Hibernate级联关系OneToMany之 Annotation实现

[java] view
plaincopy

1. package com.lwp.hibernate.Model;
2. import java.io.Serializable;
3. import javax.persistence.CascadeType;
4. import javax.persistence.Column;
5. import javax.persistence.Entity;
6. import javax.persistence.FetchType;
7. import javax.persistence.GeneratedValue;
8. import javax.persistence.Id;
9. import javax.persistence.JoinColumn;
10. import javax.persistence.ManyToOne;
11. import javax.persistence.Table;
12. @Entity
13. @Table(name="ORDERS")
14. public class Order implements Serializable{
15. private static final long serialVersionUID = 1L;
16. public Order(){}
17. public Order(String orderNumber){
18. this.orderNumber =orderNumber;
19. }
20. @Id
21. @GeneratedValue
22. @Column(name="ID")
23. private Long id;
24. @Column(name="ORDER_NUMBER",length=15)
25. private String orderNumber;
26. @ManyToOne(fetch = FetchType.EAGER,cascade=CascadeType.ALL)
27. @JoinColumn(name="CUSTOMER_ID")
28. private Customer customer;
29. public Long getId() {
30. return id;
31. }
32. public void setId(Long id) {
33. this.id = id;
34. }
35. public String getOrderNumber() {
36. return orderNumber;
37. }
38. public void setOrderNumber(String orderNumber) {
39. this.orderNumber = orderNumber;
40. }
41. public Customer getCustomer() {
42. return customer;
43. }
44. public void setCustomer(Customer customer) {
45. this.customer = customer;
46. }
47. }

[java] view
plaincopy

1. package com.lwp.hibernate.Model;
2. import java.io.Serializable;
3. import java.util.HashSet;
4. import java.util.Set;
5. import javax.persistence.Column;
6. import javax.persistence.Entity;
7. import javax.persistence.GeneratedValue;
8. import javax.persistence.Id;
9. import javax.persistence.OneToMany;
10. import javax.persistence.Table;
11. @Entity
12. @Table
13. public class Customer implements Serializable{
14. private static final long serialVersionUID = 1L;
15. public Customer(){}
16. public Customer(String name,Set<Order> orders){
17. this.name=name;
18. this.orders = orders;
19. }
20. @Id
21. @GeneratedValue
22. @Column(name="ID")
23. private Long id;
24. @Column(name="NAME",length=15)
25. private String name;
26. @OneToMany(mappedBy="customer")
27. private Set<Order> orders = new HashSet<Order>();
28. public Set<Order> getOrders() {
29. return orders;
30. }
31. public void setOrders(Set<Order> orders) {
32. this.orders = orders;
33. }
34. public Long getId() {
35. return id;
36. }
37. public void setId(Long id) {
38. this.id = id;
39. }
40. public String getName() {
41. return name;
42. }
43. public void setName(String name) {
44. this.name = name;
45. }
46. }

[java] view
plaincopy

1. import java.util.HashSet;
2. import java.util.Set;
3. import org.hibernate.Session;
4. import org.hibernate.SessionFactory;
5. import org.hibernate.cfg.AnnotationConfiguration;
6. import org.hibernate.cfg.Configuration;
7. import org.hibernate.tool.hbm2ddl.SchemaExport;
8. import com.lwp.hibernate.Model.Customer;
9. import com.lwp.hibernate.Model.Order;
10. public class CustomerTest {
11. public static void main(String[] args) {
12. new SchemaExport(new AnnotationConfiguration().configure("/hibernate.cfg.xml")).create(true, false);
13. Set<Order> orders =  new HashSet<Order>();
14. Order order1 = new Order("Tom_Order001");
15. Order order2 = new Order("Tom_Order002");
16. orders.add(order1);
17. orders.add(order2);
18. Customer customer = new Customer("Tom",orders);
19. order1.setCustomer(customer);
20. order2.setCustomer(customer);
21. //save(customer);
22. save(order1);
23. save(order2);
24. }
25. public static void save(Object o){
26. //Configuration cfg = new Configuration();//xx.hbm.xml形式下的new
27. Configuration cfg = new AnnotationConfiguration(); //Annotation形式下的new
28. SessionFactory sf = cfg.configure().buildSessionFactory();
29. Session session = sf.openSession();
30. session.beginTransaction();
31. session.save(o);
32. session.getTransaction().commit();
33. session.close();
34. sf.close();
35. }
36. }

注：这里不用save customer, save order时就会保存customer。因为mappedBy 相当于Inverse=value,既让Many一方来维护。