学生-课程-成绩表设计

学生：

@Entity
public class Student {
    private int id;
    private String name;
    private Set<Course> courses = new HashSet<Course>();
    @Id
    @GeneratedValue
    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="score",//与Score中设置一致
            joinColumns=@JoinColumn(name="student_id"),
            inverseJoinColumns=@JoinColumn(name="course_id")
            )
    public Set<Course> getCourses() {
        return courses;
    }
    public void setCourses(Set<Course> courses) {
        this.courses = courses;
    }
}

课程：

@Entity
public class Course {
    private int id;
    private String name;
    @Id
    @GeneratedValue
    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;
    }
}

成绩：

@Entity
@Table(name="score")
public class Score {
    private int id;
    private int score;
    private Student student;
    private Course course;
    
    @Id
    @GeneratedValue
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    @ManyToOne
    @JoinColumn(name="student_id")
    public Student getStudent() {
        return student;
    }
    public void setStudent(Student student) {
        this.student = student;
    }
    @ManyToOne
    @JoinColumn(name="course_id")
    public Course getCourse() {
        return course;
    }
    public void setCourse(Course course) {
        this.course = course;
    }
    public int getScore() {
        return score;
    }    
    public void setScore(int score) {
        this.score = score;
    }    
}

junit:

public class TestTree {
    private static SessionFactory sf;
    @Before
    public void beforeTest(){
        sf = new Configuration().configure().buildSessionFactory();
    }
    @After
    public void afterTest(){
        sf.close();
    }
    
    @Test
    public void testSave(){
        Student s = new Student();
        s.setName("张三");
        Course yuwen = new Course();
        yuwen.setName("语文");
        Score score = new Score();
        score.setCourse(yuwen);
        score.setStudent(s);
        score.setScore(90);
        
        Session sess = sf.getCurrentSession();
        sess.beginTransaction();
        
        sess.save(s);
        sess.save(yuwen);
        sess.save(score);
        sess.getTransaction().commit();

    }
    
    @Test
    public void testLoad(){
        Session sess = sf.getCurrentSession();
        sess.beginTransaction();
        Student s = (Student)sess.load(Student.class, 2);
        for(Course c : s.getCourses()){
            System.out.println(c.getName());
        }
        sess.getTransaction().commit();

    }
}