在連接表和hibernate.PropertyAccessException中映射值：無法通過反射設置器設置字段值

Question

首先發布到stackoverflow，所以如果我沒有正確發布，請原諒。 我發布了一個后續問題，其中包含舊線程上的代碼將聯結表中的映射值映射到實體，因為我無法獲得推薦的解決方案以正常運行。 我正在使用OpenXava並收到錯誤“無法執行保存操作：org.hibernate.PropertyAccessException：無法通過org.openxava.invoicing.model.CourseAssignmentId.course的反射設置器設置字段值”。 任何幫助表示贊賞。 我的代碼：

用戶類：

@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;
    }

}

課程班級：

@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;
    }


}

CourseAssignment類：

@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類：

@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

有些事要嘗試：

• 從CourseAssignmentId刪除@Embeddable注釋（我不認為它在這種情況下是合適的）
• 從CourseAssignmentId刪除@Column注釋
• 在CourseAssignmentId實現equals()和hashCode()