Hibernate annotation ManyToMany的中间表加入自己的字段存储报错

[lg_asus]

Student单向ManyToMany Course, 中间表是Score, 其中Score单向ManyToMany Student和Course,Score中用studentId和courseId作为联合主键，同时还有自己的字段score成绩（nullable=true）。在保存时：new 一个Student、Course、Score， 设置好关系后，Score.setScore(90) 设置成绩分数，结果执行两次insert into score,duplicate entry for primary key.

@Entity
@Table(name="t_student")
public class Student {

	private int id;
	private String name;
	private Set<Course> courses = new HashSet<Course>();
	@Id
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	@ManyToMany
	@JoinTable(name="t_score",joinColumns={@JoinColumn(name="studentId")},inverseJoinColumns={@JoinColumn(name="courseId")})
	public Set<Course> getCourses() {
		return courses;
	}
	public void setCourses(Set<Course> courses) {
		this.courses = courses;
	}
	
}

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

	private int id;
	private String name;
	@Id
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
}


@Entity
@Table(name="t_score")
@IdClass(ScorePK.class)
public class Score {
	private int score;
	private Student student;
	private Course course;
	@Column(nullable=true)
	public int getScore() {
		return score;
	}
	public void setScore(int score) {
		this.score = score;
	}
	@Id
	@ManyToOne
	@JoinColumn(name="studentId")
	public Student getStudent() {
		return student;
	}
	public void setStudent(Student student) {
		this.student = student;
	}
	@Id
	@ManyToOne
	@JoinColumn(name="courseId")
	public Course getCourse() {
		return course;
	}
	public void setCourse(Course course) {
		this.course = course;
	}
	
}


@Entity
public class ScorePK implements java.io.Serializable{
	private Student student;
	private Course course;
	public Student getStudent() {
		return student;
	}
	public void setStudent(Student student) {
		this.student = student;
	}
	public Course getCourse() {
		return course;
	}
	public void setCourse(Course course) {
		this.course = course;
	}
	
	@Override
	public boolean equals(Object o){
		if(o instanceof ScorePK){
			ScorePK t = (ScorePK) o;
			return t.getStudent() == this.getStudent()
				&& t.getCourse()==this.getCourse();
		}
		return false;
	}
	
	@Override
	public int hashCode(){
		return this.student.hashCode();
	}
}

[lg_asus]

session.beginTransaction();
		Course c = new Course();
		c.setId(21);
		c.setName("English");
		
		Student s = new Student();
		s.setId(11);
		s.setName("Hiway");
		s.getCourses().add(c);
		
		Score sc = new Score();
		sc.setScore(90);
		sc.setStudent(s);
		sc.setCourse(c);
		
		session.save(c);
		session.save(s);
		session.save(sc);
		
		session.getTransaction().commit();

显示的sql中：
执行两次insert into t_score
Hibernate:
insert
into
t_score
(score, courseId, studentId)
values
(?, ?, ?)
Hibernate:
insert
into
t_score
(studentId, courseId)
values
(?, ?)
显然是有问题的。
如果session.save(sc) 注释掉的话，则只执行一次insert into score，但那个分数没插进去。

请问如何解决？

[lg_asus]

session.beginTransaction();
		Course c = new Course();
		c.setId(21);
		c.setName("English");
		
		Student s = new Student();
		s.setId(11);
		s.setName("Hiway");
		s.getCourses().add(c);
		
		Score sc = new Score();
		sc.setScore(90);
		sc.setStudent(s);
		sc.setCourse(c);
		
		session.save(c);
		session.save(s);
		session.save(sc);
		
		session.getTransaction().commit();

这是测试代码

[lg_asus]

session.beginTransaction();
		Course c = new Course();
		c.setId(21);
		c.setName("English");
		
		Student s = new Student();
		s.setId(11);
		s.setName("Hiway");
		s.getCourses().add(c);
		
		Score sc = new Score();
		sc.setScore(90);
		sc.setStudent(s);
		sc.setCourse(c);
		
		session.save(c);
		session.save(s);
		session.save(sc);
		
		session.getTransaction().commit();

[xuehaiwuyaya]

我也遇到了相同的问题，求解决啊

[xuehaiwuyaya]

还是没人解决？再顶