@Entity
@Table(name="TEACHERS")
@SequenceGenerator(name="SEQ_TEACHERS",sequenceName="SEQ_TEACHERS")
public class Teacher {

    
    private Long id;
    
    private String code;
    
    private String name;
    
    private String type;
    
    private List<Student> students;
    
    @Id
    @GeneratedValue(generator="SEQ_TEACHERS",strategy=GenerationType.SEQUENCE)
    @Column(name="id")
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    
    @Column(name="CODE")
    public String getCode() {
        return code;
    }
    public void setCode(String code) {
        this.code = code;
    }
    
    @Column(name="NAME")
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    
    @Column(name="TYPE")
    public String getType() {
        return type;
    }
    public void setType(String type) {
        this.type = type;
    }
    
    @OneToMany(cascade=CascadeType.ALL, fetch=FetchType.EAGER)
    @JoinColumn(name="TECH_ID",nullable=true,updatable=true)
    public List<Student> getStudents() {
        return students;
    }
    public void setStudents(List<Student> students) {
        this.students = students;
    }
}

@Entity
@Table(name="STUDENTS")
@SequenceGenerator(name="SEQ_STUDENTS",sequenceName="SEQ_STUDENTS")
public class Student {

    
    private Long id;
    
    private String code;
    
    private String name;
//    @Column(name="TECH_ID")
//    private Long techId;
    
    private Teacher teacher;
    
    @Id
    @GeneratedValue(generator="SEQ_STUDENTS",strategy=GenerationType.SEQUENCE)
    @Column(name="id")
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    
    @Column(name="CODE")
    public String getCode() {
        return code;
    }
    public void setCode(String code) {
        this.code = code;
    }
    
    @Column(name="NAME")
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    
//    public Long getTechId() {
//        return techId;
//    }
//    public void setTechId(Long techId) {
//        this.techId = techId;
//    }
    
    @ManyToOne(cascade=CascadeType.ALL)
    @JoinColumn(name="TECH_ID")
    public Teacher getTeacher() {
        return teacher;
    }
    public void setTeacher(Teacher teacher) {
        this.teacher = teacher;
    }
}

public class AssociationsTest {

    /**
     * @param args
     */
    public static void main(String[] args) {
//        SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
        SessionFactory sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
        Session session = sessionFactory.openSession();
        Transaction trans = session.beginTransaction();
        Teacher t = new Teacher();
        t.setCode("000001");
        t.setName("xiaoxue");
        t.setType("shuxue");
        List<Student> list = new ArrayList<Student>();
        Student s0 = new Student();
        s0.setCode("000001");
        s0.setName("xioali");
        list.add(s0);
        Student s1 = new Student();
        s1.setCode("000002");
        s1.setName("zhangsan");
        list.add(s1);
        t.setStudents(list);
        session.save(t);
        trans.commit();

    }

}