案以正常运行。我正在使用 OpenXava 并收到错误“无法执行保存操作:org.hibernate.PropertyAccessException:无法通过 org.openxava.invoicing.model.CourseAssignmentId.course 的反射 setter 设置字段值”。任何帮助表示赞赏。我的代码:

用户类别:

@Entity
@Table(name="users")
public class User {
    @Id
    @Column(name="pk1")
    private Long id;

    public Long getid() {
        return id;
    }

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

    @Column(name="user_id")
    private String userID;

    public String getuserID(){
        return userID;
    }

    public void setuserID(String userID) {
        this.userID = userID;
    }

    @OneToMany(mappedBy="user")
    private Collection<CourseAssignment> courseAssignments;

    public Collection<CourseAssignment> getcourseAssignments() {
        return courseAssignments;
    }

    public void setcourseAssignments(Collection<CourseAssignment> courseAssignments) {
        this.courseAssignments = courseAssignments;
    }

}

类(class)类别:

@Entity
@Table(name="courses")
public class Course {

    @Id
    @Column(name="pk1")
    private Long id;

    public Long getid() {
        return id;
    }

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

    @Column(name="course_name")
    private String name;

    public String getname() {
        return name;
    }

    public void setname(String name) {
        this.name = name;
    }   

    @OneToMany(mappedBy = "course")
    private Collection<CourseAssignment> courseAssignments;

    public Collection<CourseAssignment> getcourseAssignments() {
        return courseAssignments;
    }

    public void setcourseAssignments(Collection<CourseAssignment> courseAssignments) {
        this.courseAssignments = courseAssignments;
    }


}

类(class)作业类:

@Entity
@Table(name="course_users")
@IdClass(CourseAssignmentId.class)
public class CourseAssignment {

    @Id
    @ManyToOne
    @JoinColumn(name="user_pk1")
    private User user;

    public User getuser() {
        return user;
    }

    public void setuser(User user) {
        this.user = user;
    }

    @Id
    @ManyToOne
    @JoinColumn(name="crsmain_pk1")
    private Course course;

    public Course getcourse() {
        return course;
    }

    public void setcourse(Course course) {
        this.course = course;
    }

    @Column(name="role")
    private String role;

    public String getrole() {
        return role;
    }

    public void setrole(String role) {
        this.role = role;
    }
}

CourseAssignmentId 类:

@Embeddable
public class CourseAssignmentId implements java.io.Serializable {

    private static final long serialVersionUID = 1L;


    @Column(name="user_pk1")
    private Long user;

    public Long getuser() {
        return user;
    }

    public void setuser(Long user) {
        this.user = user;
    }

    @Column(name="crsmain_pk1")
    private Long course;

    public Long getcourse() {
        return course;
    }

    public void setcourse(Long course) {
        this.course = course;
    }   
}

Answer 1

一些尝试:

• 从 CourseAssignmentId 中删除 @Embeddable 注释(我认为在这种情况下不合适)
• 从 CourseAssignmentId 中删除 @Column 注释
• 在 CourseAssignmentId 中实现 equals() 和 hashCode()